ILGenerator.Emit 方法

參考

定義

命名空間:: System.Reflection.Emit

組件:: System.Reflection.Emit.ILGeneration.dll

組件:: mscorlib.dll

組件:: netstandard.dll

重要

部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。

放置指令到 Just-In-Time (JIT) 編譯器的 Microsoft Intermediate Language (MSIL) 資料流中。

多載

Emit(OpCode, LocalBuilder)	放置指定的指令到 Microsoft Intermediate Language (MSIL) 資料流，然後放置指定區域變數的索引。
Emit(OpCode, Type)	放置指定的指令到 Microsoft Intermediate Language (MSIL) 資料流，然後放置指定型別的中繼資料語彙基元。
Emit(OpCode, String)	放置指定的指令到 Microsoft Intermediate Language (MSIL) 資料流，然後放置指定字串的中繼資料語彙基元。
Emit(OpCode, Single)	放置指定的指令和數值引數到指令的 Microsoft Intermediate Language (MSIL) 資料流。
Emit(OpCode, SByte)	放置指定的指令和字元引數到指令的 Microsoft Intermediate Language (MSIL) 資料流。
Emit(OpCode, MethodInfo)	放置指定的指令到 Microsoft Intermediate Language (MSIL) 資料流，然後放置指定方法的中繼資料語彙基元。
Emit(OpCode, SignatureHelper)	放置指定的指令和簽章語彙基元到指令的 Microsoft Intermediate Language (MSIL) 資料流。
Emit(OpCode, Label[])	放置指定的指令到 Microsoft Intermediate Language (MSIL) 資料流中，並留下空間，以便在完成修復時加入標記。
Emit(OpCode, FieldInfo)	放置指定欄位的指定指令和中繼資料語彙基元到指令的 Microsoft Intermediate Language (MSIL) 資料流中。
Emit(OpCode, ConstructorInfo)	放置指定建構函式的指定指令和中繼資料 (Metadata) 語彙基元到指令的 Microsoft Intermediate Language (MSIL) 資料流中。
Emit(OpCode, Int64)	放置指定的指令和數值引數到指令的 Microsoft Intermediate Language (MSIL) 資料流。
Emit(OpCode, Int32)	放置指定的指令和數值引數到指令的 Microsoft Intermediate Language (MSIL) 資料流。
Emit(OpCode, Int16)	放置指定的指令和數值引數到指令的 Microsoft Intermediate Language (MSIL) 資料流。
Emit(OpCode, Double)	放置指定的指令和數值引數到指令的 Microsoft Intermediate Language (MSIL) 資料流。
Emit(OpCode, Byte)	放置指定的指令和字元引數到指令的 Microsoft Intermediate Language (MSIL) 資料流。
Emit(OpCode)	放置指定的指令到指令資料流中。
Emit(OpCode, Label)	放置指定的指令到 Microsoft Intermediate Language (MSIL) 資料流中，並留下空間，以便在完成修復時加入標記。

Emit(OpCode, LocalBuilder)

Source:: ILGenerator.cs

Source:: ILGenerator.cs

Source:: ILGenerator.cs

放置指定的指令到 Microsoft Intermediate Language (MSIL) 資料流，然後放置指定區域變數的索引。

public:
 virtual void Emit(System::Reflection::Emit::OpCode opcode, System::Reflection::Emit::LocalBuilder ^ local);

public:
 abstract void Emit(System::Reflection::Emit::OpCode opcode, System::Reflection::Emit::LocalBuilder ^ local);

public virtual void Emit (System.Reflection.Emit.OpCode opcode, System.Reflection.Emit.LocalBuilder local);

public abstract void Emit (System.Reflection.Emit.OpCode opcode, System.Reflection.Emit.LocalBuilder local);

abstract member Emit : System.Reflection.Emit.OpCode * System.Reflection.Emit.LocalBuilder -> unit
override this.Emit : System.Reflection.Emit.OpCode * System.Reflection.Emit.LocalBuilder -> unit

abstract member Emit : System.Reflection.Emit.OpCode * System.Reflection.Emit.LocalBuilder -> unit

Public Overridable Sub Emit (opcode As OpCode, local As LocalBuilder)

Public MustOverride Sub Emit (opcode As OpCode, local As LocalBuilder)

參數

opcode: OpCode

要在資料流中發出的 MSIL 指令。

local: LocalBuilder

區域變數。

例外狀況

ArgumentException

local 參數的父方法與這個 ILGenerator 的相關聯方法不相符。

ArgumentNullException

local 為 null。

InvalidOperationException

opcode 是單一位元組的指令，而 local 表示索引大於 Byte.MaxValue 的區域變數。

備註

指令值定義于列舉中 OpCodes 。

適用於

Emit(OpCode, Type)

Source:: ILGenerator.cs

Source:: ILGenerator.cs

Source:: ILGenerator.cs

放置指定的指令到 Microsoft Intermediate Language (MSIL) 資料流，然後放置指定型別的中繼資料語彙基元。

public:
 virtual void Emit(System::Reflection::Emit::OpCode opcode, Type ^ cls);

public:
 abstract void Emit(System::Reflection::Emit::OpCode opcode, Type ^ cls);

public virtual void Emit (System.Reflection.Emit.OpCode opcode, Type cls);

public abstract void Emit (System.Reflection.Emit.OpCode opcode, Type cls);

abstract member Emit : System.Reflection.Emit.OpCode * Type -> unit
override this.Emit : System.Reflection.Emit.OpCode * Type -> unit

abstract member Emit : System.Reflection.Emit.OpCode * Type -> unit

Public Overridable Sub Emit (opcode As OpCode, cls As Type)

Public MustOverride Sub Emit (opcode As OpCode, cls As Type)

參數

opcode: OpCode

MSIL 指令，要放置到資料流中。

cls: Type

Type。

例外狀況

ArgumentNullException

cls 為 null。

備註

指令值定義于列舉中 OpCodes 。的位置 cls 會記錄，以便在將模組保存到可攜式可執行檔時，視需要修補權杖， (PE) 檔案。

適用於

Emit(OpCode, String)

Source:: ILGenerator.cs

Source:: ILGenerator.cs

Source:: ILGenerator.cs

放置指定的指令到 Microsoft Intermediate Language (MSIL) 資料流，然後放置指定字串的中繼資料語彙基元。

public:
 virtual void Emit(System::Reflection::Emit::OpCode opcode, System::String ^ str);

public:
 abstract void Emit(System::Reflection::Emit::OpCode opcode, System::String ^ str);

public virtual void Emit (System.Reflection.Emit.OpCode opcode, string str);

public abstract void Emit (System.Reflection.Emit.OpCode opcode, string str);

abstract member Emit : System.Reflection.Emit.OpCode * string -> unit
override this.Emit : System.Reflection.Emit.OpCode * string -> unit

abstract member Emit : System.Reflection.Emit.OpCode * string -> unit

Public Overridable Sub Emit (opcode As OpCode, str As String)

Public MustOverride Sub Emit (opcode As OpCode, str As String)

參數

opcode: OpCode

要在資料流中發出的 MSIL 指令。

str: String

要發出的 String。

備註

指令值定義于列舉中 OpCodes 。如果模組保存到可攜式可執行檔 (PE) 檔案，則會記錄位置 str 以供日後修正。

適用於

Emit(OpCode, Single)

Source:: ILGenerator.cs

Source:: ILGenerator.cs

Source:: ILGenerator.cs

放置指定的指令和數值引數到指令的 Microsoft Intermediate Language (MSIL) 資料流。

public:
 virtual void Emit(System::Reflection::Emit::OpCode opcode, float arg);

public:
 abstract void Emit(System::Reflection::Emit::OpCode opcode, float arg);

public virtual void Emit (System.Reflection.Emit.OpCode opcode, float arg);

public abstract void Emit (System.Reflection.Emit.OpCode opcode, float arg);

abstract member Emit : System.Reflection.Emit.OpCode * single -> unit
override this.Emit : System.Reflection.Emit.OpCode * single -> unit

abstract member Emit : System.Reflection.Emit.OpCode * single -> unit

Public Overridable Sub Emit (opcode As OpCode, arg As Single)

Public MustOverride Sub Emit (opcode As OpCode, arg As Single)

參數

opcode: OpCode

MSIL 指令，要放置到資料流中。

arg: Single

Single 引數，緊接指令之後立即被推入資料流。

備註

指令值定義于列舉中 OpCodes 。

適用於

Emit(OpCode, SByte)

Source:: ILGenerator.cs

Source:: ILGenerator.cs

Source:: ILGenerator.cs

重要

此 API 不符合 CLS 規範。

放置指定的指令和字元引數到指令的 Microsoft Intermediate Language (MSIL) 資料流。

public:
 void Emit(System::Reflection::Emit::OpCode opcode, System::SByte arg);

[System.CLSCompliant(false)]
public void Emit (System.Reflection.Emit.OpCode opcode, sbyte arg);

[<System.CLSCompliant(false)>]
member this.Emit : System.Reflection.Emit.OpCode * sbyte -> unit

Public Sub Emit (opcode As OpCode, arg As SByte)

參數

opcode: OpCode

MSIL 指令，要放置到資料流中。

arg: SByte

字元引數，緊接指令之後立即被推入資料流。

屬性: CLSCompliantAttribute

備註

指令值定義于列舉中 OpCodes 。

適用於

Emit(OpCode, MethodInfo)

Source:: ILGenerator.cs

Source:: ILGenerator.cs

Source:: ILGenerator.cs

放置指定的指令到 Microsoft Intermediate Language (MSIL) 資料流，然後放置指定方法的中繼資料語彙基元。

public:
 virtual void Emit(System::Reflection::Emit::OpCode opcode, System::Reflection::MethodInfo ^ meth);

public:
 abstract void Emit(System::Reflection::Emit::OpCode opcode, System::Reflection::MethodInfo ^ meth);

public virtual void Emit (System.Reflection.Emit.OpCode opcode, System.Reflection.MethodInfo meth);

public abstract void Emit (System.Reflection.Emit.OpCode opcode, System.Reflection.MethodInfo meth);

abstract member Emit : System.Reflection.Emit.OpCode * System.Reflection.MethodInfo -> unit
override this.Emit : System.Reflection.Emit.OpCode * System.Reflection.MethodInfo -> unit

abstract member Emit : System.Reflection.Emit.OpCode * System.Reflection.MethodInfo -> unit

Public Overridable Sub Emit (opcode As OpCode, meth As MethodInfo)

Public MustOverride Sub Emit (opcode As OpCode, meth As MethodInfo)

參數

opcode: OpCode

要在資料流中發出的 MSIL 指令。

meth: MethodInfo

MethodInfo，表示方法。

例外狀況

ArgumentNullException

meth 為 null。

NotSupportedException

meth 是泛型方法，其 IsGenericMethodDefinition 屬性為 false。

備註

指令值定義于列舉中 OpCodes 。

的位置 meth 會記錄，以便在將模組保存到可攜式可執行檔 (PE) 檔案時，視需要修補指令資料流程。

如果 meth 表示泛型方法，它必須是泛型方法定義。也就是說，其 MethodInfo.IsGenericMethodDefinition 屬性必須是 true 。

適用於

Emit(OpCode, SignatureHelper)

Source:: ILGenerator.cs

Source:: ILGenerator.cs

Source:: ILGenerator.cs

放置指定的指令和簽章語彙基元到指令的 Microsoft Intermediate Language (MSIL) 資料流。

public:
 virtual void Emit(System::Reflection::Emit::OpCode opcode, System::Reflection::Emit::SignatureHelper ^ signature);

public:
 abstract void Emit(System::Reflection::Emit::OpCode opcode, System::Reflection::Emit::SignatureHelper ^ signature);

public virtual void Emit (System.Reflection.Emit.OpCode opcode, System.Reflection.Emit.SignatureHelper signature);

public abstract void Emit (System.Reflection.Emit.OpCode opcode, System.Reflection.Emit.SignatureHelper signature);

abstract member Emit : System.Reflection.Emit.OpCode * System.Reflection.Emit.SignatureHelper -> unit
override this.Emit : System.Reflection.Emit.OpCode * System.Reflection.Emit.SignatureHelper -> unit

abstract member Emit : System.Reflection.Emit.OpCode * System.Reflection.Emit.SignatureHelper -> unit

Public Overridable Sub Emit (opcode As OpCode, signature As SignatureHelper)

Public MustOverride Sub Emit (opcode As OpCode, signature As SignatureHelper)

參數

opcode: OpCode

要在資料流中發出的 MSIL 指令。

signature: SignatureHelper

Helper，用來建構簽章語彙基元。

例外狀況

ArgumentNullException

signature 為 null。

備註

指令值定義于列舉中 OpCodes 。

適用於

Emit(OpCode, Label[])

Source:: ILGenerator.cs

Source:: ILGenerator.cs

Source:: ILGenerator.cs

放置指定的指令到 Microsoft Intermediate Language (MSIL) 資料流中，並留下空間，以便在完成修復時加入標記。

public:
 virtual void Emit(System::Reflection::Emit::OpCode opcode, cli::array <System::Reflection::Emit::Label> ^ labels);

public:
 abstract void Emit(System::Reflection::Emit::OpCode opcode, cli::array <System::Reflection::Emit::Label> ^ labels);

public virtual void Emit (System.Reflection.Emit.OpCode opcode, System.Reflection.Emit.Label[] labels);

public abstract void Emit (System.Reflection.Emit.OpCode opcode, System.Reflection.Emit.Label[] labels);

abstract member Emit : System.Reflection.Emit.OpCode * System.Reflection.Emit.Label[] -> unit
override this.Emit : System.Reflection.Emit.OpCode * System.Reflection.Emit.Label[] -> unit

abstract member Emit : System.Reflection.Emit.OpCode * System.Reflection.Emit.Label[] -> unit

Public Overridable Sub Emit (opcode As OpCode, labels As Label())

Public MustOverride Sub Emit (opcode As OpCode, labels As Label())

參數

opcode: OpCode

要在資料流中發出的 MSIL 指令。

labels: Label[]

標記物件陣列，要從這個位置分支至的。會用到所有的標記。

例外狀況

ArgumentNullException

con 為 null。此例外狀況是 .NET Framework 4 中的新功能。

範例

下列程式碼範例說明如何建立具有跳躍資料表的動態方法。跳躍資料表是使用的 Label 陣列所建置。

using namespace System;
using namespace System::Threading;
using namespace System::Reflection;
using namespace System::Reflection::Emit;
Type^ BuildMyType()
{
   AppDomain^ myDomain = Thread::GetDomain();
   AssemblyName^ myAsmName = gcnew AssemblyName;
   myAsmName->Name = "MyDynamicAssembly";
   AssemblyBuilder^ myAsmBuilder = myDomain->DefineDynamicAssembly( myAsmName, AssemblyBuilderAccess::Run );
   ModuleBuilder^ myModBuilder = myAsmBuilder->DefineDynamicModule( "MyJumpTableDemo" );
   TypeBuilder^ myTypeBuilder = myModBuilder->DefineType( "JumpTableDemo", TypeAttributes::Public );
   array<Type^>^temp0 = {int::typeid};
   MethodBuilder^ myMthdBuilder = myTypeBuilder->DefineMethod( "SwitchMe", static_cast<MethodAttributes>(MethodAttributes::Public | MethodAttributes::Static), String::typeid, temp0 );
   ILGenerator^ myIL = myMthdBuilder->GetILGenerator();
   Label defaultCase = myIL->DefineLabel();
   Label endOfMethod = myIL->DefineLabel();
   
   // We are initializing our jump table. Note that the labels
   // will be placed later using the MarkLabel method.
   array<Label>^jumpTable = gcnew array<Label>(5);
   jumpTable[ 0 ] = myIL->DefineLabel();
   jumpTable[ 1 ] = myIL->DefineLabel();
   jumpTable[ 2 ] = myIL->DefineLabel();
   jumpTable[ 3 ] = myIL->DefineLabel();
   jumpTable[ 4 ] = myIL->DefineLabel();
   
   // arg0, the number we passed, is pushed onto the stack.
   // In this case, due to the design of the code sample,
   // the value pushed onto the stack happens to match the
   // index of the label (in IL terms, the index of the offset
   // in the jump table). If this is not the case, such as
   // when switching based on non-integer values, rules for the correspondence
   // between the possible case values and each index of the offsets
   // must be established outside of the ILGenerator::Emit calls,
   // much as a compiler would.
   myIL->Emit( OpCodes::Ldarg_0 );
   myIL->Emit( OpCodes::Switch, jumpTable );
   
   // Branch on default case
   myIL->Emit( OpCodes::Br_S, defaultCase );
   
   // Case arg0 = 0
   myIL->MarkLabel( jumpTable[ 0 ] );
   myIL->Emit( OpCodes::Ldstr, "are no bananas" );
   myIL->Emit( OpCodes::Br_S, endOfMethod );
   
   // Case arg0 = 1
   myIL->MarkLabel( jumpTable[ 1 ] );
   myIL->Emit( OpCodes::Ldstr, "is one banana" );
   myIL->Emit( OpCodes::Br_S, endOfMethod );
   
   // Case arg0 = 2
   myIL->MarkLabel( jumpTable[ 2 ] );
   myIL->Emit( OpCodes::Ldstr, "are two bananas" );
   myIL->Emit( OpCodes::Br_S, endOfMethod );
   
   // Case arg0 = 3
   myIL->MarkLabel( jumpTable[ 3 ] );
   myIL->Emit( OpCodes::Ldstr, "are three bananas" );
   myIL->Emit( OpCodes::Br_S, endOfMethod );
   
   // Case arg0 = 4
   myIL->MarkLabel( jumpTable[ 4 ] );
   myIL->Emit( OpCodes::Ldstr, "are four bananas" );
   myIL->Emit( OpCodes::Br_S, endOfMethod );
   
   // Default case
   myIL->MarkLabel( defaultCase );
   myIL->Emit( OpCodes::Ldstr, "are many bananas" );
   myIL->MarkLabel( endOfMethod );
   myIL->Emit( OpCodes::Ret );
   return myTypeBuilder->CreateType();
}

int main()
{
   Type^ myType = BuildMyType();
   Console::Write( "Enter an integer between 0 and 5: " );
   int theValue = Convert::ToInt32( Console::ReadLine() );
   Console::WriteLine( "---" );
   Object^ myInstance = Activator::CreateInstance( myType, gcnew array<Object^>(0) );
   array<Object^>^temp1 = {theValue};
   Console::WriteLine( "Yes, there {0} today!", myType->InvokeMember( "SwitchMe", BindingFlags::InvokeMethod, nullptr, myInstance, temp1 ) );
}

using System;
using System.Threading;
using System.Reflection;
using System.Reflection.Emit;

class DynamicJumpTableDemo
{
   public static Type BuildMyType()
   {
    AppDomain myDomain = Thread.GetDomain();
    AssemblyName myAsmName = new AssemblyName();
    myAsmName.Name = "MyDynamicAssembly";

    AssemblyBuilder myAsmBuilder = myDomain.DefineDynamicAssembly(
                        myAsmName,
                        AssemblyBuilderAccess.Run);
    ModuleBuilder myModBuilder = myAsmBuilder.DefineDynamicModule(
                        "MyJumpTableDemo");

    TypeBuilder myTypeBuilder = myModBuilder.DefineType("JumpTableDemo",
                            TypeAttributes.Public);
    MethodBuilder myMthdBuilder = myTypeBuilder.DefineMethod("SwitchMe",
                             MethodAttributes.Public |
                             MethodAttributes.Static,
                                             typeof(string),
                                             new Type[] {typeof(int)});

    ILGenerator myIL = myMthdBuilder.GetILGenerator();

    Label defaultCase = myIL.DefineLabel();	
    Label endOfMethod = myIL.DefineLabel();	

    // We are initializing our jump table. Note that the labels
    // will be placed later using the MarkLabel method.

    Label[] jumpTable = new Label[] { myIL.DefineLabel(),
                      myIL.DefineLabel(),
                      myIL.DefineLabel(),
                      myIL.DefineLabel(),
                      myIL.DefineLabel() };

    // arg0, the number we passed, is pushed onto the stack.
    // In this case, due to the design of the code sample,
    // the value pushed onto the stack happens to match the
    // index of the label (in IL terms, the index of the offset
    // in the jump table). If this is not the case, such as
    // when switching based on non-integer values, rules for the correspondence
    // between the possible case values and each index of the offsets
    // must be established outside of the ILGenerator.Emit calls,
    // much as a compiler would.

    myIL.Emit(OpCodes.Ldarg_0);
    myIL.Emit(OpCodes.Switch, jumpTable);
    
    // Branch on default case
    myIL.Emit(OpCodes.Br_S, defaultCase);

    // Case arg0 = 0
    myIL.MarkLabel(jumpTable[0]);
    myIL.Emit(OpCodes.Ldstr, "are no bananas");
    myIL.Emit(OpCodes.Br_S, endOfMethod);

    // Case arg0 = 1
    myIL.MarkLabel(jumpTable[1]);
    myIL.Emit(OpCodes.Ldstr, "is one banana");
    myIL.Emit(OpCodes.Br_S, endOfMethod);

    // Case arg0 = 2
    myIL.MarkLabel(jumpTable[2]);
    myIL.Emit(OpCodes.Ldstr, "are two bananas");
    myIL.Emit(OpCodes.Br_S, endOfMethod);

    // Case arg0 = 3
    myIL.MarkLabel(jumpTable[3]);
    myIL.Emit(OpCodes.Ldstr, "are three bananas");
    myIL.Emit(OpCodes.Br_S, endOfMethod);

    // Case arg0 = 4
    myIL.MarkLabel(jumpTable[4]);
    myIL.Emit(OpCodes.Ldstr, "are four bananas");
    myIL.Emit(OpCodes.Br_S, endOfMethod);

    // Default case
    myIL.MarkLabel(defaultCase);
    myIL.Emit(OpCodes.Ldstr, "are many bananas");

    myIL.MarkLabel(endOfMethod);
    myIL.Emit(OpCodes.Ret);
    
    return myTypeBuilder.CreateType();
   }

   public static void Main()
   {
    Type myType = BuildMyType();
    
    Console.Write("Enter an integer between 0 and 5: ");
    int theValue = Convert.ToInt32(Console.ReadLine());

    Console.WriteLine("---");
    Object myInstance = Activator.CreateInstance(myType, new object[0]);	
    Console.WriteLine("Yes, there {0} today!", myType.InvokeMember("SwitchMe",
                               BindingFlags.InvokeMethod,
                               null,
                               myInstance,
                               new object[] {theValue}));
   }
}


Imports System.Threading
Imports System.Reflection
Imports System.Reflection.Emit

 _

Class DynamicJumpTableDemo
   
   Public Shared Function BuildMyType() As Type

      Dim myDomain As AppDomain = Thread.GetDomain()
      Dim myAsmName As New AssemblyName()
      myAsmName.Name = "MyDynamicAssembly"
      
      Dim myAsmBuilder As AssemblyBuilder = myDomain.DefineDynamicAssembly(myAsmName, _
                            AssemblyBuilderAccess.Run)
      Dim myModBuilder As ModuleBuilder = myAsmBuilder.DefineDynamicModule("MyJumpTableDemo")
      
      Dim myTypeBuilder As TypeBuilder = myModBuilder.DefineType("JumpTableDemo", _
                                 TypeAttributes.Public)
      Dim myMthdBuilder As MethodBuilder = myTypeBuilder.DefineMethod("SwitchMe", _
                        MethodAttributes.Public Or MethodAttributes.Static, _
                        GetType(String), New Type() {GetType(Integer)})
      
      Dim myIL As ILGenerator = myMthdBuilder.GetILGenerator()
      
      Dim defaultCase As Label = myIL.DefineLabel()
      Dim endOfMethod As Label = myIL.DefineLabel()
      
      ' We are initializing our jump table. Note that the labels
      ' will be placed later using the MarkLabel method. 

      Dim jumpTable() As Label = {myIL.DefineLabel(), _
                  myIL.DefineLabel(), _
                  myIL.DefineLabel(), _
                  myIL.DefineLabel(), _
                  myIL.DefineLabel()}
      
      ' arg0, the number we passed, is pushed onto the stack.
      ' In this case, due to the design of the code sample,
      ' the value pushed onto the stack happens to match the
      ' index of the label (in IL terms, the index of the offset
      ' in the jump table). If this is not the case, such as
      ' when switching based on non-integer values, rules for the correspondence
      ' between the possible case values and each index of the offsets
      ' must be established outside of the ILGenerator.Emit calls,
      ' much as a compiler would.

      myIL.Emit(OpCodes.Ldarg_0)
      myIL.Emit(OpCodes.Switch, jumpTable)
      
      ' Branch on default case
      myIL.Emit(OpCodes.Br_S, defaultCase)
      
      ' Case arg0 = 0
      myIL.MarkLabel(jumpTable(0))
      myIL.Emit(OpCodes.Ldstr, "are no bananas")
      myIL.Emit(OpCodes.Br_S, endOfMethod)
      
      ' Case arg0 = 1
      myIL.MarkLabel(jumpTable(1))
      myIL.Emit(OpCodes.Ldstr, "is one banana")
      myIL.Emit(OpCodes.Br_S, endOfMethod)
      
      ' Case arg0 = 2
      myIL.MarkLabel(jumpTable(2))
      myIL.Emit(OpCodes.Ldstr, "are two bananas")
      myIL.Emit(OpCodes.Br_S, endOfMethod)
      
      ' Case arg0 = 3
      myIL.MarkLabel(jumpTable(3))
      myIL.Emit(OpCodes.Ldstr, "are three bananas")
      myIL.Emit(OpCodes.Br_S, endOfMethod)
      
      ' Case arg0 = 4
      myIL.MarkLabel(jumpTable(4))
      myIL.Emit(OpCodes.Ldstr, "are four bananas")
      myIL.Emit(OpCodes.Br_S, endOfMethod)
      
      ' Default case
      myIL.MarkLabel(defaultCase)
      myIL.Emit(OpCodes.Ldstr, "are many bananas")
      
      myIL.MarkLabel(endOfMethod)
      myIL.Emit(OpCodes.Ret)
      
      Return myTypeBuilder.CreateType()

   End Function 'BuildMyType
    
   
   Public Shared Sub Main()

      Dim myType As Type = BuildMyType()
      
      Console.Write("Enter an integer between 0 and 5: ")
      Dim theValue As Integer = Convert.ToInt32(Console.ReadLine())
      
      Console.WriteLine("---")
      Dim myInstance As [Object] = Activator.CreateInstance(myType, New Object() {})
      Console.WriteLine("Yes, there {0} today!", myType.InvokeMember("SwitchMe", _
                         BindingFlags.InvokeMethod, Nothing, _
                             myInstance, New Object() {theValue}))

   End Sub

End Class

備註

發出參數資料表。

指令值定義于列舉中 OpCodes 。

標籤是使用來 DefineLabel 建立的，而且其位於資料流程內的位置是使用 MarkLabel 來修正。如果使用單一位元組指令，標籤可以代表資料流程最多 127 個位元組的跳躍。 opcode 必須代表分支指令。因為分支是相對指示， label 所以會在修正程式期間，以分支的正確位移取代。

適用於

Emit(OpCode, FieldInfo)

Source:: ILGenerator.cs

Source:: ILGenerator.cs

Source:: ILGenerator.cs

放置指定欄位的指定指令和中繼資料語彙基元到指令的 Microsoft Intermediate Language (MSIL) 資料流中。

public:
 virtual void Emit(System::Reflection::Emit::OpCode opcode, System::Reflection::FieldInfo ^ field);

public:
 abstract void Emit(System::Reflection::Emit::OpCode opcode, System::Reflection::FieldInfo ^ field);

public virtual void Emit (System.Reflection.Emit.OpCode opcode, System.Reflection.FieldInfo field);

public abstract void Emit (System.Reflection.Emit.OpCode opcode, System.Reflection.FieldInfo field);

abstract member Emit : System.Reflection.Emit.OpCode * System.Reflection.FieldInfo -> unit
override this.Emit : System.Reflection.Emit.OpCode * System.Reflection.FieldInfo -> unit

abstract member Emit : System.Reflection.Emit.OpCode * System.Reflection.FieldInfo -> unit

Public Overridable Sub Emit (opcode As OpCode, field As FieldInfo)

Public MustOverride Sub Emit (opcode As OpCode, field As FieldInfo)

參數

opcode: OpCode

要在資料流中發出的 MSIL 指令。

field: FieldInfo

FieldInfo，表示欄位。

備註

指令值定義于列舉中 OpCodes 。的位置 field 會記錄，以便在將模組保存到可攜式可執行檔 (PE) 檔案時，視需要修補指令資料流程。

適用於

Emit(OpCode, ConstructorInfo)

Source:: ILGenerator.cs

Source:: ILGenerator.cs

Source:: ILGenerator.cs

放置指定建構函式的指定指令和中繼資料 (Metadata) 語彙基元到指令的 Microsoft Intermediate Language (MSIL) 資料流中。

public:
 virtual void Emit(System::Reflection::Emit::OpCode opcode, System::Reflection::ConstructorInfo ^ con);

public:
 abstract void Emit(System::Reflection::Emit::OpCode opcode, System::Reflection::ConstructorInfo ^ con);

public virtual void Emit (System.Reflection.Emit.OpCode opcode, System.Reflection.ConstructorInfo con);

public abstract void Emit (System.Reflection.Emit.OpCode opcode, System.Reflection.ConstructorInfo con);

[System.Runtime.InteropServices.ComVisible(true)]
public virtual void Emit (System.Reflection.Emit.OpCode opcode, System.Reflection.ConstructorInfo con);

abstract member Emit : System.Reflection.Emit.OpCode * System.Reflection.ConstructorInfo -> unit
override this.Emit : System.Reflection.Emit.OpCode * System.Reflection.ConstructorInfo -> unit

abstract member Emit : System.Reflection.Emit.OpCode * System.Reflection.ConstructorInfo -> unit

[<System.Runtime.InteropServices.ComVisible(true)>]
abstract member Emit : System.Reflection.Emit.OpCode * System.Reflection.ConstructorInfo -> unit
override this.Emit : System.Reflection.Emit.OpCode * System.Reflection.ConstructorInfo -> unit

Public Overridable Sub Emit (opcode As OpCode, con As ConstructorInfo)

Public MustOverride Sub Emit (opcode As OpCode, con As ConstructorInfo)

參數

opcode: OpCode

要在資料流中發出的 MSIL 指令。

con: ConstructorInfo

ConstructorInfo，表示建構函式。

屬性: ComVisibleAttribute

例外狀況

ArgumentNullException

con 為 null。此例外狀況是.NET Framework 4 中的新功能。

備註

指令值定義于列舉中 OpCodes 。

的位置 con 會記錄，以便在將模組保存到可攜式可執行檔時，視需要修補指令資料流程， (PE) 檔案。

適用於

Emit(OpCode, Int64)

Source:: ILGenerator.cs

Source:: ILGenerator.cs

Source:: ILGenerator.cs

放置指定的指令和數值引數到指令的 Microsoft Intermediate Language (MSIL) 資料流。

public:
 virtual void Emit(System::Reflection::Emit::OpCode opcode, long arg);

public:
 abstract void Emit(System::Reflection::Emit::OpCode opcode, long arg);

public virtual void Emit (System.Reflection.Emit.OpCode opcode, long arg);

public abstract void Emit (System.Reflection.Emit.OpCode opcode, long arg);

abstract member Emit : System.Reflection.Emit.OpCode * int64 -> unit
override this.Emit : System.Reflection.Emit.OpCode * int64 -> unit

abstract member Emit : System.Reflection.Emit.OpCode * int64 -> unit

Public Overridable Sub Emit (opcode As OpCode, arg As Long)

Public MustOverride Sub Emit (opcode As OpCode, arg As Long)

參數

opcode: OpCode

MSIL 指令，要放置到資料流中。

arg: Int64

數字引數，緊接指令之後立即被推入資料流。

備註

指令值定義于列舉中 OpCodes 。

適用於

Emit(OpCode, Int32)

Source:: ILGenerator.cs

Source:: ILGenerator.cs

Source:: ILGenerator.cs

放置指定的指令和數值引數到指令的 Microsoft Intermediate Language (MSIL) 資料流。

public:
 virtual void Emit(System::Reflection::Emit::OpCode opcode, int arg);

public:
 abstract void Emit(System::Reflection::Emit::OpCode opcode, int arg);

public virtual void Emit (System.Reflection.Emit.OpCode opcode, int arg);

public abstract void Emit (System.Reflection.Emit.OpCode opcode, int arg);

abstract member Emit : System.Reflection.Emit.OpCode * int -> unit
override this.Emit : System.Reflection.Emit.OpCode * int -> unit

abstract member Emit : System.Reflection.Emit.OpCode * int -> unit

Public Overridable Sub Emit (opcode As OpCode, arg As Integer)

Public MustOverride Sub Emit (opcode As OpCode, arg As Integer)

參數

opcode: OpCode

MSIL 指令，要放置到資料流中。

arg: Int32

數字引數，緊接指令之後立即被推入資料流。

備註

指令值定義于列舉中 OpCodes 。

適用於

Emit(OpCode, Int16)

Source:: ILGenerator.cs

Source:: ILGenerator.cs

Source:: ILGenerator.cs

放置指定的指令和數值引數到指令的 Microsoft Intermediate Language (MSIL) 資料流。

public:
 virtual void Emit(System::Reflection::Emit::OpCode opcode, short arg);

public:
 abstract void Emit(System::Reflection::Emit::OpCode opcode, short arg);

public virtual void Emit (System.Reflection.Emit.OpCode opcode, short arg);

public abstract void Emit (System.Reflection.Emit.OpCode opcode, short arg);

abstract member Emit : System.Reflection.Emit.OpCode * int16 -> unit
override this.Emit : System.Reflection.Emit.OpCode * int16 -> unit

abstract member Emit : System.Reflection.Emit.OpCode * int16 -> unit

Public Overridable Sub Emit (opcode As OpCode, arg As Short)

Public MustOverride Sub Emit (opcode As OpCode, arg As Short)

參數

opcode: OpCode

要在資料流中發出的 MSIL 指令。

arg: Int16

Int 引數，緊接指令之後立即被推入資料流。

備註

指令值定義于列舉中 OpCodes 。

適用於

Emit(OpCode, Double)

Source:: ILGenerator.cs

Source:: ILGenerator.cs

Source:: ILGenerator.cs

放置指定的指令和數值引數到指令的 Microsoft Intermediate Language (MSIL) 資料流。

public:
 virtual void Emit(System::Reflection::Emit::OpCode opcode, double arg);

public:
 abstract void Emit(System::Reflection::Emit::OpCode opcode, double arg);

public virtual void Emit (System.Reflection.Emit.OpCode opcode, double arg);

public abstract void Emit (System.Reflection.Emit.OpCode opcode, double arg);

abstract member Emit : System.Reflection.Emit.OpCode * double -> unit
override this.Emit : System.Reflection.Emit.OpCode * double -> unit

abstract member Emit : System.Reflection.Emit.OpCode * double -> unit

Public Overridable Sub Emit (opcode As OpCode, arg As Double)

Public MustOverride Sub Emit (opcode As OpCode, arg As Double)

參數

opcode: OpCode

MSIL 指令，要放置到資料流中。已定義於 OpCodes 列舉型別中。

arg: Double

數字引數，緊接指令之後立即被推入資料流。

備註

指令值定義于列舉中 OpCodes 。

適用於

Emit(OpCode, Byte)

Source:: ILGenerator.cs

Source:: ILGenerator.cs

Source:: ILGenerator.cs

放置指定的指令和字元引數到指令的 Microsoft Intermediate Language (MSIL) 資料流。

public:
 virtual void Emit(System::Reflection::Emit::OpCode opcode, System::Byte arg);

public:
 abstract void Emit(System::Reflection::Emit::OpCode opcode, System::Byte arg);

public virtual void Emit (System.Reflection.Emit.OpCode opcode, byte arg);

public abstract void Emit (System.Reflection.Emit.OpCode opcode, byte arg);

abstract member Emit : System.Reflection.Emit.OpCode * byte -> unit
override this.Emit : System.Reflection.Emit.OpCode * byte -> unit

abstract member Emit : System.Reflection.Emit.OpCode * byte -> unit

Public Overridable Sub Emit (opcode As OpCode, arg As Byte)

Public MustOverride Sub Emit (opcode As OpCode, arg As Byte)

參數

opcode: OpCode

MSIL 指令，要放置到資料流中。

arg: Byte

字元引數，緊接指令之後立即被推入資料流。

備註

指令值定義于列舉中 OpCodes 。

適用於

Emit(OpCode)

Source:: ILGenerator.cs

Source:: ILGenerator.cs

Source:: ILGenerator.cs

放置指定的指令到指令資料流中。

public:
 virtual void Emit(System::Reflection::Emit::OpCode opcode);

public:
 abstract void Emit(System::Reflection::Emit::OpCode opcode);

public virtual void Emit (System.Reflection.Emit.OpCode opcode);

public abstract void Emit (System.Reflection.Emit.OpCode opcode);

abstract member Emit : System.Reflection.Emit.OpCode -> unit
override this.Emit : System.Reflection.Emit.OpCode -> unit

abstract member Emit : System.Reflection.Emit.OpCode -> unit

Public Overridable Sub Emit (opcode As OpCode)

Public MustOverride Sub Emit (opcode As OpCode)

參數

opcode: OpCode

Microsoft Intermediate Language (MSIL) 指令，要放置到資料流中。

範例

下列程式碼範例示範如何使用 Emit 透過的 ILGenerator 實例產生 MSIL 輸出。

using namespace System;
using namespace System::Threading;
using namespace System::Reflection;
using namespace System::Reflection::Emit;
Type^ BuildMyType()
{
   AppDomain^ myDomain = Thread::GetDomain();
   AssemblyName^ myAsmName = gcnew AssemblyName;
   myAsmName->Name = "MyDynamicAssembly";
   AssemblyBuilder^ myAsmBuilder = myDomain->DefineDynamicAssembly( myAsmName, AssemblyBuilderAccess::Run );
   ModuleBuilder^ myModBuilder = myAsmBuilder->DefineDynamicModule( "MyJumpTableDemo" );
   TypeBuilder^ myTypeBuilder = myModBuilder->DefineType( "JumpTableDemo", TypeAttributes::Public );
   array<Type^>^temp0 = {int::typeid};
   MethodBuilder^ myMthdBuilder = myTypeBuilder->DefineMethod( "SwitchMe", static_cast<MethodAttributes>(MethodAttributes::Public | MethodAttributes::Static), String::typeid, temp0 );
   ILGenerator^ myIL = myMthdBuilder->GetILGenerator();
   Label defaultCase = myIL->DefineLabel();
   Label endOfMethod = myIL->DefineLabel();
   
   // We are initializing our jump table. Note that the labels
   // will be placed later using the MarkLabel method.
   array<Label>^jumpTable = gcnew array<Label>(5);
   jumpTable[ 0 ] = myIL->DefineLabel();
   jumpTable[ 1 ] = myIL->DefineLabel();
   jumpTable[ 2 ] = myIL->DefineLabel();
   jumpTable[ 3 ] = myIL->DefineLabel();
   jumpTable[ 4 ] = myIL->DefineLabel();
   
   // arg0, the number we passed, is pushed onto the stack.
   // In this case, due to the design of the code sample,
   // the value pushed onto the stack happens to match the
   // index of the label (in IL terms, the index of the offset
   // in the jump table). If this is not the case, such as
   // when switching based on non-integer values, rules for the correspondence
   // between the possible case values and each index of the offsets
   // must be established outside of the ILGenerator::Emit calls,
   // much as a compiler would.
   myIL->Emit( OpCodes::Ldarg_0 );
   myIL->Emit( OpCodes::Switch, jumpTable );
   
   // Branch on default case
   myIL->Emit( OpCodes::Br_S, defaultCase );
   
   // Case arg0 = 0
   myIL->MarkLabel( jumpTable[ 0 ] );
   myIL->Emit( OpCodes::Ldstr, "are no bananas" );
   myIL->Emit( OpCodes::Br_S, endOfMethod );
   
   // Case arg0 = 1
   myIL->MarkLabel( jumpTable[ 1 ] );
   myIL->Emit( OpCodes::Ldstr, "is one banana" );
   myIL->Emit( OpCodes::Br_S, endOfMethod );
   
   // Case arg0 = 2
   myIL->MarkLabel( jumpTable[ 2 ] );
   myIL->Emit( OpCodes::Ldstr, "are two bananas" );
   myIL->Emit( OpCodes::Br_S, endOfMethod );
   
   // Case arg0 = 3
   myIL->MarkLabel( jumpTable[ 3 ] );
   myIL->Emit( OpCodes::Ldstr, "are three bananas" );
   myIL->Emit( OpCodes::Br_S, endOfMethod );
   
   // Case arg0 = 4
   myIL->MarkLabel( jumpTable[ 4 ] );
   myIL->Emit( OpCodes::Ldstr, "are four bananas" );
   myIL->Emit( OpCodes::Br_S, endOfMethod );
   
   // Default case
   myIL->MarkLabel( defaultCase );
   myIL->Emit( OpCodes::Ldstr, "are many bananas" );
   myIL->MarkLabel( endOfMethod );
   myIL->Emit( OpCodes::Ret );
   return myTypeBuilder->CreateType();
}

int main()
{
   Type^ myType = BuildMyType();
   Console::Write( "Enter an integer between 0 and 5: " );
   int theValue = Convert::ToInt32( Console::ReadLine() );
   Console::WriteLine( "---" );
   Object^ myInstance = Activator::CreateInstance( myType, gcnew array<Object^>(0) );
   array<Object^>^temp1 = {theValue};
   Console::WriteLine( "Yes, there {0} today!", myType->InvokeMember( "SwitchMe", BindingFlags::InvokeMethod, nullptr, myInstance, temp1 ) );
}

using System;
using System.Threading;
using System.Reflection;
using System.Reflection.Emit;

class DynamicJumpTableDemo
{
   public static Type BuildMyType()
   {
    AppDomain myDomain = Thread.GetDomain();
    AssemblyName myAsmName = new AssemblyName();
    myAsmName.Name = "MyDynamicAssembly";

    AssemblyBuilder myAsmBuilder = myDomain.DefineDynamicAssembly(
                        myAsmName,
                        AssemblyBuilderAccess.Run);
    ModuleBuilder myModBuilder = myAsmBuilder.DefineDynamicModule(
                        "MyJumpTableDemo");

    TypeBuilder myTypeBuilder = myModBuilder.DefineType("JumpTableDemo",
                            TypeAttributes.Public);
    MethodBuilder myMthdBuilder = myTypeBuilder.DefineMethod("SwitchMe",
                             MethodAttributes.Public |
                             MethodAttributes.Static,
                                             typeof(string),
                                             new Type[] {typeof(int)});

    ILGenerator myIL = myMthdBuilder.GetILGenerator();

    Label defaultCase = myIL.DefineLabel();	
    Label endOfMethod = myIL.DefineLabel();	

    // We are initializing our jump table. Note that the labels
    // will be placed later using the MarkLabel method.

    Label[] jumpTable = new Label[] { myIL.DefineLabel(),
                      myIL.DefineLabel(),
                      myIL.DefineLabel(),
                      myIL.DefineLabel(),
                      myIL.DefineLabel() };

    // arg0, the number we passed, is pushed onto the stack.
    // In this case, due to the design of the code sample,
    // the value pushed onto the stack happens to match the
    // index of the label (in IL terms, the index of the offset
    // in the jump table). If this is not the case, such as
    // when switching based on non-integer values, rules for the correspondence
    // between the possible case values and each index of the offsets
    // must be established outside of the ILGenerator.Emit calls,
    // much as a compiler would.

    myIL.Emit(OpCodes.Ldarg_0);
    myIL.Emit(OpCodes.Switch, jumpTable);
    
    // Branch on default case
    myIL.Emit(OpCodes.Br_S, defaultCase);

    // Case arg0 = 0
    myIL.MarkLabel(jumpTable[0]);
    myIL.Emit(OpCodes.Ldstr, "are no bananas");
    myIL.Emit(OpCodes.Br_S, endOfMethod);

    // Case arg0 = 1
    myIL.MarkLabel(jumpTable[1]);
    myIL.Emit(OpCodes.Ldstr, "is one banana");
    myIL.Emit(OpCodes.Br_S, endOfMethod);

    // Case arg0 = 2
    myIL.MarkLabel(jumpTable[2]);
    myIL.Emit(OpCodes.Ldstr, "are two bananas");
    myIL.Emit(OpCodes.Br_S, endOfMethod);

    // Case arg0 = 3
    myIL.MarkLabel(jumpTable[3]);
    myIL.Emit(OpCodes.Ldstr, "are three bananas");
    myIL.Emit(OpCodes.Br_S, endOfMethod);

    // Case arg0 = 4
    myIL.MarkLabel(jumpTable[4]);
    myIL.Emit(OpCodes.Ldstr, "are four bananas");
    myIL.Emit(OpCodes.Br_S, endOfMethod);

    // Default case
    myIL.MarkLabel(defaultCase);
    myIL.Emit(OpCodes.Ldstr, "are many bananas");

    myIL.MarkLabel(endOfMethod);
    myIL.Emit(OpCodes.Ret);
    
    return myTypeBuilder.CreateType();
   }

   public static void Main()
   {
    Type myType = BuildMyType();
    
    Console.Write("Enter an integer between 0 and 5: ");
    int theValue = Convert.ToInt32(Console.ReadLine());

    Console.WriteLine("---");
    Object myInstance = Activator.CreateInstance(myType, new object[0]);	
    Console.WriteLine("Yes, there {0} today!", myType.InvokeMember("SwitchMe",
                               BindingFlags.InvokeMethod,
                               null,
                               myInstance,
                               new object[] {theValue}));
   }
}


Imports System.Threading
Imports System.Reflection
Imports System.Reflection.Emit

 _

Class DynamicJumpTableDemo
   
   Public Shared Function BuildMyType() As Type

      Dim myDomain As AppDomain = Thread.GetDomain()
      Dim myAsmName As New AssemblyName()
      myAsmName.Name = "MyDynamicAssembly"
      
      Dim myAsmBuilder As AssemblyBuilder = myDomain.DefineDynamicAssembly(myAsmName, _
                            AssemblyBuilderAccess.Run)
      Dim myModBuilder As ModuleBuilder = myAsmBuilder.DefineDynamicModule("MyJumpTableDemo")
      
      Dim myTypeBuilder As TypeBuilder = myModBuilder.DefineType("JumpTableDemo", _
                                 TypeAttributes.Public)
      Dim myMthdBuilder As MethodBuilder = myTypeBuilder.DefineMethod("SwitchMe", _
                        MethodAttributes.Public Or MethodAttributes.Static, _
                        GetType(String), New Type() {GetType(Integer)})
      
      Dim myIL As ILGenerator = myMthdBuilder.GetILGenerator()
      
      Dim defaultCase As Label = myIL.DefineLabel()
      Dim endOfMethod As Label = myIL.DefineLabel()
      
      ' We are initializing our jump table. Note that the labels
      ' will be placed later using the MarkLabel method. 

      Dim jumpTable() As Label = {myIL.DefineLabel(), _
                  myIL.DefineLabel(), _
                  myIL.DefineLabel(), _
                  myIL.DefineLabel(), _
                  myIL.DefineLabel()}
      
      ' arg0, the number we passed, is pushed onto the stack.
      ' In this case, due to the design of the code sample,
      ' the value pushed onto the stack happens to match the
      ' index of the label (in IL terms, the index of the offset
      ' in the jump table). If this is not the case, such as
      ' when switching based on non-integer values, rules for the correspondence
      ' between the possible case values and each index of the offsets
      ' must be established outside of the ILGenerator.Emit calls,
      ' much as a compiler would.

      myIL.Emit(OpCodes.Ldarg_0)
      myIL.Emit(OpCodes.Switch, jumpTable)
      
      ' Branch on default case
      myIL.Emit(OpCodes.Br_S, defaultCase)
      
      ' Case arg0 = 0
      myIL.MarkLabel(jumpTable(0))
      myIL.Emit(OpCodes.Ldstr, "are no bananas")
      myIL.Emit(OpCodes.Br_S, endOfMethod)
      
      ' Case arg0 = 1
      myIL.MarkLabel(jumpTable(1))
      myIL.Emit(OpCodes.Ldstr, "is one banana")
      myIL.Emit(OpCodes.Br_S, endOfMethod)
      
      ' Case arg0 = 2
      myIL.MarkLabel(jumpTable(2))
      myIL.Emit(OpCodes.Ldstr, "are two bananas")
      myIL.Emit(OpCodes.Br_S, endOfMethod)
      
      ' Case arg0 = 3
      myIL.MarkLabel(jumpTable(3))
      myIL.Emit(OpCodes.Ldstr, "are three bananas")
      myIL.Emit(OpCodes.Br_S, endOfMethod)
      
      ' Case arg0 = 4
      myIL.MarkLabel(jumpTable(4))
      myIL.Emit(OpCodes.Ldstr, "are four bananas")
      myIL.Emit(OpCodes.Br_S, endOfMethod)
      
      ' Default case
      myIL.MarkLabel(defaultCase)
      myIL.Emit(OpCodes.Ldstr, "are many bananas")
      
      myIL.MarkLabel(endOfMethod)
      myIL.Emit(OpCodes.Ret)
      
      Return myTypeBuilder.CreateType()

   End Function 'BuildMyType
    
   
   Public Shared Sub Main()

      Dim myType As Type = BuildMyType()
      
      Console.Write("Enter an integer between 0 and 5: ")
      Dim theValue As Integer = Convert.ToInt32(Console.ReadLine())
      
      Console.WriteLine("---")
      Dim myInstance As [Object] = Activator.CreateInstance(myType, New Object() {})
      Console.WriteLine("Yes, there {0} today!", myType.InvokeMember("SwitchMe", _
                         BindingFlags.InvokeMethod, Nothing, _
                             myInstance, New Object() {theValue}))

   End Sub

End Class

備註

opcode如果參數需要引數，呼叫端必須確定引數長度符合宣告參數的長度。否則，結果將無法預期。例如，如果「發出」指令需要 2 位元組運算元，而呼叫端提供 4 位元組運算元，執行時間會將兩個額外的位元組發出至指令資料流程。這些額外的位元組將會是 Nop 指示。

指令值定義于中 OpCodes 。

適用於

Emit(OpCode, Label)

Source:: ILGenerator.cs

Source:: ILGenerator.cs

Source:: ILGenerator.cs

放置指定的指令到 Microsoft Intermediate Language (MSIL) 資料流中，並留下空間，以便在完成修復時加入標記。

public:
 virtual void Emit(System::Reflection::Emit::OpCode opcode, System::Reflection::Emit::Label label);

public:
 abstract void Emit(System::Reflection::Emit::OpCode opcode, System::Reflection::Emit::Label label);

public virtual void Emit (System.Reflection.Emit.OpCode opcode, System.Reflection.Emit.Label label);

public abstract void Emit (System.Reflection.Emit.OpCode opcode, System.Reflection.Emit.Label label);

abstract member Emit : System.Reflection.Emit.OpCode * System.Reflection.Emit.Label -> unit
override this.Emit : System.Reflection.Emit.OpCode * System.Reflection.Emit.Label -> unit

abstract member Emit : System.Reflection.Emit.OpCode * System.Reflection.Emit.Label -> unit

Public Overridable Sub Emit (opcode As OpCode, label As Label)

Public MustOverride Sub Emit (opcode As OpCode, label As Label)

參數

opcode: OpCode

要在資料流中發出的 MSIL 指令。

label: Label

標記，要從這個位置分支至的。

範例

下列程式碼範例說明如何使用 jump 資料表建立動態方法。跳躍資料表是使用的 Label 陣列所建置。

using namespace System;
using namespace System::Threading;
using namespace System::Reflection;
using namespace System::Reflection::Emit;
Type^ BuildMyType()
{
   AppDomain^ myDomain = Thread::GetDomain();
   AssemblyName^ myAsmName = gcnew AssemblyName;
   myAsmName->Name = "MyDynamicAssembly";
   AssemblyBuilder^ myAsmBuilder = myDomain->DefineDynamicAssembly( myAsmName, AssemblyBuilderAccess::Run );
   ModuleBuilder^ myModBuilder = myAsmBuilder->DefineDynamicModule( "MyJumpTableDemo" );
   TypeBuilder^ myTypeBuilder = myModBuilder->DefineType( "JumpTableDemo", TypeAttributes::Public );
   array<Type^>^temp0 = {int::typeid};
   MethodBuilder^ myMthdBuilder = myTypeBuilder->DefineMethod( "SwitchMe", static_cast<MethodAttributes>(MethodAttributes::Public | MethodAttributes::Static), String::typeid, temp0 );
   ILGenerator^ myIL = myMthdBuilder->GetILGenerator();
   Label defaultCase = myIL->DefineLabel();
   Label endOfMethod = myIL->DefineLabel();
   
   // We are initializing our jump table. Note that the labels
   // will be placed later using the MarkLabel method.
   array<Label>^jumpTable = gcnew array<Label>(5);
   jumpTable[ 0 ] = myIL->DefineLabel();
   jumpTable[ 1 ] = myIL->DefineLabel();
   jumpTable[ 2 ] = myIL->DefineLabel();
   jumpTable[ 3 ] = myIL->DefineLabel();
   jumpTable[ 4 ] = myIL->DefineLabel();
   
   // arg0, the number we passed, is pushed onto the stack.
   // In this case, due to the design of the code sample,
   // the value pushed onto the stack happens to match the
   // index of the label (in IL terms, the index of the offset
   // in the jump table). If this is not the case, such as
   // when switching based on non-integer values, rules for the correspondence
   // between the possible case values and each index of the offsets
   // must be established outside of the ILGenerator::Emit calls,
   // much as a compiler would.
   myIL->Emit( OpCodes::Ldarg_0 );
   myIL->Emit( OpCodes::Switch, jumpTable );
   
   // Branch on default case
   myIL->Emit( OpCodes::Br_S, defaultCase );
   
   // Case arg0 = 0
   myIL->MarkLabel( jumpTable[ 0 ] );
   myIL->Emit( OpCodes::Ldstr, "are no bananas" );
   myIL->Emit( OpCodes::Br_S, endOfMethod );
   
   // Case arg0 = 1
   myIL->MarkLabel( jumpTable[ 1 ] );
   myIL->Emit( OpCodes::Ldstr, "is one banana" );
   myIL->Emit( OpCodes::Br_S, endOfMethod );
   
   // Case arg0 = 2
   myIL->MarkLabel( jumpTable[ 2 ] );
   myIL->Emit( OpCodes::Ldstr, "are two bananas" );
   myIL->Emit( OpCodes::Br_S, endOfMethod );
   
   // Case arg0 = 3
   myIL->MarkLabel( jumpTable[ 3 ] );
   myIL->Emit( OpCodes::Ldstr, "are three bananas" );
   myIL->Emit( OpCodes::Br_S, endOfMethod );
   
   // Case arg0 = 4
   myIL->MarkLabel( jumpTable[ 4 ] );
   myIL->Emit( OpCodes::Ldstr, "are four bananas" );
   myIL->Emit( OpCodes::Br_S, endOfMethod );
   
   // Default case
   myIL->MarkLabel( defaultCase );
   myIL->Emit( OpCodes::Ldstr, "are many bananas" );
   myIL->MarkLabel( endOfMethod );
   myIL->Emit( OpCodes::Ret );
   return myTypeBuilder->CreateType();
}

int main()
{
   Type^ myType = BuildMyType();
   Console::Write( "Enter an integer between 0 and 5: " );
   int theValue = Convert::ToInt32( Console::ReadLine() );
   Console::WriteLine( "---" );
   Object^ myInstance = Activator::CreateInstance( myType, gcnew array<Object^>(0) );
   array<Object^>^temp1 = {theValue};
   Console::WriteLine( "Yes, there {0} today!", myType->InvokeMember( "SwitchMe", BindingFlags::InvokeMethod, nullptr, myInstance, temp1 ) );
}

using System;
using System.Threading;
using System.Reflection;
using System.Reflection.Emit;

class DynamicJumpTableDemo
{
   public static Type BuildMyType()
   {
    AppDomain myDomain = Thread.GetDomain();
    AssemblyName myAsmName = new AssemblyName();
    myAsmName.Name = "MyDynamicAssembly";

    AssemblyBuilder myAsmBuilder = myDomain.DefineDynamicAssembly(
                        myAsmName,
                        AssemblyBuilderAccess.Run);
    ModuleBuilder myModBuilder = myAsmBuilder.DefineDynamicModule(
                        "MyJumpTableDemo");

    TypeBuilder myTypeBuilder = myModBuilder.DefineType("JumpTableDemo",
                            TypeAttributes.Public);
    MethodBuilder myMthdBuilder = myTypeBuilder.DefineMethod("SwitchMe",
                             MethodAttributes.Public |
                             MethodAttributes.Static,
                                             typeof(string),
                                             new Type[] {typeof(int)});

    ILGenerator myIL = myMthdBuilder.GetILGenerator();

    Label defaultCase = myIL.DefineLabel();	
    Label endOfMethod = myIL.DefineLabel();	

    // We are initializing our jump table. Note that the labels
    // will be placed later using the MarkLabel method.

    Label[] jumpTable = new Label[] { myIL.DefineLabel(),
                      myIL.DefineLabel(),
                      myIL.DefineLabel(),
                      myIL.DefineLabel(),
                      myIL.DefineLabel() };

    // arg0, the number we passed, is pushed onto the stack.
    // In this case, due to the design of the code sample,
    // the value pushed onto the stack happens to match the
    // index of the label (in IL terms, the index of the offset
    // in the jump table). If this is not the case, such as
    // when switching based on non-integer values, rules for the correspondence
    // between the possible case values and each index of the offsets
    // must be established outside of the ILGenerator.Emit calls,
    // much as a compiler would.

    myIL.Emit(OpCodes.Ldarg_0);
    myIL.Emit(OpCodes.Switch, jumpTable);
    
    // Branch on default case
    myIL.Emit(OpCodes.Br_S, defaultCase);

    // Case arg0 = 0
    myIL.MarkLabel(jumpTable[0]);
    myIL.Emit(OpCodes.Ldstr, "are no bananas");
    myIL.Emit(OpCodes.Br_S, endOfMethod);

    // Case arg0 = 1
    myIL.MarkLabel(jumpTable[1]);
    myIL.Emit(OpCodes.Ldstr, "is one banana");
    myIL.Emit(OpCodes.Br_S, endOfMethod);

    // Case arg0 = 2
    myIL.MarkLabel(jumpTable[2]);
    myIL.Emit(OpCodes.Ldstr, "are two bananas");
    myIL.Emit(OpCodes.Br_S, endOfMethod);

    // Case arg0 = 3
    myIL.MarkLabel(jumpTable[3]);
    myIL.Emit(OpCodes.Ldstr, "are three bananas");
    myIL.Emit(OpCodes.Br_S, endOfMethod);

    // Case arg0 = 4
    myIL.MarkLabel(jumpTable[4]);
    myIL.Emit(OpCodes.Ldstr, "are four bananas");
    myIL.Emit(OpCodes.Br_S, endOfMethod);

    // Default case
    myIL.MarkLabel(defaultCase);
    myIL.Emit(OpCodes.Ldstr, "are many bananas");

    myIL.MarkLabel(endOfMethod);
    myIL.Emit(OpCodes.Ret);
    
    return myTypeBuilder.CreateType();
   }

   public static void Main()
   {
    Type myType = BuildMyType();
    
    Console.Write("Enter an integer between 0 and 5: ");
    int theValue = Convert.ToInt32(Console.ReadLine());

    Console.WriteLine("---");
    Object myInstance = Activator.CreateInstance(myType, new object[0]);	
    Console.WriteLine("Yes, there {0} today!", myType.InvokeMember("SwitchMe",
                               BindingFlags.InvokeMethod,
                               null,
                               myInstance,
                               new object[] {theValue}));
   }
}


Imports System.Threading
Imports System.Reflection
Imports System.Reflection.Emit

 _

Class DynamicJumpTableDemo
   
   Public Shared Function BuildMyType() As Type

      Dim myDomain As AppDomain = Thread.GetDomain()
      Dim myAsmName As New AssemblyName()
      myAsmName.Name = "MyDynamicAssembly"
      
      Dim myAsmBuilder As AssemblyBuilder = myDomain.DefineDynamicAssembly(myAsmName, _
                            AssemblyBuilderAccess.Run)
      Dim myModBuilder As ModuleBuilder = myAsmBuilder.DefineDynamicModule("MyJumpTableDemo")
      
      Dim myTypeBuilder As TypeBuilder = myModBuilder.DefineType("JumpTableDemo", _
                                 TypeAttributes.Public)
      Dim myMthdBuilder As MethodBuilder = myTypeBuilder.DefineMethod("SwitchMe", _
                        MethodAttributes.Public Or MethodAttributes.Static, _
                        GetType(String), New Type() {GetType(Integer)})
      
      Dim myIL As ILGenerator = myMthdBuilder.GetILGenerator()
      
      Dim defaultCase As Label = myIL.DefineLabel()
      Dim endOfMethod As Label = myIL.DefineLabel()
      
      ' We are initializing our jump table. Note that the labels
      ' will be placed later using the MarkLabel method. 

      Dim jumpTable() As Label = {myIL.DefineLabel(), _
                  myIL.DefineLabel(), _
                  myIL.DefineLabel(), _
                  myIL.DefineLabel(), _
                  myIL.DefineLabel()}
      
      ' arg0, the number we passed, is pushed onto the stack.
      ' In this case, due to the design of the code sample,
      ' the value pushed onto the stack happens to match the
      ' index of the label (in IL terms, the index of the offset
      ' in the jump table). If this is not the case, such as
      ' when switching based on non-integer values, rules for the correspondence
      ' between the possible case values and each index of the offsets
      ' must be established outside of the ILGenerator.Emit calls,
      ' much as a compiler would.

      myIL.Emit(OpCodes.Ldarg_0)
      myIL.Emit(OpCodes.Switch, jumpTable)
      
      ' Branch on default case
      myIL.Emit(OpCodes.Br_S, defaultCase)
      
      ' Case arg0 = 0
      myIL.MarkLabel(jumpTable(0))
      myIL.Emit(OpCodes.Ldstr, "are no bananas")
      myIL.Emit(OpCodes.Br_S, endOfMethod)
      
      ' Case arg0 = 1
      myIL.MarkLabel(jumpTable(1))
      myIL.Emit(OpCodes.Ldstr, "is one banana")
      myIL.Emit(OpCodes.Br_S, endOfMethod)
      
      ' Case arg0 = 2
      myIL.MarkLabel(jumpTable(2))
      myIL.Emit(OpCodes.Ldstr, "are two bananas")
      myIL.Emit(OpCodes.Br_S, endOfMethod)
      
      ' Case arg0 = 3
      myIL.MarkLabel(jumpTable(3))
      myIL.Emit(OpCodes.Ldstr, "are three bananas")
      myIL.Emit(OpCodes.Br_S, endOfMethod)
      
      ' Case arg0 = 4
      myIL.MarkLabel(jumpTable(4))
      myIL.Emit(OpCodes.Ldstr, "are four bananas")
      myIL.Emit(OpCodes.Br_S, endOfMethod)
      
      ' Default case
      myIL.MarkLabel(defaultCase)
      myIL.Emit(OpCodes.Ldstr, "are many bananas")
      
      myIL.MarkLabel(endOfMethod)
      myIL.Emit(OpCodes.Ret)
      
      Return myTypeBuilder.CreateType()

   End Function 'BuildMyType
    
   
   Public Shared Sub Main()

      Dim myType As Type = BuildMyType()
      
      Console.Write("Enter an integer between 0 and 5: ")
      Dim theValue As Integer = Convert.ToInt32(Console.ReadLine())
      
      Console.WriteLine("---")
      Dim myInstance As [Object] = Activator.CreateInstance(myType, New Object() {})
      Console.WriteLine("Yes, there {0} today!", myType.InvokeMember("SwitchMe", _
                         BindingFlags.InvokeMethod, Nothing, _
                             myInstance, New Object() {theValue}))

   End Sub

End Class

備註

指令值定義于列舉中 OpCodes 。

標籤是使用 DefineLabel 建立的，而且其資料流程內的位置是使用 MarkLabel 來修正的。如果使用單一位元組指令，標籤最多可以代表資料流程 127 個位元組的跳躍。 opcode 必須代表分支指令。因為分支是相對指示， label 所以會在修正程式期間，以分支的正確位移取代。

適用於