TypeBuilder Class
Assembly: mscorlib (in mscorlib.dll)
'Declaration <ClassInterfaceAttribute(ClassInterfaceType.None)> _ <ComVisibleAttribute(True)> _ Public NotInheritable Class TypeBuilder Inherits Type Implements _TypeBuilder 'Usage Dim instance As TypeBuilder
/** @attribute ClassInterfaceAttribute(ClassInterfaceType.None) */ /** @attribute ComVisibleAttribute(true) */ public final class TypeBuilder extends Type implements _TypeBuilder
ClassInterfaceAttribute(ClassInterfaceType.None) ComVisibleAttribute(true) public final class TypeBuilder extends Type implements _TypeBuilder
Note |
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| The HostProtectionAttribute attribute applied to this class has the following Resources property value: MayLeakOnAbort. The HostProtectionAttribute does not affect desktop applications (which are typically started by double-clicking an icon, typing a command, or entering a URL in a browser). For more information, see the HostProtectionAttribute class or SQL Server Programming and Host Protection Attributes. |
TypeBuilder is the root class used to control the creation of dynamic classes in the runtime. TypeBuilder provides a set of routines that are used to define classes, add methods and fields, and create the class inside the runtime. A new TypeBuilder can be created from a dynamic module.
To retrieve a Type object for an incomplete type, use ModuleBuilder.GetType with a string representing the type name, such as "MyType" or "MyType[]".
The following code sample demonstrates how to build a dynamic type using TypeBuilder.
Imports System Imports System.Threading Imports System.Reflection Imports System.Reflection.Emit _ Class TestILGenerator Public Shared Function DynamicDotProductGen() As Type Dim ivType As Type = Nothing Dim ctorParams() As Type = {GetType(Integer), GetType(Integer), GetType(Integer)} Dim myDomain As AppDomain = Thread.GetDomain() Dim myAsmName As New AssemblyName() myAsmName.Name = "IntVectorAsm" Dim myAsmBuilder As AssemblyBuilder = myDomain.DefineDynamicAssembly( _ myAsmName, _ AssemblyBuilderAccess.RunAndSave) Dim IntVectorModule As ModuleBuilder = myAsmBuilder.DefineDynamicModule( _ "IntVectorModule", _ "Vector.dll") Dim ivTypeBld As TypeBuilder = IntVectorModule.DefineType("IntVector", TypeAttributes.Public) Dim xField As FieldBuilder = ivTypeBld.DefineField("x", _ GetType(Integer), _ FieldAttributes.Private) Dim yField As FieldBuilder = ivTypeBld.DefineField("y", _ GetType(Integer), _ FieldAttributes.Private) Dim zField As FieldBuilder = ivTypeBld.DefineField("z", _ GetType(Integer), _ FieldAttributes.Private) Dim objType As Type = Type.GetType("System.Object") Dim objCtor As ConstructorInfo = objType.GetConstructor(New Type() {}) Dim ivCtor As ConstructorBuilder = ivTypeBld.DefineConstructor( _ MethodAttributes.Public, _ CallingConventions.Standard, _ ctorParams) Dim ctorIL As ILGenerator = ivCtor.GetILGenerator() ctorIL.Emit(OpCodes.Ldarg_0) ctorIL.Emit(OpCodes.Call, objCtor) ctorIL.Emit(OpCodes.Ldarg_0) ctorIL.Emit(OpCodes.Ldarg_1) ctorIL.Emit(OpCodes.Stfld, xField) ctorIL.Emit(OpCodes.Ldarg_0) ctorIL.Emit(OpCodes.Ldarg_2) ctorIL.Emit(OpCodes.Stfld, yField) ctorIL.Emit(OpCodes.Ldarg_0) ctorIL.Emit(OpCodes.Ldarg_3) ctorIL.Emit(OpCodes.Stfld, zField) ctorIL.Emit(OpCodes.Ret) ' Now, you'll construct the method find the dot product of two vectors. First, ' let's define the parameters that will be accepted by the method. In this case, ' it's an IntVector itself! Dim dpParams() As Type = {ivTypeBld} ' Here, you create a MethodBuilder containing the ' name, the attributes (public, static, private, and so on), ' the return type (int, in this case), and a array of Type ' indicating the type of each parameter. Since the sole parameter ' is a IntVector, the very class you're creating, you will ' pass in the TypeBuilder (which is derived from Type) instead of ' a Type object for IntVector, avoiding an exception. ' -- This method would be declared in VB.NET as: ' Public Function DotProduct(IntVector aVector) As Integer Dim dotProductMthd As MethodBuilder = ivTypeBld.DefineMethod("DotProduct", _ MethodAttributes.Public, GetType(Integer), _ dpParams) ' A ILGenerator can now be spawned, attached to the MethodBuilder. Dim mthdIL As ILGenerator = dotProductMthd.GetILGenerator() ' Here's the body of our function, in MSIL form. We're going to find the ' "dot product" of the current vector instance with the passed vector ' instance. For reference purposes, the equation is: ' (x1 * x2) + (y1 * y2) + (z1 * z2) = the dot product ' First, you'll load the reference to the current instance "this" ' stored in argument 0 (ldarg.0) onto the stack. Ldfld, the subsequent ' instruction, will pop the reference off the stack and look up the ' field "x", specified by the FieldInfo token "xField". mthdIL.Emit(OpCodes.Ldarg_0) mthdIL.Emit(OpCodes.Ldfld, xField) ' That completed, the value stored at field "x" is now atop the stack. ' Now, you'll do the same for the object reference we passed as a ' parameter, stored in argument 1 (ldarg.1). After Ldfld executed, ' you'll have the value stored in field "x" for the passed instance ' atop the stack. mthdIL.Emit(OpCodes.Ldarg_1) mthdIL.Emit(OpCodes.Ldfld, xField) ' There will now be two values atop the stack - the "x" value for the ' current vector instance, and the "x" value for the passed instance. ' You'll now multiply them, and push the result onto the evaluation stack. mthdIL.Emit(OpCodes.Mul_Ovf_Un) ' Now, repeat this for the "y" fields of both vectors. mthdIL.Emit(OpCodes.Ldarg_0) mthdIL.Emit(OpCodes.Ldfld, yField) mthdIL.Emit(OpCodes.Ldarg_1) mthdIL.Emit(OpCodes.Ldfld, yField) mthdIL.Emit(OpCodes.Mul_Ovf_Un) ' At this time, the results of both multiplications should be atop ' the stack. You'll now add them and push the result onto the stack. mthdIL.Emit(OpCodes.Add_Ovf_Un) ' Multiply both "z" field and push the result onto the stack. mthdIL.Emit(OpCodes.Ldarg_0) mthdIL.Emit(OpCodes.Ldfld, zField) mthdIL.Emit(OpCodes.Ldarg_1) mthdIL.Emit(OpCodes.Ldfld, zField) mthdIL.Emit(OpCodes.Mul_Ovf_Un) ' Finally, add the result of multiplying the "z" fields with the ' result of the earlier addition, and push the result - the dot product - ' onto the stack. mthdIL.Emit(OpCodes.Add_Ovf_Un) ' The "ret" opcode will pop the last value from the stack and return it ' to the calling method. You're all done! mthdIL.Emit(OpCodes.Ret) ivType = ivTypeBld.CreateType() Return ivType End Function 'DynamicDotProductGen Public Shared Sub Main() Dim IVType As Type = Nothing Dim aVector1 As Object = Nothing Dim aVector2 As Object = Nothing Dim aVtypes() As Type = {GetType(Integer), GetType(Integer), GetType(Integer)} Dim aVargs1() As Object = {10, 10, 10} Dim aVargs2() As Object = {20, 20, 20} ' Call the method to build our dynamic class. IVType = DynamicDotProductGen() Dim myDTctor As ConstructorInfo = IVType.GetConstructor(aVtypes) aVector1 = myDTctor.Invoke(aVargs1) aVector2 = myDTctor.Invoke(aVargs2) Console.WriteLine("---") Dim passMe(0) As Object passMe(0) = CType(aVector2, Object) Console.WriteLine("(10, 10, 10) . (20, 20, 20) = {0}", _ IVType.InvokeMember("DotProduct", BindingFlags.InvokeMethod, _ Nothing, aVector1, passMe)) End Sub 'Main End Class 'TestILGenerator ' +++ OUTPUT +++ ' --- ' (10, 10, 10) . (20, 20, 20) = 600
import System.*;
import System.Threading.*;
import System.Reflection.*;
import System.Reflection.Emit.*;
class TestILGenerator
{
public static Type DynamicDotProductGen()
{
Type ivType = null;
Type ctorParams[] = new Type[]{int.class.ToType(),
int.class.ToType(), int.class.ToType()};
AppDomain myDomain = System.Threading.Thread.GetDomain();
AssemblyName myAsmName = new AssemblyName();
myAsmName.set_Name("IntVectorAsm");
AssemblyBuilder myAsmBuilder = myDomain.DefineDynamicAssembly
(myAsmName, AssemblyBuilderAccess.RunAndSave);
ModuleBuilder IntVectorModule = myAsmBuilder.DefineDynamicModule
("IntVectorModule", "Vector.dll");
TypeBuilder ivTypeBld = IntVectorModule.DefineType("IntVector",
TypeAttributes.Public);
FieldBuilder xField = ivTypeBld.DefineField("x",
int.class.ToType(), FieldAttributes.Private);
FieldBuilder yField = ivTypeBld.DefineField("y",
int.class.ToType(), FieldAttributes.Private);
FieldBuilder zField = ivTypeBld.DefineField("z",
int.class.ToType(), FieldAttributes.Private);
Type objType = Type.GetType("System.Object");
ConstructorInfo objCtor = objType.GetConstructor(new Type[0]);
ConstructorBuilder ivCtor =
ivTypeBld.DefineConstructor(MethodAttributes.Public,
CallingConventions.Standard, ctorParams);
ILGenerator ctorIL = ivCtor.GetILGenerator();
ctorIL.Emit(OpCodes.Ldarg_0);
ctorIL.Emit(OpCodes.Call, objCtor);
ctorIL.Emit(OpCodes.Ldarg_0);
ctorIL.Emit(OpCodes.Ldarg_1);
ctorIL.Emit(OpCodes.Stfld, xField);
ctorIL.Emit(OpCodes.Ldarg_0);
ctorIL.Emit(OpCodes.Ldarg_2);
ctorIL.Emit(OpCodes.Stfld, yField);
ctorIL.Emit(OpCodes.Ldarg_0);
ctorIL.Emit(OpCodes.Ldarg_3);
ctorIL.Emit(OpCodes.Stfld, zField);
ctorIL.Emit(OpCodes.Ret);
// This method will find the dot product of the stored vector
// with another.
Type dpParams[] = new Type[]{ivTypeBld};
// Here, you create a MethodBuilder containing the
// name, the attributes (public, static, private, and so on),
// the return type (int, in this case), and a array of Type
// indicating the type of each parameter. Since the sole parameter
// is a IntVector, the very class you're creating, you will
// pass in the TypeBuilder (which is derived from Type) instead of
// a Type object for IntVector, avoiding an exception.
// -- This method would be declared in VJ# as:
// public int DotProduct(IntVector aVector)
MethodBuilder dotProductMthd = ivTypeBld.DefineMethod("DotProduct",
MethodAttributes.Public, int .class.ToType(), dpParams);
// A ILGenerator can now be spawned, attached to the MethodBuilder.
ILGenerator mthdIL = dotProductMthd.GetILGenerator();
// Here's the body of our function, in MSIL form. We're going to
// find the "dot product" of the current vector instance with the
// passed vector instance. For reference purposes, the equation is:
// (x1 * x2) + (y1 * y2) + (z1 * z2) = the dot product
// First, you'll load the reference to the current instance "this"
// stored in argument 0 (ldarg.0) onto the stack. Ldfld, the
// subsequent instruction, will pop the reference off the stack and
// look up the field "x",specified by the FieldInfo token "xField".
mthdIL.Emit(OpCodes.Ldarg_0);
mthdIL.Emit(OpCodes.Ldfld, xField);
// That completed, the value stored at field "x" is now atop the
// stack.Now, you'll do the same for the object reference we passed
// as a parameter, stored in argument 1 (ldarg.1). After Ldfld
// executed,you'll have the value stored in field "x" for the
// passed instance atop the stack.
mthdIL.Emit(OpCodes.Ldarg_1);
mthdIL.Emit(OpCodes.Ldfld, xField);
// There will now be two values atop the stack - the "x" value for
// the current vector instance, and the "x" value for the passed
// instance.You'll now multiply them, and push the result onto the
// evaluation stack.
mthdIL.Emit(OpCodes.Mul_Ovf_Un);
// Now, repeat this for the "y" fields of both vectors.
mthdIL.Emit(OpCodes.Ldarg_0);
mthdIL.Emit(OpCodes.Ldfld, yField);
mthdIL.Emit(OpCodes.Ldarg_1);
mthdIL.Emit(OpCodes.Ldfld, yField);
mthdIL.Emit(OpCodes.Mul_Ovf_Un);
// At this time, the results of both multiplications should be atop
// the stack. You'll now add them and push the result
// onto the stack.
mthdIL.Emit(OpCodes.Add_Ovf_Un);
// Multiply both "z" field and push the result onto the stack.
mthdIL.Emit(OpCodes.Ldarg_0);
mthdIL.Emit(OpCodes.Ldfld, zField);
mthdIL.Emit(OpCodes.Ldarg_1);
mthdIL.Emit(OpCodes.Ldfld, zField);
mthdIL.Emit(OpCodes.Mul_Ovf_Un);
// Finally, add the result of multiplying the "z" fields with the
// result of the earlier addition, and push the result
// - the dot product - onto the stack.
mthdIL.Emit(OpCodes.Add_Ovf_Un);
// The "ret" opcode will pop the last value from the stack and
// return it to the calling method. You're all done!
mthdIL.Emit(OpCodes.Ret);
ivType = ivTypeBld.CreateType();
return ivType ;
} //DynamicDotProductGen
public static void main(String[] args)
{
Type ivType = null;
Object aVector1 = null;
Object aVector2 = null;
Type aVtypes[] = new Type[] {
int.class.ToType(), int.class.ToType(), int.class.ToType()};
Object aVargs1[] = new Object[] { (Int32)10, (Int32)10, (Int32)10};
Object aVargs2[] = new Object[] { (Int32)20, (Int32)20, (Int32)20};
// Call the method to build our dynamic class.
ivType = DynamicDotProductGen();
Console.WriteLine("---");
ConstructorInfo myDTctor = ivType.GetConstructor(aVtypes);
aVector1 = myDTctor.Invoke(aVargs1);
aVector2 = myDTctor.Invoke(aVargs2);
Object passMe[] = new Object[1];
passMe.set_Item(0, ((Object)(aVector2)));
Console.WriteLine("(10, 10, 10) . (20, 20, 20) = {0}",
ivType.InvokeMember("DotProduct", BindingFlags.InvokeMethod,
null, aVector1, passMe));
} //main
} //TestILGenerator
// +++ OUTPUT +++
// ---
// (10, 10, 10) . (20, 20, 20) = 600
Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see System Requirements.
Note