TypeBuilder::DefineUninitializedData Method (String^, Int32, FieldAttributes)
Defines an uninitialized data field in the .sdata section of the portable executable (PE) file.
Assembly: mscorlib (in mscorlib.dll)
public: FieldBuilder^ DefineUninitializedData( String^ name, int size, FieldAttributes attributes )
Parameters
- name
-
Type:
System::String^
The name used to refer to the data. name cannot contain embedded nulls.
- size
-
Type:
System::Int32
The size of the data field.
- attributes
-
Type:
System.Reflection::FieldAttributes
The attributes for the field.
| Exception | Condition |
|---|---|
| ArgumentException | Length of name is zero. -or- size is less than or equal to zero, or greater than or equal to 0x003f0000. |
| ArgumentNullException | name is null. |
| InvalidOperationException | The type was previously created using CreateType. |
The field that you create with this method will be static, even if you do not include FieldAttributes.Static in the attributes parameter.
The following code sample demonstrates the use of DefineUninitializedData to create an uninitialized data field in a dynamic type:
using namespace System; using namespace System::Threading; using namespace System::Reflection; using namespace System::Reflection::Emit; using namespace System::Runtime::InteropServices; using namespace System::Security::Permissions; public ref class Example { public: [SecurityPermission(SecurityAction::Demand, Flags=SecurityPermissionFlag::UnmanagedCode)] static void Main() { Type^ myHelloWorldType = CreateCallee( Thread::GetDomain() ); Object^ myHelloWorldInstance = Activator::CreateInstance( myHelloWorldType ); FieldInfo^ myGreetingFieldInfo = myHelloWorldType->GetField( "MyGreeting" ); Object^ oval = Activator::CreateInstance( myGreetingFieldInfo->FieldType ); IntPtr myIntPtr = Marshal::AllocHGlobal( 4 ); Random^ rand = gcnew Random; int iTempSeed = rand->Next(); array<Byte>^bINITBYTE = GetRandBytes( iTempSeed, 4 ); IntPtr intptrTemp = myIntPtr; for ( int j = 0; j < 4; j++ ) { Marshal::WriteByte( myIntPtr, bINITBYTE[ j ] ); myIntPtr = (IntPtr)((int)myIntPtr + 1); } myIntPtr = intptrTemp; Object^ oValNew = Marshal::PtrToStructure( myIntPtr, myGreetingFieldInfo->FieldType ); Marshal::FreeHGlobal( myIntPtr ); myIntPtr = Marshal::AllocHGlobal( 4 ); Object^ myObj = myGreetingFieldInfo->GetValue( myHelloWorldInstance ); Marshal::StructureToPtr( myObj, myIntPtr, true ); intptrTemp = myIntPtr; Console::WriteLine( "The value of 'MyGreeting' field : " ); for ( int j = 0; j < 4; j++ ) { Marshal::WriteByte( myIntPtr, bINITBYTE[ j ] ); Console::WriteLine( bINITBYTE[ j ] ); myIntPtr = (IntPtr)((int)myIntPtr + 1); } } private: static array<Byte>^ GetRandBytes( int iRandSeed, int iSize ) { array<Byte>^barr = gcnew array<Byte>(iSize); Random^ randTemp = gcnew Random( iRandSeed ); randTemp->NextBytes( barr ); return barr; } // Create the callee transient dynamic assembly. static Type^ CreateCallee( AppDomain^ myDomain ) { // Create a simple name for the callee assembly. AssemblyName^ myAssemblyName = gcnew AssemblyName; myAssemblyName->Name = "EmittedClass"; // Create the callee dynamic assembly. AssemblyBuilder^ myAssembly = myDomain->DefineDynamicAssembly( myAssemblyName, AssemblyBuilderAccess::Run ); // Create a dynamic module in the callee assembly. ModuleBuilder^ myModule = myAssembly->DefineDynamicModule( "EmittedModule" ); // Define a public class named "MyHelloWorld" TypeBuilder^ myHelloWorldType = myModule->DefineType( "MyHelloWorld", TypeAttributes::Public ); // Define a 'MyGreeting' field and initialize it. FieldBuilder^ myFieldBuilder = myHelloWorldType->DefineUninitializedData( "MyGreeting", 4, FieldAttributes::Public ); // Create the 'MyHelloWorld' class. return (myHelloWorldType->CreateType()); } }; int main() { Example::Main(); }
Available since 1.1
Silverlight
Available since 2.0