TypeBuilder.DefineTypeInitializer Method

Definition

Namespace:

System.Reflection.Emit

Assembly:

System.Reflection.Emit.dll

Source:

TypeBuilder.cs

Defines the initializer for this type.

public:
 System::Reflection::Emit::ConstructorBuilder ^ DefineTypeInitializer();

public System.Reflection.Emit.ConstructorBuilder DefineTypeInitializer ();

member this.DefineTypeInitializer : unit -> System.Reflection.Emit.ConstructorBuilder

Public Function DefineTypeInitializer () As ConstructorBuilder

Returns

ConstructorBuilder

Returns a type initializer.

Exceptions

InvalidOperationException

The containing type has been previously created using CreateType().

Examples

The following code sample demonstrates how to create an initialization constructor using DefineTypeInitializer.

// Create the callee transient dynamic assembly.
TypeBuilder^ CreateCallee( AppDomain^ myDomain )
{
   AssemblyName^ myAssemblyName = gcnew AssemblyName;
   myAssemblyName->Name = "EmittedAssembly";
   
   // Create the callee dynamic assembly.
   AssemblyBuilder^ myAssembly = myDomain->DefineDynamicAssembly( myAssemblyName, AssemblyBuilderAccess::Run );
   
   // Create a dynamic module named "CalleeModule" in the callee assembly.
   ModuleBuilder^ myModule = myAssembly->DefineDynamicModule( "EmittedModule" );
   
   // Define a public class named "HelloWorld" in the assembly.
   TypeBuilder^ helloWorldClass = myModule->DefineType( "HelloWorld", TypeAttributes::Public );
   
   // Define a private String field named "Greeting" in the type.
   FieldBuilder^ greetingField = helloWorldClass->DefineField( "Greeting", String::typeid, FieldAttributes::Private );
   
   // Create the constructor.
   ConstructorBuilder^ constructor = helloWorldClass->DefineTypeInitializer();
   
   // Generate IL for the method. The constructor calls its base class
   // constructor. The constructor stores its argument in the private field.
   ILGenerator^ constructorIL = constructor->GetILGenerator();
   constructorIL->Emit( OpCodes::Ldarg_0 );
   ConstructorInfo^ superConstructor = Object::typeid->GetConstructor( gcnew array<Type^>(0) );
   constructorIL->Emit( OpCodes::Call, superConstructor );
   constructorIL->Emit( OpCodes::Ldarg_0 );
   constructorIL->Emit( OpCodes::Ldarg_1 );
   constructorIL->Emit( OpCodes::Stfld, greetingField );
   constructorIL->Emit( OpCodes::Ret );
   helloWorldClass->CreateType();
   return (helloWorldClass);
}

int main()
{
   // Create the "HelloWorld" class
   TypeBuilder^ helloWorldClass = CreateCallee( Thread::GetDomain() );
   Console::WriteLine( "Full Name : {0}", helloWorldClass->FullName );
   Console::WriteLine( "Constructors :" );
   array<ConstructorInfo^>^info = helloWorldClass->GetConstructors( static_cast<BindingFlags>(BindingFlags::Public | BindingFlags::Instance) );
   for ( int index = 0; index < info->Length; index++ )
      Console::WriteLine( info[ index ] );
}

public class MyApplication
{
   public static void Main()
   {
      // Create the "HelloWorld" class
      Type helloWorldType = CreateType();
      Console.WriteLine("Full Name : " + helloWorldType.FullName);
      Console.WriteLine("Static constructors:");
      ConstructorInfo[] info =
         helloWorldType.GetConstructors(BindingFlags.Static | BindingFlags.NonPublic);
      for(int index=0; index < info.Length; index++)
         Console.WriteLine(info[index].ToString());
      
      // Print value stored in the static field
      Console.WriteLine(helloWorldType.GetField("Greeting").GetValue(null)); 
      Activator.CreateInstance(helloWorldType);
   }

   // Create the dynamic type.
   private static Type CreateType()
   {
      AssemblyName myAssemblyName = new AssemblyName();
      myAssemblyName.Name = "EmittedAssembly";

      // Create the callee dynamic assembly.
      AssemblyBuilder myAssembly = AssemblyBuilder.DefineDynamicAssembly(myAssemblyName,
         AssemblyBuilderAccess.Run);
      // Create a dynamic module named "CalleeModule" in the callee assembly.
      ModuleBuilder myModule = myAssembly.DefineDynamicModule("EmittedModule");

      // Define a public class named "HelloWorld" in the assembly.
      TypeBuilder helloWorldClass = myModule.DefineType("HelloWorld", TypeAttributes.Public);
      // Define a public static string field named "Greeting" in the type.
      FieldBuilder greetingField = helloWorldClass.DefineField("Greeting", typeof(String),
         FieldAttributes.Static | FieldAttributes.Public);

      // Create the static constructor.
      ConstructorBuilder constructor = helloWorldClass.DefineTypeInitializer();

      // Generate IL for the method. 
      // The constructor stores its "Hello emit!" in the public field.
      ILGenerator constructorIL = constructor.GetILGenerator();

      constructorIL.Emit(OpCodes.Ldstr, "Hello emit!");
      constructorIL.Emit(OpCodes.Stsfld, greetingField);      
      constructorIL.Emit(OpCodes.Ret);

      return helloWorldClass.CreateType();
   }
}

Public Class MyApplication

   Public Shared Sub Main()
      ' Create the "HelloWorld" class
      Dim helloWorldClass As TypeBuilder = CreateCallee(Thread.GetDomain())
      Console.WriteLine("Full Name : " + helloWorldClass.FullName)
      Console.WriteLine("Constructors :")
      Dim info As ConstructorInfo() = helloWorldClass.GetConstructors(BindingFlags.Public Or _
                                                                     BindingFlags.Instance)
      Dim index As Integer
      For index = 0 To info.Length - 1
         Console.WriteLine(info(index).ToString())
      Next index
   End Sub

   ' Create the callee transient dynamic assembly.
   Private Shared Function CreateCallee(myDomain As AppDomain) As TypeBuilder
      Dim myAssemblyName As New AssemblyName()
      myAssemblyName.Name = "EmittedAssembly"

      ' Create the callee dynamic assembly.
      Dim myAssembly As AssemblyBuilder = myDomain.DefineDynamicAssembly(myAssemblyName, _
                                                               AssemblyBuilderAccess.Run)
      ' Create a dynamic module named "CalleeModule" in the callee assembly.
      Dim myModule As ModuleBuilder = myAssembly.DefineDynamicModule("EmittedModule")

      ' Define a public class named "HelloWorld" in the assembly.
      Dim helloWorldClass As TypeBuilder = myModule.DefineType("HelloWorld", TypeAttributes.Public)
      ' Define a private String field named "Greeting" in the type.
      Dim greetingField As FieldBuilder = helloWorldClass.DefineField("Greeting", GetType(String), _
                                                                     FieldAttributes.Private)

      ' Create the constructor.
      Dim constructor As ConstructorBuilder = helloWorldClass.DefineTypeInitializer()

      ' Generate IL for the method. The constructor calls its base class
      ' constructor. The constructor stores its argument in the private field.
      Dim constructorIL As ILGenerator = constructor.GetILGenerator()
      constructorIL.Emit(OpCodes.Ldarg_0)
      Dim superConstructor As ConstructorInfo = GetType(Object).GetConstructor(New Type() {})
      constructorIL.Emit(OpCodes.Call, superConstructor)
      constructorIL.Emit(OpCodes.Ldarg_0)
      constructorIL.Emit(OpCodes.Ldarg_1)
      constructorIL.Emit(OpCodes.Stfld, greetingField)
      constructorIL.Emit(OpCodes.Ret)

      helloWorldClass.CreateType()
      Return helloWorldClass
   End Function 'CreateCallee
End Class

Remarks

The initializer created is always public.