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TypeBuilder.DefineTypeInitializer Method

Defines the initializer for this type.

Namespace:  System.Reflection.Emit
Assembly:  mscorlib (in mscorlib.dll)

public ConstructorBuilder DefineTypeInitializer()

Return Value

Type: System.Reflection.Emit.ConstructorBuilder
Returns a type initializer.


The containing type has been previously created using CreateType.

The initializer created is always public.

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

public class MyApplication
   public static void Main()
      // Create the "HelloWorld" class
      TypeBuilder helloWorldClass = CreateCallee(Thread.GetDomain());
      Console.WriteLine("Full Name : " + helloWorldClass.FullName);
      Console.WriteLine("Constructors :");
      ConstructorInfo[] info =
      for(int index=0; index < info.Length; index++)

   // Create the callee transient dynamic assembly.
   private static TypeBuilder CreateCallee(AppDomain myDomain)
      AssemblyName myAssemblyName = new AssemblyName();
      myAssemblyName.Name = "EmittedAssembly";

      // Create the callee dynamic assembly.
      AssemblyBuilder myAssembly = myDomain.DefineDynamicAssembly(myAssemblyName,
      // 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", typeof(String),

      // 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();
      ConstructorInfo superConstructor = typeof(Object).GetConstructor(new Type[0]);
      constructorIL.Emit(OpCodes.Call, superConstructor);
      constructorIL.Emit(OpCodes.Stfld, greetingField);


.NET Framework

Supported in: 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.