TypeBuilder.DefineTypeInitializer Method

Definition

Namespace:

System.Reflection.Emit

Assemblies:

netstandard.dll, System.Reflection.Emit.dll

Source:

TypeBuilder.cs

Defines the initializer for this type.

C#

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

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.

C#

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();
   }
}

Remarks

The initializer created is always public.

Applies to