TypeBuilder.DefineDefaultConstructor(MethodAttributes) Method

Definition

Namespace:

System.Reflection.Emit

Assembly:

System.Reflection.Emit.dll

Source:

TypeBuilder.cs

Defines the parameterless constructor. The constructor defined here will simply call the parameterless constructor of the parent.

public:
 System::Reflection::Emit::ConstructorBuilder ^ DefineDefaultConstructor(System::Reflection::MethodAttributes attributes);

public System.Reflection.Emit.ConstructorBuilder DefineDefaultConstructor (System.Reflection.MethodAttributes attributes);

member this.DefineDefaultConstructor : System.Reflection.MethodAttributes -> System.Reflection.Emit.ConstructorBuilder

Public Function DefineDefaultConstructor (attributes As MethodAttributes) As ConstructorBuilder

Parameters

attributes

MethodAttributes

A MethodAttributes object representing the attributes to be applied to the constructor.

Returns

ConstructorBuilder

Returns the constructor.

Exceptions

NotSupportedException

The parent type (base type) does not have a parameterless constructor.

InvalidOperationException

The type was previously created using CreateType().

-or-

For the current dynamic type, the IsGenericType property is true, but the IsGenericTypeDefinition property is false.

Examples

The following code sample demonstrates the use of DefineConstructor to set a constructor's particular signature and attributes on a dynamic type and return a corresponding ConstructorBuilder for MSIL population.

// Define the constructor.
array<Type^>^ constructorArgs = {String::typeid};
ConstructorBuilder^ myConstructorBuilder =
   helloWorldTypeBuilder->DefineConstructor( MethodAttributes::Public,
      CallingConventions::Standard, constructorArgs );
// Generate IL for the method. The constructor stores its argument in the private field.
ILGenerator^ myConstructorIL = myConstructorBuilder->GetILGenerator();
myConstructorIL->Emit( OpCodes::Ldarg_0 );
myConstructorIL->Emit( OpCodes::Ldarg_1 );
myConstructorIL->Emit( OpCodes::Stfld, myGreetingField );
myConstructorIL->Emit( OpCodes::Ret );

// Define the constructor.
Type[] constructorArgs = { typeof(String) };
ConstructorBuilder myConstructorBuilder =
   helloWorldTypeBuilder.DefineConstructor(MethodAttributes.Public,
                      CallingConventions.Standard, constructorArgs);
// Generate IL for the method. The constructor stores its argument in the private field.
ILGenerator myConstructorIL = myConstructorBuilder.GetILGenerator();
myConstructorIL.Emit(OpCodes.Ldarg_0);
myConstructorIL.Emit(OpCodes.Ldarg_1);
myConstructorIL.Emit(OpCodes.Stfld, myGreetingField);
myConstructorIL.Emit(OpCodes.Ret);

' Define the constructor.
Dim constructorArgs As Type() = {GetType(String)}
Dim myConstructorBuilder As ConstructorBuilder = helloWorldTypeBuilder.DefineConstructor _
                     (MethodAttributes.Public, CallingConventions.Standard, constructorArgs)
' Generate IL for the method. The constructor stores its argument in the private field.
Dim myConstructorIL As ILGenerator = myConstructorBuilder.GetILGenerator()
myConstructorIL.Emit(OpCodes.Ldarg_0)
myConstructorIL.Emit(OpCodes.Ldarg_1)
myConstructorIL.Emit(OpCodes.Stfld, myGreetingField)
myConstructorIL.Emit(OpCodes.Ret)

Remarks

Because the parameterless constructor is automatically defined, it is necessary to call this method only in the following situations:

• You have defined another constructor and you also want a parameterless constructor that simply calls the base class constructor.

• You want to set the attributes on the parameterless constructor to something other than PrivateScope, Public, HideBySig, SpecialName, and RTSpecialName.