TypeBuilder.MakeGenericType Method

Substitutes the elements of an array of types for the type parameters of the current generic type definition, and returns the resulting constructed type.

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

public override Type MakeGenericType(
	params Type[] typeArguments


Type: System.Type[]
An array of types to be substituted for the type parameters of the current generic type definition.

Return Value

Type: System.Type
The constructed type formed by substituting the elements of typeArguments for the type parameters of the current generic type.


The current type does not represent the definition of a generic type. That is, IsGenericTypeDefinition returns false.


typeArguments is null.


Any element of typeArguments is null.


Any element of typeArguments does not satisfy the constraints specified for the corresponding type parameter of the current generic type.

Use this method when your emitted code requires a type constructed from the current generic type definition. It is not necessary to call the CreateType method before calling the MakeGenericType method on a TypeBuilder that represents a generic type definition. If the current TypeBuilder does not represent the definition of a generic type, an InvalidOperationException is thrown.

The object returned by this method functions as a placeholder for a constructed generic type in your emitted code. It is an instance of a class derived from Type that has limited capabilities. In particular:

  • To get methods, fields, and constructors for these constructed generic types, use the GetMethod(Type, MethodInfo), GetField(Type, FieldInfo), and GetConstructor(Type, ConstructorInfo) method overloads.

  • Two instances that represent the same constructed type do not compare as equal. For example, in the following code t1.Equals(t2) returns false:

    Dim t1 As Type = tbldr.MakeGenericType(GetType(String))
    Dim t2 As Type = tbldr.MakeGenericType(GetType(String))
    Dim result As Boolean = t1.Equals(t2)

    Type t1 = tbldr.MakeGenericType(typeof(string));
    Type t2 = tbldr.MakeGenericType(typeof(string));
    bool result = t1.Equals(t2);


Supported in: 5, 4, 3

For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.

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