Type.IsAssignableFrom Method

Determines whether an instance of the current Type can be assigned from an instance of the specified Type.

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

public virtual bool IsAssignableFrom(
	Type c
)

Parameters

c
Type: System.Type

The Type to compare with the current Type.

Return Value

Type: System.Boolean
true if c and the current Type represent the same type, or if the current Type is in the inheritance hierarchy of c, or if the current Type is an interface that c implements, or if c is a generic type parameter and the current Type represents one of the constraints of c. false if none of these conditions are true, or if c is null.

Implements

_Type.IsAssignableFrom(Type)

This method can be overridden by a derived class.

NoteNote:

A generic type definition is not assignable from a closed constructed type. That is, you cannot assign the closed constructed type MyGenericList<int> (MyGenericList(Of Integer) in Visual Basic) to a variable of type MyGenericList<T>.

You can determine the element types of a Type using GetElementType.

If the c parameter is of type TypeBuilder, the result is based on the type that is to be built. The following code example demonstrates this using a built type named B.

TypeBuilder b1 = moduleBuilder.DefineType("B", TypeAttributes.Public, typeof(A));
// Returns true:
typeof(A).IsAssignableFrom(b1))

The following example demonstrates the IsAssignableFrom method using defined classes, integer arrays, and generics.

using System;
using System.Collections.Generic;
class Program
{
    public static void Main()
    {
            // Demonstrate classes:
            Console.WriteLine("Defned Classes:");
            Room room1 = new Room();
            Kitchen kitchen1 = new Kitchen();
            Bedroom bedroom1 = new Bedroom();
            Guestroom guestroom1 = new Guestroom();
            MasterBedroom masterbedroom1 = new MasterBedroom();

            Type room1Type = room1.GetType();
            Type kitchen1Type = kitchen1.GetType();
            Type bedroom1Type = bedroom1.GetType();
            Type guestroom1Type = guestroom1.GetType();
            Type masterbedroom1Type = masterbedroom1.GetType();

            Console.WriteLine("room assignable from kitchen: {0}", room1Type.IsAssignableFrom(kitchen1Type));
            Console.WriteLine("bedroom assignable from guestroom: {0}", bedroom1Type.IsAssignableFrom(guestroom1Type));
            Console.WriteLine("kitchen assignable from masterbedroom: {0}", kitchen1Type.IsAssignableFrom(masterbedroom1Type));

            // Demonstrate arrays:
            Console.WriteLine();
            Console.WriteLine("Integer arrays:");

            int[] array2 = new int[2];
            int[] array10 = new int[10];
            int[,] array22 = new int[2, 2];
            int[,] array24 = new int[2, 4];

            Type array2Type = array2.GetType();
            Type array10Type = array10.GetType();
            Type array22Type = array22.GetType();
            Type array24Type = array24.GetType();

            Console.WriteLine("int[2] assignable from int[10]: {0}", array2Type.IsAssignableFrom(array10Type));
            Console.WriteLine("int[2] assignable from int[2,4]: {0}", array2Type.IsAssignableFrom(array24Type));
            Console.WriteLine("int[2,4] assignable from int[2,2]: {0}", array24Type.IsAssignableFrom(array22Type));

            // Demonstrate generics:
            Console.WriteLine();
            Console.WriteLine("Generics:");

            // Note that "int?[]" is the same as "Nullable<int>[]" 
            int?[] arrayNull = new int?[10];
            List<int> genIntList = new List<int>();
            List<Type> genTList = new List<Type>();

            Type arrayNullType = arrayNull.GetType();
            Type genIntListType = genIntList.GetType();
            Type genTListType = genTList.GetType();

            Console.WriteLine("int[10] assignable from int?[10]: {0}", array10Type.IsAssignableFrom(arrayNullType));
            Console.WriteLine("List<int> assignable from List<Type>: {0}", genIntListType.IsAssignableFrom(genTListType));
            Console.WriteLine("List<Type> assignable from List<int>: {0}", genTListType.IsAssignableFrom(genIntListType));

            Console.ReadLine();

    }
}
class Room
{
}

class Kitchen : Room
{
}

class Bedroom : Room
{
}

class Guestroom : Bedroom
{
}

class MasterBedroom : Bedroom
{
}

//This code example produces the following output: 
// 
// Defned Classes: 
// room assignable from kitchen: True 
// bedroom assignable from guestroom: True 
// kitchen assignable from masterbedroom: False 
// 
// Integer arrays: 
// int[2] assignable from int[10]: True 
// int[2] assignable from int[2,4]: False 
// int[2,4] assignable from int[2,2]: True 
// 
// Generics: 
// int[10] assignable from int?[10]: False 
// List<int> assignable from List<Type>: False 
// List<Type> assignable from List<int>: False

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

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

.NET Framework

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

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0
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