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Type.MakeByRefType Method

Returns a Type object that represents the current type when passed as a ref parameter (ByRef parameter in Visual Basic).

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

public virtual Type MakeByRefType()

Return Value

Type: System.Type
A Type object that represents the current type when passed as a ref parameter (ByRef parameter in Visual Basic).

ExceptionCondition
NotSupportedException

The invoked method is not supported in the base class.

TypeLoadException

The current type is TypedReference.

-or-

The current type is a ByRef type. That is, Type.IsByRef returns true.

The MakeByRefType method provides a way to generate ref types (ByRef in Visual Basic) for parameter lists.

Using the syntax of Microsoft intermediate language (MSIL), if the current Type object represents Int32, this method returns a Type object representing Int32&.

The following code example creates array, ref (ByRef in Visual Basic), and pointer types for the Test class.

using System;
using System.Reflection;

public class Example
{
    public static void Main()
    {
        // Create a Type object that represents a one-dimensional 
        // array of Example objects.
        Type t = typeof(Example).MakeArrayType();
        Console.WriteLine("\r\nArray of Example: {0}", t);

        // Create a Type object that represents a two-dimensional 
        // array of Example objects.
        t = typeof(Example).MakeArrayType(2);
        Console.WriteLine("\r\nTwo-dimensional array of Example: {0}", t);

        // Demonstrate an exception when an invalid array rank is 
        // specified. 
        try
        {
            t = typeof(Example).MakeArrayType(-1);
        }
        catch(Exception ex)
        {
            Console.WriteLine("\r\n{0}", ex);
        }

        // Create a Type object that represents a ByRef parameter 
        // of type Example.
        t = typeof(Example).MakeByRefType();
        Console.WriteLine("\r\nByRef Example: {0}", t);

        // Get a Type object representing the Example class, a 
        // MethodInfo representing the "Test" method, a ParameterInfo
        // representing the parameter of type Example, and finally 
        // a Type object representing the type of this ByRef parameter. 
        // Compare this Type object with the Type object created using 
        // MakeByRefType.
        Type t2 = typeof(Example);
        MethodInfo mi = t2.GetMethod("Test");
        ParameterInfo pi = mi.GetParameters()[0];
        Type pt = pi.ParameterType;
        Console.WriteLine("Are the ByRef types equal? {0}", (t == pt));

        // Create a Type object that represents a pointer to an 
        // Example object.
        t = typeof(Example).MakePointerType();
        Console.WriteLine("\r\nPointer to Example: {0}", t);
    }

    // A sample method with a ByRef parameter. 
    // 
    public void Test(ref Example e)
    {
    }
}

/* This example produces output similar to the following:

Array of Example: Example[]

Two-dimensional array of Example: Example[,]

System.IndexOutOfRangeException: Index was outside the bounds of the array.
   at System.RuntimeType.MakeArrayType(Int32 rank) in c:\vbl\ndp\clr\src\BCL\System\RtType.cs:line 2999
   at Example.Main()

ByRef Example: Example&
Are the ByRef types equal? True

Pointer to Example: Example*

 */

.NET Framework

Supported in: 4.6, 4.5, 4, 3.5, 3.0, 2.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

Supported in: Windows Phone 8.1

Supported in: Windows Phone Silverlight 8.1

Supported in: Windows Phone Silverlight 8
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