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Type.MakeArrayType Method ()

Note: This method is new in the .NET Framework version 2.0.

Returns a Type object representing a one-dimensional array of the current type, with a lower bound of zero.

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

'Declaration
Public Overridable Function MakeArrayType As Type
'Usage
Dim instance As Type
Dim returnValue As Type

returnValue = instance.MakeArrayType
public Type MakeArrayType ()
public function MakeArrayType () : Type

Return Value

A Type object representing a one-dimensional array of the current type, with a lower bound of zero.

The MakeArrayType method provides a way to generate array types whose element types are computed at run time.

NoteNote

The common language runtime makes a distinction between vectors —one-dimensional arrays that are always zero-based — and multidimensional arrays. This method overload is the only way to create a vector type. You cannot use the MakeArrayType(Int32) method overload to create vector types.

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

Imports System
Imports System.Reflection
Imports Microsoft.VisualBasic

Public Class Example
    Public Shared Sub Main()
        ' Create a Type object that represents a one-dimensional
        ' array of Example objects.
        Dim t As Type = GetType(Example).MakeArrayType()
        Console.WriteLine(vbCrLf & "Array of Example: " & t.ToString())

        ' Create a Type object that represents a two-dimensional
        ' array of Example objects.
        t = GetType(Example).MakeArrayType(2)
        Console.WriteLine(vbCrLf & "Two-dimensional array of Example: " & t.ToString())

        ' Demonstrate an exception when an invalid array rank is
        ' specified.
        Try
            t = GetType(Example).MakeArrayType(-1)
        Catch ex As Exception
            Console.WriteLine(vbCrLf & ex.ToString())
        End Try

        ' Create a Type object that represents a ByRef parameter
        ' of type Example.
        t = GetType(Example).MakeByRefType()
        Console.WriteLine(vbCrLf & "ByRef Example: " & t.ToString())

        ' 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.
        Dim t2 As Type = GetType(Example)
        Dim mi As MethodInfo = t2.GetMethod("Test")
        Dim pi As ParameterInfo = mi.GetParameters()(0)
        Dim pt As Type = pi.ParameterType
        Console.WriteLine("Are the ByRef types equal? " & (t Is pt))

        ' Create a Type object that represents a pointer to an
        ' Example object.
        t = GetType(Example).MakePointerType()
        Console.WriteLine(vbCrLf & "Pointer to Example: " & t.ToString())
    End Sub

    ' A sample method with a ByRef parameter.
    '
    Public Sub Test(ByRef e As Example)
    End Sub
End Class

' 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*

import System.*;
import System.Reflection.*;

public class Example
{
    public static void main(String[] args)
    {
        // Create a Type object that represents a one-dimensional
        // array of Example objects.
        Type t = Example.class.ToType().MakeArrayType();
        Console.WriteLine("\r\nArray of Example: {0}", t);
        // Create a Type object that represents a two-dimensional
        // array of Example objects.
        t = Example.class.ToType().MakeArrayType(2);
        Console.WriteLine("\r\nTwo-dimensional array of Example: {0}", t);
        // Demonstrate an exception when an invalid array rank is
        // specified.
        try {
            t = Example.class.ToType().MakeArrayType(-1);
        }
        catch (System.Exception ex) {
            Console.WriteLine("\r\n{0}", ex);
        }
        // Create a Type object that represents a ByRef parameter
        // of type Example.
        t = Example.class.ToType().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 = Example.class.ToType();
        MethodInfo mi = t2.GetMethod("Test");
        ParameterInfo pi = mi.GetParameters()[0];
        Type pt = pi.get_ParameterType();
        Console.WriteLine("Are the ByRef types equal? {0}", new 
            Boolean(t == pt));
        // Create a Type object that represents a pointer to an
        // Example object.
        t = Example.class.ToType().MakePointerType();
        Console.WriteLine("\r\nPointer to Example: {0}", t);
    } //main

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

/* 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.jsl:line 2999
   at Example.main()

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

Pointer to Example: Example*

 */

Windows 98, Windows 2000 SP4, Windows Millennium Edition, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter Edition

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

.NET Framework

Supported in: 2.0

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