Article
11/18/2011

Type.MakeArrayType Method

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Updated: June 2010

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)

Syntax

'Declaration
Public Overridable Function MakeArrayType As Type

public virtual Type MakeArrayType()

Return Value

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

Exceptions

Exception	Condition
NotSupportedException	The invoked method is not supported in the base class. Derived classes must provide an implementation.
TypeLoadException	The current type is TypedReference. -or- The current type is a ByRef type. That is, Type.IsByRef returns true.

NotSupportedException

The invoked method is not supported in the base class. Derived classes must provide an implementation.

TypeLoadException

The current type is TypedReference.

-or-

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

Remarks

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

Note The common language runtime makes a distinction between vectors (that is, one-dimensional arrays that are always zero-based) and multidimensional arrays. A vector, which always has only one dimension, is not the same as a multidimensional array that happens to have only one dimension. This method overload can only be used to create vector types, and it is the only way to create a vector type. Use the MakeArrayType(Int32) method overload to create multidimensional array types.

Examples

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

Note:
To run this example, see Building Examples That Use a Demo Method and a TextBlock Control.

Imports System.Reflection

Public Class Example
   Public Shared Sub Demo(ByVal outputBlock As System.Windows.Controls.TextBlock)
      ' Create a Type object that represents a one-dimensional
      ' array of Example objects.
      Dim t As Type = GetType(Example).MakeArrayType()
      outputBlock.Text &= vbCrLf & "Array of Example: " & t.ToString() & vbCrLf

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

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

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

      ' 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
      outputBlock.Text &= "Are the ByRef types equal? " & (t Is pt) & vbCrLf

      ' Create a Type object that represents a pointer to an
      ' Example object.
      t = GetType(Example).MakePointerType()
      outputBlock.Text &= vbCrLf & "Pointer to Example: " & t.ToString() & vbCrLf
   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: SilverlightApplication.Example[]
'
'Two-dimensional array of Example: SilverlightApplication.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 SilverlightApplication.Example.Demo(TextBlock outputBlock)
'
'ByRef Example: SilverlightApplication.Example&
'Are the ByRef types equal? True
'
'Pointer to Example: SilverlightApplication.Example*

using System;
using System.Reflection;

public class Example
{
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      // Create a Type object that represents a one-dimensional
      // array of Example objects.
      Type t = typeof(Example).MakeArrayType();
      outputBlock.Text += String.Format("\r\nArray of Example: {0}\n", t);

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

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

      // Create a Type object that represents a ByRef parameter
      // of type Example.
      t = typeof(Example).MakeByRefType();
      outputBlock.Text += String.Format("\r\nByRef Example: {0}\n", 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;
      outputBlock.Text += String.Format("Are the ByRef types equal? {0}\n", (t == pt));

      // Create a Type object that represents a pointer to an
      // Example object.
      t = typeof(Example).MakePointerType();
      outputBlock.Text += String.Format("\r\nPointer to Example: {0}\n", 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.Demo(TextBlock outputBlock)

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

Pointer to Example: Example*

 */

Version Information

Silverlight

Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0

XNA Framework

Supported in: Xbox 360, Windows Phone OS 7.0

Platforms

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

Change History

Date	History	Reason
June 2010	Added missing TypeLoadException exception.	Customer feedback.