MakeArrayType Method
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Type.MakeArrayType Method

[ This article is for Windows Phone 8 developers. If you’re developing for Windows 10, see the latest documentation. ]

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)

Public Overridable Function MakeArrayType As Type

Return Value

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


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


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

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.

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

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.
         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*

Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

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