Type.MakeArrayType Method (Int32)


Returns a Type object representing an array of the current type, with the specified number of dimensions.

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

Public Overridable Function MakeArrayType (
	rank As Integer
) As Type


Type: System.Int32

The number of dimensions for the array. This number must be less than or equal to 32.

Return Value

Type: System.Type

An object representing an array of the current type, with the specified number of dimensions.

Exception Condition

rank is invalid. For example, 0 or negative.


The invoked method is not supported in the base class.


The current type is TypedReference.


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


rank is greater than 32.

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


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. You cannot use this method overload to create a vector type; if rank is 1, this method overload returns a multidimensional array type that happens to have one dimension. Use the MakeArrayType() 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.
            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*

Universal Windows Platform
Available since 8
.NET Framework
Available since 2.0
Portable Class Library
Supported in: portable .NET platforms
Available since 2.0
Windows Phone Silverlight
Available since 7.0
Windows Phone
Available since 8.1
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