Type.MakeArrayType Method

Definition

Namespace:

System

Assembly:

System.Runtime.dll

Returns a Type object that represents an array of the current type.

Overloads

MakeArrayType()	Returns a Type object representing a one-dimensional array of the current type, with a lower bound of zero.
MakeArrayType(Int32)	Returns a Type object representing an array of the current type, with the specified number of dimensions.

Examples

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

using namespace System;
using namespace System::Reflection;

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

   // A sample method with a ByRef parameter.
   //
   void Test( interior_ptr<Example^> /*e*/ )
   {
   }
};

int main()
{
   Example::Main();
}

/* 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*

 */

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*

 */

type Example() =
    // A sample method with a ByRef parameter.
    member _.Test(e: Example byref) = ()

do
    // Create a Type object that represents a one-dimensional
    // array of Example objects.
    let t = typeof<Example>.MakeArrayType()
    printfn $"\r\nArray of Example: {t}"

    // Create a Type object that represents a two-dimensional
    // array of Example objects.
    let t = typeof<Example>.MakeArrayType 2
    printfn $"\r\nTwo-dimensional array of Example: {t}"

    // Demonstrate an exception when an invalid array rank is
    // specified.
    try
        let t = typeof<Example>.MakeArrayType -1
        ()
    with ex ->
        printfn $"\r\n{ex}"

    // Create a Type object that represents a ByRef parameter
    // of type Example.
    let t = typeof<Example>.MakeByRefType()
    printfn $"\r\nByRef Example: {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.
    let t2 = typeof<Example>
    let mi = t2.GetMethod "Test"
    let pi = mi.GetParameters()[0]
    let pt = pi.ParameterType
    printfn $"Are the ByRef types equal? {t = pt}"

    // Create a Type object that represents a pointer to an
    // Example object.
    let t = typeof<Example>.MakePointerType()
    printfn $"\r\nPointer to Example: {t}"

(* 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*
 *)

Imports System.Reflection

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*

MakeArrayType()

Source:

Type.cs

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

public:
 virtual Type ^ MakeArrayType();

public virtual Type MakeArrayType ();

abstract member MakeArrayType : unit -> Type
override this.MakeArrayType : unit -> Type

Public Overridable Function MakeArrayType () As Type

Returns

Type

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

Exceptions

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, 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's the only way to create a vector type. Use the MakeArrayType(Int32) method overload to create multidimensional array types.

See also

• MakeByRefType()
• MakePointerType()

MakeArrayType(Int32)

Source:

Type.cs

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

public:
 virtual Type ^ MakeArrayType(int rank);

public virtual Type MakeArrayType (int rank);

abstract member MakeArrayType : int -> Type
override this.MakeArrayType : int -> Type

Public Overridable Function MakeArrayType (rank As Integer) As Type

Parameters

rank

Int32

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

Returns

Type

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

Exceptions

IndexOutOfRangeException

rank is invalid. For example, 0 or negative.

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, IsByRef returns true.

-or-

rank is greater than 32.

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. 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.

See also

• MakeByRefType()
• MakePointerType()