Type.MakeArrayType Method

May 11, 2014

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 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.

ExceptionCondition
NotSupportedException

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

TypeLoadException

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.


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*

 */


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Supported in: 8.1, 8.0, 7.1, 7.0

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