ParameterAttributes Enumeration
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ParameterAttributes Enumeration

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

Defines the attributes that can be associated with a parameter. These are defined in CorHdr.h.

This enumeration has a FlagsAttribute attribute that allows a bitwise combination of its member values.

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

[FlagsAttribute]
public enum ParameterAttributes

Member nameDescription
HasDefaultSpecifies that the parameter has a default value.
HasFieldMarshalSpecifies that the parameter has field marshaling information.
InSpecifies that the parameter is an input parameter.
LcidSpecifies that the parameter is a locale identifier. Not supported. Present in Windows Phone.
NoneSpecifies that there is no parameter attribute.
OptionalSpecifies that the parameter is optional.
OutSpecifies that the parameter is an output parameter.
Reserved3Reserved.
Reserved4Reserved.
ReservedMaskSpecifies that the parameter is reserved.
RetvalSpecifies that the parameter is a return value.

To get the ParameterAttributes value, first get the Type. From the Type, get the ParameterInfo array. The ParameterAttributes value is within the array.

These enumerator values are dependent on optional metadata. Not all attributes are available from all compilers. See the appropriate compiler instructions to determine which enumerated values are available.

The following example displays the attributes of four parameters.


using System;
using System.Reflection;
using System.Runtime.InteropServices;

class Example
{
   public static void mymethod(string str1, ref string str2, out string str3,
      [In] string str4)
   {
      // Concatenate str1 to str2, which is ref.
      str2 += str1;
      // When mymethod is called, str3 has no value. Give it one.
      str3 = "new value";
   }

   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
   {
      MethodInfo mm = typeof(Example).GetMethod("mymethod");

      // Display the method.
      outputBlock.Text += "MethodInfo.ToString(): " + mm.ToString() + "\n";

      // Get and display the attributes for the second parameter.
      foreach (ParameterInfo param in mm.GetParameters())
      {
         outputBlock.Text += String.Format("Attributes for parameter {0}, \"{1}\": {2} ({3})",  
            param.Position, param.Name, param.Attributes, (int)param.Attributes);

         if (param.ParameterType.IsByRef)
         {
            outputBlock.Text += "; the parameter type is ref\n";
         }
         else
         {
            outputBlock.Text += "\n";
         }
      }
   }
}

/* This code produces the following output:

MethodInfo.ToString(): Void mymethod(System.String, System.String ByRef, System.String ByRef)
Attributes for parameter 0, "str1": None (0)
Attributes for parameter 1, "str2": None (0); the parameter type is ByRef
Attributes for parameter 2, "str3": Out (2); the parameter type is ByRef
Attributes for parameter 3, "str4": In (1)
 */


Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

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