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Attribute.IsDefined Method (ParameterInfo, Type, Boolean)

Determines whether any custom attributes are applied to a method parameter. Parameters specify the method parameter, the type of the custom attribute to search for, and whether to search ancestors of the method parameter.

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

public static bool IsDefined(
	ParameterInfo element,
	Type attributeType,
	bool inherit
)

Parameters

element
Type: System.Reflection.ParameterInfo

An object derived from the ParameterInfo class that describes a parameter of a member of a class.

attributeType
Type: System.Type

The type, or a base type, of the custom attribute to search for.

inherit
Type: System.Boolean

If true, specifies to also search the ancestors of element for custom attributes.

Return Value

Type: System.Boolean
true if a custom attribute of type attributeType is applied to element; otherwise, false.

ExceptionCondition
ArgumentNullException

element or attributeType is null.

ArgumentException

attributeType is not derived from Attribute.

ExecutionEngineException

element is not a method, constructor, or type.

The following code example illustrates the use of IsDefined, taking a ParameterInfo as a parameter.

using System;
using System.Reflection;

namespace IsDef5CS 
{
    public class TestClass 
    {
        // Assign a ParamArray attribute to the parameter using the keyword. 
        public void Method1(params String[] args)
        {}
    }

    public class DemoClass 
    {
        static void Main(string[] args) 
        {
            // Get the class type to access its metadata.
            Type clsType = typeof(TestClass);
            // Get the MethodInfo object for Method1.
            MethodInfo mInfo = clsType.GetMethod("Method1");
            // Get the ParameterInfo array for the method parameters.
            ParameterInfo[] pInfo = mInfo.GetParameters();
            if (pInfo != null) 
            {
                // See if the ParamArray attribute is defined. 
                bool isDef = Attribute.IsDefined(pInfo[0], 
                                                 typeof(ParamArrayAttribute));
                // Display the result.
                Console.WriteLine("The ParamArray attribute {0} defined for " +
                                  "parameter {1} of method {2}.",
                                  isDef ? "is" : "is not",
                                  pInfo[0].Name, 
                                  mInfo.Name);
            }
            else
                Console.WriteLine("The parameters information could " +
                            "not be retrieved for method {0}.", mInfo.Name);
        }
    }
}

/*
 * Output:
 * The ParamArray attribute is defined for parameter args of method Method1.
 */

.NET Framework

Supported in: 4.5, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Portable Class Library

Supported in: Portable Class Library

.NET for Windows Phone apps

Supported in: Windows Phone 8.1, Windows Phone Silverlight 8.1, Windows Phone Silverlight 8

Windows Phone 8.1, Windows Phone 8, Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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