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Attribute.IsDefined Method (ParameterInfo, Type)

 

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

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

public static bool IsDefined(
	ParameterInfo element,
	Type attributeType
)

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.

Return Value

Type: System.Boolean

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

Exception Condition
ArgumentNullException

element or attributeType is null.

ArgumentException

attributeType is not derived from Attribute.

The ancestors of element are searched for custom attributes.

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
Available since 1.1
Portable Class Library
Supported in: portable .NET platforms
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
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