IsDefined Method
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MemberInfo.IsDefined Method

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

When overridden in a derived class, indicates whether one or more attributes of the specified type or of its derived types is applied to this member.

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

public abstract bool IsDefined(
	Type attributeType,
	bool inherit


Type: System.Type
The type of custom attribute to search for. The search includes derived types.
Type: System.Boolean
true to search this member's inheritance chain to find the attributes; otherwise, false. This parameter is ignored for properties and events; see Remarks.

Return Value

Type: System.Boolean
true if one or more instances of attributeType or any of its derived types is applied to this member; otherwise, false.


ICustomAttributeProvider.IsDefined(Type, Boolean)

This method ignores the inherit parameter for properties and events. To search the inheritance chain for attributes on properties and events, use the appropriate overloads of the Attribute.IsDefined method.

The following example determines whether the specified attribute is applied to the specified member.

using System;
using System.Reflection;

// Define a custom attribute with one named parameter.
public class MyAttribute : Attribute
   private string myName;
   public MyAttribute(string name)
      myName = name;
   public string Name
         return myName;

// Define a class that has the custom attribute associated with one of its members.
public class MyClass1
   [MyAttribute("This is an example attribute.")]
   public void MyMethod(int i)

public class Example
   public static void Demo(System.Windows.Controls.TextBlock outputBlock)
         // Get the type of MyClass1.
         Type myType = typeof(MyClass1);
         // Get the members associated with MyClass1.
         MemberInfo[] myMembers = myType.GetMembers();

         // Display the attributes for each of the members of MyClass1.
         for (int i = 0; i < myMembers.Length; i++)
            // Display the attribute if it is of type MyAttribute.
            if (myMembers[i].IsDefined(typeof(MyAttribute), false))
               Object[] myAttributes = myMembers[i].GetCustomAttributes(typeof(MyAttribute), false);
               outputBlock.Text += String.Format("\nThe attributes of type MyAttribute for the member {0} are: \n",
                   myMembers[i]) + "\n";
               for (int j = 0; j < myAttributes.Length; j++)
                  // Display the value associated with the attribute.
                  outputBlock.Text += String.Format("The value of the attribute is : \"{0}\"",
                      ((MyAttribute)myAttributes[j]).Name) + "\n";
      catch (Exception e)
         outputBlock.Text += String.Format("An exception occurred: {0}", e.Message) + "\n";

Windows Phone OS

Supported in: 8.1, 8.0, 7.1, 7.0

Windows Phone

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