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DefaultEventAttribute Class

Specifies the default event for a component.

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

[AttributeUsageAttribute(AttributeTargets.Class)]
public sealed class DefaultEventAttribute : Attribute

Use the Name property to get the name of the default event.

For more information, see Attributes Overview and Extending Metadata Using Attributes.

The following example defines a collection class named MyCollection. The class is marked with a DefaultEventAttribute that specifies CollectionChanged as the default event.

[DefaultEvent("CollectionChanged")]
public class MyCollection : BaseCollection {

    private CollectionChangeEventHandler onCollectionChanged;

    public event CollectionChangeEventHandler CollectionChanged {
       add {
          onCollectionChanged += value;
       }
       remove {
          onCollectionChanged -= value;
       }
    }
    // Insert additional code.
}

The next example creates an instance of MyCollection. Then it gets the attributes for the class, extracts the DefaultEventAttribute, and prints the name of the default event.

public static int Main() {
    // Creates a new collection.
    MyCollection myNewCollection = new MyCollection();

    // Gets the attributes for the collection.
    AttributeCollection attributes = TypeDescriptor.GetAttributes(myNewCollection);

    /* Prints the name of the default event by retrieving the 
     * DefaultEventAttribute from the AttributeCollection. */
    DefaultEventAttribute myAttribute = 
       (DefaultEventAttribute)attributes[typeof(DefaultEventAttribute)];
    Console.WriteLine("The default event is: " + myAttribute.Name);
    return 0;
 }

System.Object
  System.Attribute
    System.ComponentModel.DefaultEventAttribute

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98

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

.NET Framework

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

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