Export (0) Print
Expand All

DefaultEventAttribute Class

Specifies the default event for a component.

System.Object
  System.Attribute
    System.ComponentModel.DefaultEventAttribute

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

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

The DefaultEventAttribute type exposes the following members.

  NameDescription
Public methodDefaultEventAttributeInitializes a new instance of the DefaultEventAttribute class.
Top

  NameDescription
Public propertyNameGets the name of the default event for the component this attribute is bound to.
Public propertyTypeIdWhen implemented in a derived class, gets a unique identifier for this Attribute. (Inherited from Attribute.)
Top

  NameDescription
Public methodEqualsReturns whether the value of the given object is equal to the current DefaultEventAttribute. (Overrides Attribute.Equals(Object).)
Public methodGetHashCodeReturns the hash code for this instance. (Overrides Attribute.GetHashCode().)
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodIsDefaultAttributeWhen overridden in a derived class, indicates whether the value of this instance is the default value for the derived class. (Inherited from Attribute.)
Public methodMatchWhen overridden in a derived class, returns a value that indicates whether this instance equals a specified object. (Inherited from Attribute.)
Public methodToStringReturns a string that represents the current object. (Inherited from Object.)
Top

  NameDescription
Public fieldStatic memberDefaultSpecifies the default value for the DefaultEventAttribute, which is null. This static field is read-only.
Top

  NameDescription
Explicit interface implemetationPrivate method_Attribute.GetIDsOfNamesMaps a set of names to a corresponding set of dispatch identifiers. (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.GetTypeInfoRetrieves the type information for an object, which can be used to get the type information for an interface. (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.GetTypeInfoCountRetrieves the number of type information interfaces that an object provides (either 0 or 1). (Inherited from Attribute.)
Explicit interface implemetationPrivate method_Attribute.InvokeProvides access to properties and methods exposed by an object. (Inherited from Attribute.)
Top

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

For more information, see 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;
 }

.NET Framework

Supported in: 4.5.3, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

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.

Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.
Show:
© 2014 Microsoft