CollectionChangeEventArgs Class
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CollectionChangeEventArgs Class


Provides data for the CollectionChanged event.

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


[HostProtectionAttribute(SecurityAction.LinkDemand, SharedState = true)]
public class CollectionChangeEventArgs : EventArgs

System_CAPS_pubmethodCollectionChangeEventArgs(CollectionChangeAction, Object)

Initializes a new instance of the CollectionChangeEventArgs class.


Gets an action that specifies how the collection changed.


Gets the instance of the collection with the change.


Determines whether the specified object is equal to the current object.(Inherited from Object.)


Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection.(Inherited from Object.)


Serves as the default hash function. (Inherited from Object.)


Gets the Type of the current instance.(Inherited from Object.)


Creates a shallow copy of the current Object.(Inherited from Object.)


Returns a string that represents the current object.(Inherited from Object.)

A CollectionChanged event is raised when you change which items are in a collection, for example, by adding an element to a collection or removing an element from the collection. This event is not raised when an individual element changes its value.

The following code example demonstrates the use of this type. In the example, an event handler reports on the occurrence of the AutoCompleteStringCollection.CollectionChanged event. This report helps you to learn when the event occurs and can assist you in debugging. To report on multiple events or on events that occur frequently, consider replacing MessageBox.Show with Console.WriteLine or appending the message to a multiline TextBox.

To run the example code, paste it into a project that contains an instance of type AutoCompleteStringCollection named AutoCompleteStringCollection1. Then ensure that the event handler is associated with the AutoCompleteStringCollection.CollectionChanged event.

private void AutoCompleteStringCollection1_CollectionChanged(Object sender, CollectionChangeEventArgs e) {

System.Text.StringBuilder messageBoxCS = new System.Text.StringBuilder();
messageBoxCS.AppendFormat("{0} = {1}", "Action", e.Action );
messageBoxCS.AppendFormat("{0} = {1}", "Element", e.Element );
MessageBox.Show(messageBoxCS.ToString(), "CollectionChanged Event" );

.NET Framework
Available since 1.1

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

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