System.Data Namespace   DataColumnCollection Class

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Occurs when the columns collection changes, either by adding or removing a column.

[ VB ]
Public Event CollectionChanged As CollectionChangeEventHandler

[ C# ]
public event CollectionChangeEventHandler CollectionChanged;

[ C++ ]
public: __event CollectionChangeEventHandler* CollectionChanged;

[ JScript ] In JScript, you can handle the events defined by a class, but you cannot define your own.

The event handler receives a CollectionChangeEventArgs containing data related to the CollectionChanged event. The following CollectionChangeEventArgs properties provide information specific to this event.

Property	Description
Action	Gets an action that specifies how the collection changed.
Element	Gets the instance of the collection with the change.

The Contains and CanRemove methods can be used to determine if a column exists and can be removed.

The following example adds an event handler for the CollectionChanged event.

private void AddHandler ( DataTable myTable ) {
   DataColumnCollection cols=myTable.Columns;
   cols.CollectionChanged += 
      new System.ComponentModel.CollectionChangeEventHandler (
      DataColumnCollection_Changed );
}
          
private void DataColumnCollection_Changed ( object sender,
   System.ComponentModel.CollectionChangeEventArgs e ) {
   DataColumnCollection cols= ( DataColumnCollection ) sender;
   Response.Write ( "DataColumnCollectionChanged: " + cols.Count );
}

DataColumnCollection Members

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