DataColumnCollection.CollectionChanged 事件

定义

在由于添加或删除列而使列集合发生变化时发生。Occurs when the columns collection changes, either by adding or removing a column.

public:
 event System::ComponentModel::CollectionChangeEventHandler ^ CollectionChanged;
public event System.ComponentModel.CollectionChangeEventHandler CollectionChanged;
member this.CollectionChanged : System.ComponentModel.CollectionChangeEventHandler 
Public Custom Event CollectionChanged As CollectionChangeEventHandler 

示例

下面的示例为 CollectionChanged 事件添加事件处理程序。The following example adds an event handler for the CollectionChanged event.

   private void AddEventHandler(DataTable table)
   {
       DataColumnCollection columns = table.Columns;
       columns.CollectionChanged += new 
           System.ComponentModel.CollectionChangeEventHandler(
           ColumnsCollection_Changed);
   }

   private void ColumnsCollection_Changed(object sender, 
       System.ComponentModel.CollectionChangeEventArgs e)
   {
       DataColumnCollection columns = 
           (DataColumnCollection) sender;
       Console.WriteLine("ColumnsCollectionChanged: " 
           + columns.Count);
   }
 Private Sub AddEventHandler(table As DataTable)
     Dim columns As DataColumnCollection = table.Columns
     AddHandler columns.CollectionChanged, _
        AddressOf ColumnsCollection_Changed
 End Sub    
    
 Private Sub ColumnsCollection_Changed _
    (sender As Object, e As System.ComponentModel. _
    CollectionChangeEventArgs)

     Dim columns As DataColumnCollection = _
        CType(sender, DataColumnCollection)
     Console.WriteLine("ColumnsCollectionChanged: " _
        & columns.Count.ToString())
End Sub

注解

使用 ContainsCanRemove 方法来确定列是否存在并且是否可以删除。Use the Contains and CanRemove methods to determine whether a column exists and can be removed.

适用于