DataColumnCollection.CollectionChanged 事件

定義

命名空間:
System.Data
組件:
System.Data.dll, netstandard.dll, System.Data.Common.dll

發生於資料行集合變更時 (藉由加入或移除資料行)。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

範例

下列範例會加入 CollectionChanged 事件的事件處理常式。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

備註

使用 Contains 和 CanRemove 方法來判斷資料行是否存在，以及是否可以移除。Use the Contains and CanRemove methods to determine whether a column exists and can be removed.

適用於