DataColumnCollection.CollectionChanged 事件

定義

命名空間:

System.Data

組件:

System.Data.Common.dll

來源:

DataColumnCollection.cs

發生於資料行集合變更時 (藉由加入或移除資料行)。

public:
 event System::ComponentModel::CollectionChangeEventHandler ^ CollectionChanged;

public event System.ComponentModel.CollectionChangeEventHandler? CollectionChanged;

member this.CollectionChanged : System.ComponentModel.CollectionChangeEventHandler 

Public Custom Event CollectionChanged As CollectionChangeEventHandler 

事件類型

CollectionChangeEventHandler

範例

下列範例會新增 CollectionChanged 事件的事件處理常式。

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

Contains使用 和 CanRemove 方法來判斷資料行是否存在且可移除。