DataColumnCollection.CollectionChanged DataColumnCollection.CollectionChanged DataColumnCollection.CollectionChanged DataColumnCollection.CollectionChanged Event

Определение

Происходит, когда изменяется коллекция столбцов с помощью добавления или удаления столбца.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 

Примеры

В следующем примере добавляется обработчик событий для события CollectionChanged.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

Комментарии

Используйте методы CanRemove и, чтобы определить, существует ли столбец, и удалить его. ContainsUse the Contains and CanRemove methods to determine whether a column exists and can be removed.

Применяется к