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

Definizione

Viene generato quando l'insieme delle colonne viene modificato mediante l'aggiunta o la rimozione di una colonna.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 

Esempi

Nell'esempio seguente viene aggiunto un gestore eventi per l'evento 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

Commenti

Usare i Contains metodi CanRemove e per determinare se una colonna esiste e può essere rimossa.Use the Contains and CanRemove methods to determine whether a column exists and can be removed.

Si applica a