Trabajar con eventos DataTable
El objeto DataTable proporciona una serie de eventos que una aplicación puede procesar. En la siguiente tabla se describen los eventos de DataTable.
| Evento | Descripción |
|---|---|
| ColumnChanged | Se produce cuando se inserta correctamente un valor en una columna. |
| ColumnChanged | Se produce cuando se envía un valor para una columna. |
| RowChanged | Se produce después de editar correctamente una fila de la tabla. |
| RowChanging | Se produce mientras está cambiando una fila de la tabla. |
| RowDeleted | Se produce después de que se haya marcado como Deleted una fila de la tabla. |
| RowDeleting | Se produce antes de que se haya marcado como Deleted una fila de la tabla. |
En el ejemplo siguiente se crean cuatro eventos: OnColumnChanged, OnColumnChanging, OnRowChanged y OnRowChanging. Cada uno de los eventos se produce cuando cambia una columna o una fila.
AddHandler workTable.ColumnChanged, New DataColumnChangeEventHandler(AddressOf OnColumnChanged)
AddHandler workTable.ColumnChanging, New DataColumnChangeEventHandler(AddressOf OnColumnChanging)
AddHandler workTable.RowChanged, New DataRowChangeEventHandler(AddressOf OnRowChanged)
AddHandler workTable.RowChanging, New DataRowChangeEventHandler(AddressOf OnRowChanging)
Private Shared Sub OnColumnChanged(sender As Object, args As DataColumnChangeEventargs)
Console.Write(" ColumnChanged: ")
Console.Write(args.Column.ColumnName & " changed to '" & args.ProposedValue.ToString() & "'" & vbCrLf)
End Sub
Private Shared Sub OnColumnChanging(sender As Object, args As DataColumnChangeEventargs)
Console.Write("ColumnChanging: ")
Console.Write(args.Column.ColumnName & " equals '" & args.Row(args.Column).ToString() & _
"', changing to '" & args.ProposedValue.ToString() & "'" & vbCrLf)
End Sub
Private Shared Sub OnRowChanging(sender As Object, args As DataRowChangeEventargs)
If args.Action <> DataRowAction.Nothing Then
Dim actionStr As String
actionStr = System.Enum.GetName(args.Action.GetType(), args.Action)
Console.WriteLine(" RowChanging: Action = " & actionStr & ", CustID = " & args.Row("CustID").ToString())
End If
End Sub
Private Shared Sub OnRowChanged(sender As Object, args As DataRowChangeEventargs)
If args.Action <> DataRowAction.Nothing Then
Dim actionStr As String
actionStr = System.Enum.GetName(args.Action.GetType(), args.Action)
Console.WriteLine(" RowChanged: Action = " & actionStr & ", CustID = " & args.Row("CustID").ToString())
End If
End Sub
[C#]
workTable.ColumnChanged += new DataColumnChangeEventHandler(OnColumnChanged);
workTable.ColumnChanging += new DataColumnChangeEventHandler(OnColumnChanging);
workTable.RowChanged += new DataRowChangeEventHandler(OnRowChanged);
workTable.RowChanging += new DataRowChangeEventHandler(OnRowChanging);
protected static void OnColumnChanged(object sender, DataColumnChangeEventArgs args)
{
Console.Write(" ColumnChanged: ");
Console.Write(args.Column.ColumnName + " changed to '" + args.ProposedValue + "'\n");
}
protected static void OnColumnChanging(object sender, DataColumnChangeEventArgs args)
{
Console.Write("ColumnChanging: ");
Console.Write(args.Column.ColumnName + " equals '" + args.Row[args.Column] +
"', changing to '" + args.ProposedValue + "'\n");
}
protected static void OnRowChanging(object sender, DataRowChangeEventArgs args)
{
if (args.Action != DataRowAction.Nothing)
Console.WriteLine(" RowChanging: Action = " + args.Action + ", CustID = " + args.Row["CustID"]);
}
protected static void OnRowChanged(object sender, DataRowChangeEventArgs args)
{
if (args.Action != DataRowAction.Nothing)
Console.WriteLine(" RowChanged: Action = " + args.Action + ", CustID = " + args.Row["CustID"]);
}