Working with DataTable Events 

The DataTable object provides a series of events that can be processed by an application. The following table describes DataTable events.

Event	Description
ColumnChanged	Occurs when a value has been inserted successfully into a column.
ColumnChanging	Occurs when a value has been submitted for a column.
RowChanged	Occurs after a row in the table has been edited successfully.
RowChanging	Occurs when a row in the table is changing.
RowDeleted	Occurs after a row in the table has been marked as Deleted.
RowDeleting	Occurs before a row in the table is marked as Deleted.

The following example creates four events: OnColumnChanged, OnColumnChanging, OnRowChanged, and OnRowChanging. Each of these events occurs when a column or row changes.

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

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"]);
}

See Also

Reference

DataTable Class

Other Resources

Manipulating Data in a DataTable