Private Sub DemonstrateRowBeginEdit()
     Dim table As New DataTable("table1")
     Dim column As New DataColumn("col1", Type.GetType("System.Int32"))
     AddHandler table.RowChanged, AddressOf Row_Changed
     table.Columns.Add(column)

     ' Add a UniqueConstraint to the table.
     table.Constraints.Add(New UniqueConstraint(column))

     ' Add five rows.
     Dim newRow As DataRow

     Dim i As Integer
     For i = 0 To 4
         ' RowChanged event will occur for every addition.
         newRow = table.NewRow()
         newRow(0) = i
         table.Rows.Add(newRow)
     Next i

     ' AcceptChanges.
     table.AcceptChanges()

     ' Invoke BeginEdit on each.
     Console.WriteLine(ControlChars.Cr _
        & " Begin Edit and print original and proposed values " _
        & ControlChars.Cr)
     Dim row As DataRow
     For Each row In  table.Rows           
         row.BeginEdit()
         row(0) = CInt(row(0)) & 10
         Console.Write(ControlChars.Tab & " Original " & ControlChars.Tab _
            & row(0, DataRowVersion.Original).ToString())
         Console.Write(ControlChars.Tab & " Proposed " & ControlChars.Tab _
            & row(0, DataRowVersion.Proposed).ToString() & ControlChars.Cr)
     Next row
     Console.WriteLine(ControlChars.Cr)

     ' Accept changes
     table.AcceptChanges()

     ' Change two rows to identical values after invoking BeginEdit.
     table.Rows(0).BeginEdit()
     table.Rows(1).BeginEdit()
     table.Rows(0)(0) = 100
     table.Rows(1)(0) = 100
     Try
         ' Now invoke EndEdit. This will cause the UniqueConstraint
         ' to be enforced.
         table.Rows(0).EndEdit()
         table.Rows(1).EndEdit()
     Catch e As Exception
     ' Process exception and return.
         Console.WriteLine("Exception of type {0} occurred.", _
            e.GetType().ToString())
     End Try
 End Sub

 Private Sub Row_Changed _
 (sender As Object, e As System.Data.DataRowChangeEventArgs)
     Dim table As DataTable = CType(sender, DataTable)
     Console.WriteLine("RowChanged " & e.Action.ToString() _
        & ControlChars.Tab & e.Row.ItemArray(0).ToString())
 End Sub

private void DemonstrateRowBeginEdit()
{
    DataTable table = new DataTable("table1");
    DataColumn column = new 
        DataColumn("col1",Type.GetType("System.Int32"));
    table.RowChanged+=new 
        DataRowChangeEventHandler(Row_Changed);
    table.Columns.Add(column);

    // Add a UniqueConstraint to the table.
    table.Constraints.Add(new UniqueConstraint(column));

    // Add five rows.
    DataRow newRow;

    for(int i = 0;i<5; i++)
    {
        // RowChanged event will occur for every addition.
        newRow= table.NewRow();
        newRow[0]= i;
        table.Rows.Add(newRow);
    }
    // AcceptChanges.
    table.AcceptChanges();

    // Invoke BeginEdit on each.
    Console.WriteLine(
        "\n Begin Edit and print original and proposed values \n");
    foreach(DataRow row in table.Rows)
    {

        row.BeginEdit();
        row[0]=(int) row[0]+10;
        Console.Write("\table Original \table" + 
            row[0, DataRowVersion.Original]);
        Console.Write("\table Proposed \table" + 
            row[0,DataRowVersion.Proposed] + "\n");
    }
    Console.WriteLine("\n");
    // Accept changes
    table.AcceptChanges();
    // Change two rows to identical values after invoking BeginEdit.
    table.Rows[0].BeginEdit();
    table.Rows[1].BeginEdit();
    table.Rows[0][0]= 100;
    table.Rows[1][0]=100;
    try
    {
        /* Now invoke EndEdit. This will cause the UniqueConstraint
           to be enforced.*/
        table.Rows[0].EndEdit();
        table.Rows[1].EndEdit();
    }
    catch(Exception e)
    {
        // Process exception and return.
        Console.WriteLine("Exception of type {0} occurred.", 
            e.GetType());
    }
}

private void Row_Changed(object sender, 
    System.Data.DataRowChangeEventArgs e)
{
    DataTable table = (DataTable)  sender;
    Console.WriteLine("RowChanged " + e.Action.ToString() 
        + "\table" + e.Row.ItemArray[0]);
}