Private Shared Sub DataTableColumnChanging()
    Dim custTable As DataTable = New DataTable("Customers")
    ' add columns
    custTable.Columns.Add("id", Type.GetType("System.Int32"))
    custTable.Columns.Add("name", Type.GetType("System.String"))
    custTable.Columns.Add("address", Type.GetType("System.String"))

    ' set PrimaryKey
    custTable.Columns("id").Unique = true
    custTable.PrimaryKey = New DataColumn() { custTable.Columns("id") }

    ' add a ColumnChanging event handler for the table.
    AddHandler custTable.ColumnChanging, New _
        DataColumnChangeEventHandler(AddressOf Column_Changing )

    ' add ten rows
    Dim id As Integer
    For id = 1 To 10
        custTable.Rows.Add( _
            New Object() { id, string.Format("customer{0}", id), _
                string.Format("address{0}", id) })
    Next
    
    custTable.AcceptChanges()

    ' change the name column in all the rows
    Dim row As DataRow
    For Each row In custTable.Rows 
        row("name") = string.Format("vip{0}", row("id"))
    Next

End Sub

Private Shared Sub Column_Changing(sender As Object, _
    e As DataColumnChangeEventArgs)
    Console.WriteLine( _
        "Column_Changing Event: name={0}; Column={1}; proposed name={2}", _
        e.Row("name"), e.Column.ColumnName, e.ProposedValue) 
End Sub

    private static void DataTableColumnChanging()
    {
        DataTable custTable = new DataTable("Customers");
        // add columns
        custTable.Columns.Add("id", typeof(int));
        custTable.Columns.Add("name", typeof(string));
        custTable.Columns.Add("address", typeof(string));

        // set PrimaryKey
        custTable.Columns[ "id" ].Unique = true;
        custTable.PrimaryKey = new DataColumn[] { custTable.Columns["id"] };

        // add a ColumnChanging event handler for the table.
        custTable.ColumnChanging += new 
            DataColumnChangeEventHandler(Column_Changing );


        // add ten rows
        for(int id=1; id<=10; id++)
        {
            custTable.Rows.Add(
                new object[] { id, string.Format(
                "customer{0}", id), string.Format("address{0}", id) });
        }
    
        custTable.AcceptChanges();

        // change the name column in all the rows
        foreach(DataRow row in custTable.Rows )
        {
            row["name"] = string.Format("vip{0}", row["id"]);
        }

    }

    private static void Column_Changing(object sender, 
        DataColumnChangeEventArgs e )
    {
        Console.WriteLine(
            "Column_Changing Event: name={0}; Column={1}; proposed name={2}", 
            e.Row["name"], e.Column.ColumnName, e.ProposedValue );
    }