Private Shared Sub DataTableColumnChanging()
    Dim custTable As 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