The C1GridExtender control supports moving the column at run time to change the order of columns. To allow users to resize the grid's columns at run time, simply set the AllowColMoving to True. For example, with the following markup:

<cc1:C1GridExtender runat="server" ID="GridExtender1" TargetControlID="demo" AllowColMoving="true">

At run time, drag a source column header on a target column header. Columns can be inserted either to the right or to the left of the target column, depending upon closer to which border dragged column is dropped. To add column to a band its header should be dropped to the center of band header.