How do I add an unbound checkbox column to my ASP.NET GridView?

.NET v3.5

I have what seems to be some simple code that I've gotten to work before:

TableCell cell = new TableCell();
CheckBox c = new CheckBox();
c.AutoPostBack = true;
c.ID = string.Format( "cb_{0}", row.RowIndex ); // "row" is a GridViewRow
cell.Controls.Add( c );
row.Cells.AddAt( 0, cell );

The problem is the checkboxes aren't persisted between postbacks. But if I simply call the method on every postback, it prepends a new blank column to the front of the grid every time which pushes the data in the rows to the right for every postback. It's weird; each row will have the same number of cells and not change. It's just that the data gets "shifted" to the right. So data that was in cell[1] will appear 开发者_JS百科in cell[2] after a postback. Then in cell[3] after the next postback. Etc.

What's up with this? Please remember this data is unbounded. The grid itself is not templatized but is being created on the fly from code. I simply need a way to check rows selected by the user.

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Are you posting back when the user checks the box? Are you creating this grid everytime you write the page? Why not check first if the column in position 0 is already of a checkbox type?

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I think you need to put the code that add a new column to the grid on the page init.