On the C# side, I've created an datatable that will read a multi-dimensional array. Each row has a boolean value at the moment that suggests whether it should be highlighted or not.

What I don't know how to do is to have duplicate rows automatically hightlighted on the datagrid.

Can anyone help?

Try putting a flag in the resultset(for the grid) that indicates whether or not to hightlight the row. You can set the visible property to false for that column in the grid(in the page_load event). Then in the RowDataBound event of the grid, check the value, and set the bgcolor of the row accordingly.

Jim