Use the CellSpacing property to control the spacing between adjacent cells in the GridView control. This spacing is applied both vertically and horizontally. The cell spacing is uniform for the entire control. Individual cell spacing between rows or columns cannot be specified.
If you set this property to a value greater than 0 and then set the GridLines property to a value that displays the cell borders, a gap is displayed between the borders of adjacent cells. In this situation, the CellSpacing property controls the size of the gap.
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2