Try this
DataControlField colIndex4 = new BoundField();<br />
colIndex4.HeaderText = "Colunm 4";<br />
grid.Columns.Add(colIndex4);<br />
<br />
DataControlField colIndex5 = new CommandField();<br />
colIndex5.HeaderText = "Colunm 5";<br />
grid.Columns.Add(colIndex5);