in the button click
TextBox textname;
TextBox textname2;
foreach (GridViewRow row in GridViewName.Rows)
{
textname= (TextBox)row.Cells[0].FindControl("TextBoxName");
textname2 = (TextBox)row.Cells[1].FindControl("TextBoxName");
}
(TextBox)row.Cells[0]
type the number of the cell here as you make it in the grid .