Grid Inside gridview's row show empty text

Hi all,
 if (gvParentGrid.Rows.Count > 0)
                {

                    for (int i = 0; i < gvParentGrid.Rows.Count; i++)
                    {
                        string projectname = gvParentGrid.Rows[i].Cells[1].Text;

                        GridView gvchild = (GridView)gvParentGrid.Rows[i].FindControl("gvChildGrid");



             & ...