if (e.KeyCode == Keys.Down)
         {
             int c = userControl11.CurrentCell.ColumnIndex;
             int r = userControl11.CurrentCell.RowIndex;
             if (r < userControl11.Rows.Count - 1) //check for index out of range
                 userControl11.CurrentCell = userControl11[c, r + 1];
         }
         if (e.KeyCode == Keys.Up)
         {
             int c = userControl11.CurrentCell.ColumnIndex;
             int r = userControl11.CurrentCell.RowIndex;
             if (r > 0) //userControl11 for index out of range
                 userControl11.CurrentCell = userControl11[c, r - 1];
         }
         if (e.KeyCode == Keys.Back || e.KeyCode == Keys.Left)
         {
             //to check if you are in first cell of any line 
             if (iColumn == 0)
             {
                 //to check if you are in first cell of fist line 
                 if (iRow == 0)
                 {
                     MessageBox.Show("you reached first cell");
                 }
                 else
                 {
                     userControl11.CurrentCell = userControl11[userControl11.ColumnCount - 1, iRow - 1];
                 }
             }
             else
             {
                 userControl11.CurrentCell = userControl11[iColumn - 1, iRow];
             }
         }