private void dataGridView1_CellMouseUp(object sender, DataGridViewCellMouseEventArgs e)
{
         if (e.RowIndex != -1)
         {
                  DataGridViewRow currentRow = dataGridView1.CurrentRow;

                  txtCatID.Text = (currentRow.Cells[0].Value != null) ? currentRow.Cells[0].Value.ToString() : string.Empty;
                  txtCatName.Text = (currentRow.Cells[1].Value != null) ? currentRow.Cells[1].Value.ToString() : string.Empty;
                  txtDes.Text = (currentRow.Cells[2].Value != null) ? currentRow.Cells[2].Value.ToString() : string.Empty;
         }
}