private void btnDeleteJoin_Click(object sender, EventArgs e)
{
int rowIndex = -1;
if (grdJoin.SelectedRows.Count == 1)
rowIndex = grdJoin.SelectedRows[0].Index;
else if (grdJoin.SelectedCells.Count == 1)
rowIndex = grdJoin.SelectedCells[0].RowIndex;
if (rowIndex >= 0)
grdJoin.Rows.RemoveAt(rowIndex);
}