int nowCount = 0;

if (gro.dataViewMain.Table.Rows.Count < 1 || gro.dataViewMain.Table.Compute("Max(no)", null) == null)
nowCount = 1;
else
nowCount = Convert.ToInt32(gro.dataViewMain.Table.Compute("Max(no)", null)) + 1;
DataRowView dtRow = null;
dtRow = gro.dataViewMain.AddNew();
dtRow.BeginEdit();
dtRow["no"] = nowCount;
dtRow["ClosingDate"] = ComKikan.Text;



dtRow.EndEdit();