C#时间

                DateTime tmEndDate = DateTime.Today;

                DateTime tmBuyDate;
                CommandText = "select .... from ..... where id=" + tbid.ToString();
                tmBuyDate = Convert.ToDateTime(sqlAccess.ExecuteScalar(CommandText));

                int iMonthCount = ((tmEndDate.Year) - (tmBuyDate.Year)) * 12;
                iMonthCount += (tmEndDate.Month) - (tmBuyDate.Month);
                if ((tmEndDate.Day) - (tmBuyDate.Day) < 0)
                {
                    iMonthCount--;
                }
				
				
				 protected void gridSystemList_RowCreated(object sender, GridViewRowEventArgs e)
        {
            if (e.Row.RowIndex > -1)
            {
                if (dtSystemDetail != null && dtSystemDetail.Rows.Count > 0)
                {
                    string dtSystemDetail = Convert.ToString(dtSystemDetail.Rows[e.Row.RowIndex].ItemArray[dtSystemDetail.Columns.IndexOf("dtSystemDetail")]);
                    string  StartTime = Convert.ToString(dtSystemDetail.Rows[e.Row.RowIndex].ItemArray[dtSystemDetail.Columns.IndexOf("StartTime")]);
                    string EndTime = Convert.ToString(dtSystemDetail.Rows[e.Row.RowIndex].ItemArray[dtSystemDetail.Columns.IndexOf("EndTime")]);
                    int Question = Convert.ToInt32(dtSystemDetail.Rows[e.Row.RowIndex].ItemArray[dtSystemDetail.Columns.IndexOf("Question")]);
                    DateTime nowaday = DateTime.Today;
                    DateTime StartTime = DateTime.Today;
                    DateTime EndTime = DateTime.Today;
                    if (StartTime.Length > 0)
                        StartTime = Convert.ToDateTime(StartTime);
                    if (EndTime.Length>0)
                        EndTime = Convert.ToDateTime(EndTime);
                    if (StartTime.Length<=0 && EndTime.Length<=0)
                        e.Row.Cells[12].Enabled = false;
                    if (StartTime.Length > 0 && EndTime.Length > 0 && Question>0) {

                        if (nowaday.Day-StartTime.Day>=0 && EndTime.Day- nowaday.Day>=0) {
                            ((Label)e.Row.Cells[10].FindControl("lbldtSystemDetail")).Text = dtSystemDetail;
                        } else {
                            if (dtSystemDetail.Length>0) {
                                ((Label)e.Row.Cells[10].FindControl("lbldtSystemDetail")).Text = dtSystemDetail;
                            }
                            else
                            {
                                ((Label)e.Row.Cells[10].FindControl("lbldtSystemDetail")).Text = "未在答疑时间。";
                            }
                            e.Row.Cells[12].Enabled = false;
                        }
                    }
                }
            }
        }