如何在c#中对数据表应用过滤器？它给出错误

如何解决如何在c#中对数据表应用过滤器？它给出错误

public void btn_abnrmalsixnine_Click(object sender,EventArgs e)
{
        try
        {

            DataTable dt_temp = new DataTable();
            DataSet ds = (DataSet)ViewState["GridViewData"];
            //DataTable DT_Main = (DataTable)ViewState["GridViewData"];
            DataTable DT_Main = ds.Tables[0];
            dt_temp = DT_Main.Clone();
            //Button btnEdit = (Button)sender;
            //ASPxGridView Grow = (ASPxGridView)btnEdit.NamingContainer; 
            // Session["AttendanceDate"] = Grow.RowIn
            for (int i = 0; i < grv_NormalabnormalSummaryReport.VisibleRowCount; i++)
            {
                Session["AttendanceDate"] = (this.grv_NormalabnormalSummaryReport.GetRowValues(i,"AttendanceDate").ToString());
                string AttendanceDate = Session["AttendanceDate"].ToString();
                //  ASPxGridView row = (ASPxGridView)grv_NormalabnormalSummaryReport.GetSelectedFieldValues();
                dt_temp = DT_Main.AsEnumerable().Where(r => r.Field<DateTime>("AttendanceDate").ToString() == AttendanceDate
                                                     && r.Field<string>("AttendanceStatus").ToString() == "Abnormal" &&
                                                        r.Field<int>("TravelTime") >= 6 &&
                                                        r.Field<int>("TravelTime") <= 9).CopyToDataTable();

                grv_EmployeeList.DataSource = dt_temp;
                grv_EmployeeList.DataBind();
                popupEmployeeList.ShowOnPageLoad = true;
        }

它给出异常'源不包含数据行'

解决方法

不要在 CopyToDataTable() 之后使用 Where。只需存储在 query 中，然后为 query.Count() > 0 添加条件，如果它有任何记录，则返回 true，然后仅使用 CopyToDataTable()。

试试下面的完整代码。

var query = DT_Main.AsEnumerable().Where(r => r.Field<DateTime>("AttendanceDate").ToString() == AttendanceDate && 
                                            r.Field<string>("AttendanceStatus").ToString() == "Abnormal" &&
                                            r.Field<int>("TravelTime") >= 6 &&
                                            r.Field<int>("TravelTime") <= 9);
if (query.Count() > 0)
{
    dt_temp = query.CopyToDataTable();
}