protected void ddl_ExamDate_SelectedIndexChanged(object sender, EventArgs e)
        {
            if (ddl_ExamDate.SelectedValue?.ToString() != "-1")
            {
                BindDrpExamSaatsByExamDate(ddl_ExamDate.SelectedValue);
                RefreshGrid(null, ddl_Cities.SelectedValue, -1, ddl_ExamDate.SelectedValue, ddl_Saat.SelectedValue);
            }
            else
            {
                ddl_Saat.DataSource = new DataTable();
                ddl_Saat.DataBind();

                RadG_AllDids.DataSource = new DataTable();
                RadG_AllDids.DataBind();
            }
        }
        void RefreshGrid(string term = null, string examPlaceID = "-1", int did = -1, string examDate = "-1", string examTime = "-1")
        {
            if (string.IsNullOrEmpty(ddl_Cities.SelectedValue) || ddl_Cities.SelectedValue?.ToString() == "-2")
            {
                ddl_ExamDate.SelectedValue = "-1";
                ddl_Saat.SelectedValue     = "-1";

                RadG_AllDids.DataSource = new DataTable();
                RadG_AllDids.DataBind();
            }
            else
            {
                DataTable dt       = new DataTable();
                var       dateexam = (string.IsNullOrEmpty(ddl_ExamDate.SelectedValue) || ddl_ExamDate.SelectedValue == "-1") ? "-1" : ddl_ExamDate.SelectedValue;
                var       saatexam = (string.IsNullOrEmpty(ddl_Saat.SelectedValue) || ddl_Saat.SelectedValue == "-1") ? "-1" : ddl_Saat.SelectedValue;

                dt = EBusiness.GetAllDidsByInputFilters(term, int.Parse(examPlaceID), did, examDate, examTime);

                RadG_AllDids.DataSource = dt;
                RadG_AllDids.DataBind();
            }
        }