Drop Down List Data Binding Issue

Question

Dear Sir/Madam I am facing an issue with dropdownlist. I am binding data in dropdownlist using linq query keeping both datatextfield and datavaluefield as different attributes in table. I have set autopostback false but still when user selects a value from dropdown it does not keep value and comes back to initial value. Please help me out. CS Code: using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.UI; using System.Web.UI.WebControls; public partial class EventHost_Registrants : System.Web.UI.Page { protected void Page_Load(object sender EventArgs e) { if (Session[host] == null) { Response.Redirect(~/Error.aspx); HttpContext.Current.Response.Cache.SetCacheability(HttpCacheability.NoCache); HttpContext.Current.Response.Cache.SetNoServerCaching(); HttpContext.Current.Response.Cache.SetNoStore(); } else { Label2.Text = Session[host].ToString(); detail(); counevents(); loadevents(); GridView1.Visible = false; } } protected void ImageButton2_Click(object sender ImageClickEventArgs e) { Response.Redirect(~/EventHost/Dashboard.aspx); } protected void ImageButton3_Click(object sender ImageClickEventArgs e) { Session.RemoveAll(); Session.Abandon(); Response.Redirect(~/EventHost/AfterLogOut.aspx); } void detail() { eventmasterDataContext d = new eventmasterDataContext(); var query=from eventhost k in d.GetTable () where k.username==Label2.Text select k; Label3.Text = query.SingleOrDefault().name; Label4.Text = query.SingleOrDefault().organisation; Label7.Text = Convert.ToString(query.SingleOrDefault().hostid); } void counevents() { eventmasterDataContext count = new eventmasterDataContext(); var query2 = from eventmaster m in count.GetTable () where Convert.ToString(m.hostid) == Label7.Text select m; int result = query2.Count(); Label6.Text = Convert.ToString(result); } void loadevents() { eventmasterDataContext load = new eventmasterDataContext(); var query = from eventmaster k in load.GetTable () where k.hostid == Int32.Parse(Label7.Text) select k; DropDownList1.DataSource = query; DropDownList1.DataTextField = eventname; DropDownList1.DataValueField = eventid; DropDownList1.DataBind(); } void regns() { eventmasterDataContext reg = new eventmasterDataContext(); var query = from regnmaster k in reg.GetTable () where Convert.ToString(k.eventid)==DropDownList1.SelectedValue select k; GridView1.Visible = true; GridView1.DataSource = query; GridView1.DataBind(); } protected void ImageButton4_Click(object sender ImageClickEventArgs e) { regns(); } } Page Source: .auto-style1 { text-align: right; } .newStyle1 { font-family: Segoe UI; font-size: large; font-weight: bolder; font-style: inherit; color: #E45F56; } .auto-style2 { } .auto-style3 { text-align: right; width: 589px; } .newStyle2 { font-family: Segoe UI; font-size: large; font-weight: bolder; font-style: inherit; color: #35404F; border: thin solid #E45F56; } .newStyle3 { font-family: Segoe UI; font-size: large; } .auto-style5 { font-family: Segoe UI; font-size: large; font-weight: bolder; color: #35404F; } .auto-style6 { text-align: center; } .auto-style7 { height: 23px; }          USERNAME:          NAME:          ORGANISATION:          NO. OF EVENTS:     Select Event:           Please help me out.

Gagan Sikri · Answer

No I am still facing the same error. I select the item and when I click on display it again roles back to initial option.

Arunava Bhattacharjee · Answer

Please put .ToList() in your loadevents(). DropDownList1.DataSource=query.ToList(); Please mark the answer as accepted if it solves the problem otherwise reply what happened to the DataSource. Put a debug point. In naked eye I can see only that mistake as the LINQ query never executed. (Read about Deferred query execution you can check my article on LINQ)