Drop Down List Data Binding Issue

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:

<%@ Page Title="" Language="C#" MasterPageFile="~/Main.master" AutoEventWireup="true" CodeFile="Registrants.aspx.cs" Inherits="EventHost_Registrants" %>






USERNAME: NAME: ORGANISATION: NO. OF EVENTS:

Select Event:

Please help me out.

2 Replies

Know the answer? Post it — somebody with the same question will find it here.

Gagan Sikri12y ago
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.
0
Arunava Bhattacharjee12y ago
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)
0