Trouble binding C# list to DropDownList in ASP.net
Question
I've been banging my head against the wall for the past hour or so because I can't figure out what I'm doing wrong in this seemingly straight-forward process.
Here is what the ASPX page looks like:
<%@ Page Title="Teams" Language="C#" AutoEventWireup="true" CodeBehind="TeamEntry.aspx.cs" Inherits="Team.Model" Runat="server" Debug="true"%>
<!DOCTYPE html>
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
</head>
<body>
<form id="form1" runat="server">
<div>
</div>
<asp:DropDownList
runat="server"
ID="DDL_Teams"
Width="183px">
</asp:DropDownList>
<input id="Text1" type="text" /><input id="Submit1" type="submit" value="submit" />
</form>
</body>
</html>
and here is the code behind:
using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Diagnostics;
using Team;
namespace Team
{
public partial class TeamEntry : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
using (var DDL_Teams = new DropDownList())
{
DDL_Teams.DataSource = TeamsList;
DDL_Teams.DataBind();
}
}
}
List<string> TeamsList = new List<string>()
{
"Alpha", "Bravo", "Charlie", "Delta"
};
}
}
...but all I see when I try to run the page is an empty dropdown list
I've tried several other approaches noted in other StackOverflow questions related to data binding to dropdown lists (for example, the ones listed on this page ) to no avail. Any help would be much appreciated.
2 answers
solution1
0 2020-08-13 23:48:11
You are creating a new dropdown list every time as per this code
using (var DDL_Teams = new DropDownList())
That's why no binding has occured.
But need to use the dropdown list ID created in HTML. Please use this code in TeamEntry.aspx.cs
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
DDL_Teams.DataSource = TeamsList;
DDL_Teams.DataBind();
}
}
List<string> TeamsList = new List<string>()
{
"Alpha", "Bravo", "Charlie", "Delta"
};
solution2
0 2020-08-14 01:38:07
Remove your Dropdownlist on your server side code:
if (!IsPostBack)
{
//using (var DDL_Teams = new DropDownList()) - Comment this line
{
DDL_Teams.DataSource = TeamsList;
DDL_Teams.DataBind();
}
}
You already have DDL_Teams on your web form already. Try to clean your solution and rebuild it.
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