DropDownList in FormView binding

I want to bind dropdownlist to List<MyIem>, in code behind.

 <asp:DropDownList ID="listCategories"  runat="server" Height="20px"   CssClass="CategoryDropList" SelectedValue='<%# Bind("ParentId") %>' AutoPostBack="false" Width="300px">

Without using ObjectDataSource !

How can I Bind it to the dropdown list? In what event?

Also SelectedValue='<%# Bind("ParentId") %>' should work! (I mean the dropdownlist binding should occur before this!)

Kb.

Made an example which will set the dropdown in the DataBound event.
Here is the markup
The way to use the ddl, is to find it with findcontrol() during DataBound event.
When you have the control in the DataBound event, you can also bind the dropdown to your List<>
Hope this helps.

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="Default.aspx.cs" Inherits="WebApplication1._Default" %>

    <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">

    <html xmlns="http://www.w3.org/1999/xhtml" >
    <head runat="server">
        <title>Untitled Page</title>
    </head>
    <body>
        <form id="form1" runat="server">
        <div>

        </div>
        <asp:FormView ID="FormView1" runat="server" ondatabound="FormView1_DataBound">
            <ItemTemplate>
                <asp:DropDownList ID="DropDownList1" runat="server">
                    <asp:ListItem>One</asp:ListItem>
                    <asp:ListItem>Two</asp:ListItem>
                    <asp:ListItem>Three</asp:ListItem>
                </asp:DropDownList>

            </ItemTemplate>
        </asp:FormView>
        </form>
    </body>
    </html>

Here is the code behind:

namespace WebApplication1
{
    public partial class _Default : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            List<string> list = new List<string>();
            list.Add("Some");
            list.Add("Other");

            FormView1.DataSource = list; //just to get the formview going

            FormView1.DataBind(); 

        }

        protected void FormView1_DataBound(object sender, EventArgs e)
        {
            DropDownList ddl = null;
            if(FormView1.Row != null)
                ddl = (DropDownList) FormView1.Row.FindControl("DropDownList1");
            ddl.SelectedIndex = ddl.Items.IndexOf(ddl.Items.FindByValue("Two"));
        }
    }
}

You can populate the DropDownList with another DataSource, assuming the valid values are in the database. Check out this video:

http://msdn.microsoft.com/en-us/data/cc546554.aspx

It's using an EntityDataSource instead of an ObjectDataSource, but the principle should still work.

If you want a "(none)" type option for null, see section "Converting Null in Template Fields" on this page:

http://msdn.microsoft.com/en-us/library/ms366709.aspx

Specifically:

<asp:DropDownList ID="DropDownList2" runat="server" DataSourceID="SqlDataSource2"
    DataTextField="Name" DataValueField="EmployeeID"
    SelectedValue='<%# Bind("ReportsTo") %>' AppendDataBoundItems="True">
        <asp:ListItem Selected="True" Value="">(none)</asp:ListItem>
</asp:DropDownList>

Notice the the "AppendDataBoundItems" attribute and the "asp:ListItem" element.

well i was facing a similar problem. i noticed that you were trying to add it to and not which can be a major cause that you did not see it.

i have however worked on both the solutions provided above and found this worked for me :-

<EditItemTemplate>
<asp:DropDownList ID="ddlStream" runat="server" SelectedValue='<%# Bind("Stream") %>'>
                    <asp:ListItem>Common</asp:ListItem>
                    <asp:ListItem>Mechanical</asp:ListItem>
                    <asp:ListItem>Electronics</asp:ListItem>
                    </asp:DropDownList>
</EditItemTemplate>

<ItemTemplate>
<asp:Label runat="server" id="something" text='<%# Eval("Stream")%>'/>
</ItemTemplate>

hope this helpes you.

来源：https://stackoverflow.com/questions/903869/dropdownlist-in-formview-binding

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