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asp.netdrop-down-menuautopostback

Dropdownlist looses value during autopostback

I have a couple of straightforward dropdownlists. The first is bound by a linqdatsource in the html with autopostback set to true. The selection of the first determines the data in the second. When I select an item in the first, the selectedindexChanged event fires; however, the selected value is always the first item in the list and the list then re-binds and reverts to its default state. Do I have to bind it in code-behind to prevent this? 

<asp:DropDownList ID="dd_shirtcolor" runat="server" AppendDataBoundItems="true" AutoPostBack="True">
    <asp:ListItem Text="Select Color" />
</asp:DropDownList>

<asp:LinqDataSource ID="LinqDataSource1" runat="server"
    ContextTypeName="IPC.IPCDataDataContext" EntityTypeName=""
    TableName="Shirts" Where="IsActive == @IsActive">
    <WhereParameters>
        <asp:Parameter DefaultValue="true" Name="IsActive" Type="Boolean" />
    </WhereParameters>
</asp:LinqDataSource>
Solution

  • Some alternatives to managing cascading drop down lists yourself are:

    ASP.NET AJAX Control Toolkit: ASP.NET AJAX Cascading Drop Down

    Cascading Drop Down Using ASP.NET and jQuery: Cascading Drop Down Using ASP.NET And jQuery