Hi all,

I'm trying to create a set of cascading DropDownLists within a BOUND FormView.

<asp:FormView ID="FormView1" ....>

<EditItemTemplate>

Program Mode:

<asp:DropDownList ID="ProgramModeID" SelectedValue='<%# Bind("ProgramModeID") %>'
    runat="server" DataSourceID="dsProgramMode" DataTextField="ProgramModeDesc" DataValueField="ProgramModeID"
    AppendDataBoundItems="true" OnSelectedIndexChanged="Program_SelectedIndexChanged"
    AutoPostBack="true">
</asp:DropDownList>
<asp:SqlDataSource ...>

Program Name:

<ajax:UpdatePanel ID="pnlProgramName" OnPreRender="FormView1_DataBinding" runat="server">
    <Triggers>
        <ajax:AsyncPostBackTrigger ControlID="ProgramCategoryID" EventName="SelectedIndexChanged" />
        <ajax:AsyncPostBackTrigger ControlID="ProgramModeID" EventName="SelectedIndexChanged" />
    </Triggers>
    <ContentTemplate>
        <asp:DropDownList ID="ProgramNameID" SelectedValue='<%# Bind("ProgramNameID") %>' runat="server" DataSourceID="dsProgramName"
            DataTextField="ProgramNameDesc" DataValueField="ProgramNameID" AppendDataBoundItems="false">
        </asp:DropDownList>
        <asp:SqlDataSource ID="dsProgramName" runat="server" ConnectionString="<%$ ConnectionStrings:SqlServer %>">
        </asp:SqlDataSource>
    </ContentTemplate>
</ajax:UpdatePanel>

Here's what I'm trying to do:

Program Name dropdownlist (DDL) should change depending on what is selected in Program Mode DDL.

The events Program_SelectedIndexChanged and FormView1_DataBinding both call this function in the codebehind:

protected void GetdsProgramName()
    {
        SqlDataSource dsProgramName = (SqlDataSource)FormView1.FindControl("dsProgramName");
        DropDownList ProgramNameID = (DropDownList)FormView1.FindControl("ProgramNameID");

        if (dsProgramName != null && ProgramNameID != null)
        {
            string SelectCommand = "SELECT ...";
            dsProgramName.SelectCommand = SelectCommand;
            ProgramNameID.DataBind();
        }
    }

 My problem is that I keep getting the error:

'ProgramNameID' has a SelectedValue which is invalid because it does not exist in the list of items.

every time I go into the FormView. I think it's because I'm not calling the GetdsProgramName function early enough and the Binding is going ahead before the ProgramNameID DDL has been bound to the list of data. If I put the same SelectCommand within the <SqlDataSource> tag, it works fine.

When should I set the SelectCommand (and databind) the DDL? On which event? I'm super confused when it comes to this Bind command of FormView, because I can never figure out when the Bind takes place.

Would greatly appreciate any help. Thanks.
 

I've got a related problem caused by the AJAX CascadedDropDownList. I don´t know why but when you do  a databinding using the "SelectedValue" property, this always get the string:  "Value_of_Item_Selected:::Name_of_item_selected".

I had to manage the event in the code behind the page before saving/modifying/inserting a record by extracting from that "strange formatted string" the real value selected. Maybe a bug?

I've got a related problem caused by the AJAX CascadedDropDownList. I don´t know why but when you do  a databinding using the "SelectedValue" property, this always get the string:  "Value_of_Item_Selected:::Name_of_item_selected".

I had to manage the event in the code behind the page before saving/modifying/inserting a record by extracting from that "strange formatted string" the real value selected. Maybe a bug?

Is this a bug? I have come across the same thing and I was going nuts. Is'nt there a solution other than manually editing the data before updating?

Please let me know if you know of any solution to this.

Thanks.