Dynamically adding UserControls to an Updatepanel issue: UserControls end up with null / "broken" ObjectDataSources?

Question

So, I have an existing app where I have a sort of "main page" that contains an updatePanel. Its ContentTemplate basically loads a half-dozen different usercontrols.

I just finished adding two lines so that, basically, it will load two different instances of the same control. (But I have a special property on each line that... via a public property on the control... allows me basically to pass in a single word that helps flex the control's behavior, so it will end up displaying different data. The way I handle that is by dynamically setting that word as a Parameter on an ObjectDataSource that's defined in that usercontrol. )

        <uc:DynamicDocumentsUserControl runat="server" ID="ucDynamicDocumentsUserControl" ShowSeparatorAfterGrid="true" dynamicDocTitle="CloudSolutions" />
        <uc:DynamicDocumentsUserControl runat="server" ID="ucDynamicDocumentsUserControl1" ShowSeparatorAfterGrid="true" dynamicDocTitle="Partners"/>

Like I said, that's working.

BUT I thought it would be REALLY HANDY if, instead of hard-coding lines for these two control instances (not to mention, having to add a NEW line, every time I want to add in a new instance of the control)... I could instead put a loop in this central page's Page_Init method... and build/add the controls to that UpdatePanel dynamically.

I removed my hard-coded lines(see above) and added code to the Page_Init:

    UserControls.DynamicDocumentsUserControl ctl1 = new UserControls.DynamicDocumentsUserControl();
    ctl1.ID = "ucDynamicDocumentsUserControl";
    ctl1.DynamicDocTitle = "CloudSolutions";
    ctl1.ShowSeperatorAfterGrid = true;
    ctl1.Visible = false;

    UserControls.DynamicDocumentsUserControl ctl2 = new UserControls.DynamicDocumentsUserControl();
    ctl2.ID = "ucDynamicDocumentsUserControl1";
    ctl2.DynamicDocTitle = "Partners";
    ctl2.ShowSeperatorAfterGrid = true;
    ctl2.Visible = false;

    UserControlsUpdatePanel.ContentTemplateContainer.Controls.Add(ctl1);
    UserControlsUpdatePanel.ContentTemplateContainer.Controls.Add(ctl2);

But once that first ContentTemplateContainer.Controls.Add command fires, we go over to the Page_Init method of the "child" UserControl. And here, we try building and assigning the SelectParameter to the ObjectDataSource that's coded into the control's .ascx file.

    Parameter pm2 = new Parameter();
    pm2.Name = "documentTitle";
    pm2.DefaultValue = dynamicdoctitle;
    DynamicDocumentsDataSource.SelectParameters.Add(pm2);

And I get an error "Object reference is not set to an instance of an object. DynamicDocumentsDataSource was null."

It's as if the code-behind doesn't "see" the ?? Just for completeness-sake, here's that:

<asp:ObjectDataSource ID="DynamicDocumentsDataSource" runat="server"
    TypeName="ConnectIT.Bll.Search" SelectMethod="GetPagedDataSet"
    EnablePaging="true" SelectCountMethod="GetRowCount"
    StartRowIndexParameterName="startRow"
    MaximumRowsParameterName="pageSize" SortParameterName="sortColumns"
    OnObjectCreated="dynamicDocuments_ObjectCreated">
    <SelectParameters>
        <asp:Parameter Name="storedProc" DefaultValue="[uspGetDynamicDocuments]" />
    </SelectParameters>
</asp:ObjectDataSource>

I don't get it. Why is that part suddenly broken? It's as if the UserControl doesn't "see" this code or maybe the definition in the designer file. ???

Answer 1

I was able to get this working by loading in each of the two UserControls by file reference instead:

        UserControls.DynamicDocumentsUserControl ctl1 = LoadControl("~/UserControls/DynamicDocumentsUserControl.ascx") as UserControls.DynamicDocumentsUserControl;

This worked just fine.