Question

My asp.net application has a custom base user control that is inherited from other user controls. This custom base user control has three properties that have been made public. When the user control is loaded the custom base user control properties are null. I am trying to figure what I am doing wrong. can someone please help figure out what step I am missing?

custom base user control loading code from parent page:

    private void Render_Modules()
    {
        foreach (OnlineSystemPageCustom.OnlineSystemPageHdr.OnlineSystemPageModule item in custompage.Header.Modules)
        {
            if (item.ModuleCustomOrder != 99)
            {
                webonlinecustombase ctl = (webonlinecustombase)Page.LoadControl("../IPAM_Controls/webtemplatecontrols/webonlinecustombase.ascx");
                ctl.Event = Event;
                ctl.custompage = custompage;
                ctl.custommodule = item;
                this.eventprogrammodules.Controls.Add(ctl);
            }
        }
    }

custom base user control code behind

public partial class webonlinecustombase : System.Web.UI.UserControl
{
    public Event Event { get; set; }
    public OnlineSystemPageCustom custompage { get; set; }
    public OnlineSystemPageCustom.OnlineSystemPageHdr.OnlineSystemPageModule custommodule { get; set; }

    public void Page_Load(object sender, EventArgs e)
    {
        string typeName = custommodule.ModuleInternetFile;
        inpagelink.HRef = "#" + custommodule.ModuleName.Replace(" ", "").Replace("/", "");
        modtitle.InnerText = custommodule.ModuleName;
        Type child = Type.GetType(typeName);

        UserControl ctl = (UserControl)Page.LoadControl(child, null);
        if (ctl != null)
        {
            this.modsection.Controls.Add(ctl);
        }
    }
}

sample code of user control inheriting base user control

public partial class eventscientificoverview : webonlinecustombase
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (custommodule.ModuleDefaultVerbiage != null && custommodule.ModuleDefaultVerbiage != "") { this.Load_Verbiage(false); }
        else if (custommodule.ModuleCustomVerbiage != null && custommodule.ModuleCustomVerbiage != "") { this.Load_Verbiage(true); }
    }

    protected void Load_Verbiage(bool usecustom)
    {
        if (usecustom) { this.scientificoverviewverbiage.InnerHtml = custommodule.ModuleCustomVerbiage; }
        else { this.scientificoverviewverbiage.InnerHtml = custommodule.ModuleDefaultVerbiage; }
    }
}

Answer 1

You must call Render_Modules in the init event of the parent page.

Also, you may want to restructure your base/custom classes to avoid event execution order confusion since the load event will be fired in both the base and the custom classes.

Any time we have this type of structure, we always implement an OnLoad method in the base class for inheritors to override. This way we can control exactly when the Load logic is executed in the inheritors.

Updated with additional info

Here is some additional information on how to handle the load events in base and child classes.

In webonlinecustombase, add the following:

protected virtual void OnPageLoad() {
}

then modify your page load event to call this new method at the appropriate time:

public void Page_Load(object sender, EventArgs e)
{
    string typeName = custommodule.ModuleInternetFile;
    inpagelink.HRef = "#" + custommodule.ModuleName.Replace(" ", "").Replace("/", "");
    modtitle.InnerText = custommodule.ModuleName;
    Type child = Type.GetType(typeName);

    UserControl ctl = (UserControl)Page.LoadControl(child, null);
    if (ctl != null)
    {
        this.modsection.Controls.Add(ctl);
    }

    // Now let the inheritors execute their code
    OnPageLoad();
}

then, in your inherited class, change:

protected void Page_Load(object sender, EventArgs e)

to

protected override void OnPageLoad()

As I was reviewing this code, I discovered that you are also dynamically loading controls in webonlinecustombase. You will need to move the loading of the controls into the init event in order for them to work correctly in the standard page logic.