Question

I have a basic TextBox on a user control I am dynamically loading. I figured out how to push a value to this TextBox. The problem I am running into is that I can’t get the entered value from this TextBox.

I had to create a class to pass variables to/from the dynamically loaded control. I called it PBUserControl.

public class PBUserControl : UserControl
{
    public IList<NVP> NameValuePairs { get { return _NameValuePairs; } }

    public class NVP
    {
        public NVP() { }
        public NVP(string name, string value)
        {
            this.Name = name;
            this.Value = value;
        }
        public string Name { get; set; }
        public string Value { get; set; }
    }
}

This seems to work just fine for sending data into the user control.

My Dynamically loaded user control:

public partial class Basic : PBUserControl 
{
    protected void Page_Load(object sender, EventArgs e)
    {
        if (this.IsPostBack == false)
        {
            this.InitializeControl();
        }
        else
        {
            this.ProcessSubmit();
        }
    }

    private void InitializeControl()
    {
        DynamicLiteral.Text = "Some Dynamic Content. " + GetNameValue("TestContent");
        TestTextBox.Text = GetNameValue("Test");
    }
    private void ProcessSubmit()
    {
        AddNameValuePair("TestContent", "Passing back some value... "+ DynamicLiteral.Text);
        AddNameValuePair("Test", TestTextBox.Text);
    }
}

Here is the page calling and including this Dynamically loaded control:

public partial class PageAddEdit : PageBase
{
    private PBUserControl _PBUserControl;

    protected void Page_Load(object sender, EventArgs e)
    {
        // Must always desigante the control here else it dissapears.
        Control TemplateUserControl = LoadControl("~/Administrator/PageBuilder/Templates/Basic.ascx");
        _PBUserControl = (PBUserControl)TemplateUserControl;
        _PBUserControl.AddNameValuePair("TestContent", "It is working!!!!!!!!!");
        _PBUserControl.AddNameValuePair("Test", "Some test text.");
        Template.Controls.Add(TemplateUserControl);
    }

    protected void MenuGroupRadMenu_Clicked(object sender, EventArgs e)
    {
        IList<PBUserControl.NVP> nvp = _PBUserControl.NameValuePairs;
    }
}

Let me explain what is going on here. I can set the values in the PBUserControl from the main page. It passes into the Dynamically loaded user control perfectly. Does what it is supposed to do. Works wonderfully.

However, the page_load event within the dynamically loaded control is being fired before the postback variables are processed. So at that point the contents of the TextBox is not even read yet. I found this out through research. Also, if I put a Pre_Rendered event within the Dynamically loaded control I can see the value of the TextBox when stepping through the code with the debugger. Also, with the debugger I can see that the TextBox is not read during the Page_Load event. My research lead me to the following:
1. Page_Init event is called
2. Page_Load event is called
3. Page form variables are read and processed (Not sure what event)
4. User Events are called ie: OnClick
5. Pre_Rendered event is called.

I need to be able to create an event that will be called after step 3 and before or during step 4. That way I can capture the TextBox value and set it’s value within the PBUserControl.NVP variable so it can be read by the main page. If I manually set a value in the PBUserControl.NVP variable, it is seen by the main page and is read just fine.

Thanks in advance.

Answer 1

I figured it out!!!! Basically I created an event and passed it from the Dynamically loaded UserControl to the Main UserControl. Below are the changes I made to get it to work. Quick explanation so everyone can follow along with how it works. I have an outer wrapper called PBUserControl that allows me to create some elements through inheriting. The idea behind is to allow me to pass data back and forth and apparently an event. When dynamically loading a child control you are no longer afforded the luxury of easily tying elements nor events. The PBUserControl class creates a common bond that allows this to work. For my purposes it is setup to ideally work for how the data structure is setup on the back end. So making tweaks will be required to make it work for you. But this should prove to be an easy to follow concept.

I am able to register an action within the dynamic control to the ControlSubmittedHandler located in PBUserControl.

I am able to register the action from the dynamic control in the parent control by assigning the ControlSubmittedHandler through the ControlSubmittedDelegate into a local event. At that point I am able to trigger that event.

Enough explanation, here are the code changes to make it work:

I added the following to the class PBUserControl:

public delegate void ControlSubmittedDelegate(object sender, EventArgs e);
public System.EventHandler ControlSubmittedHandler;

Within my dynamically loaded control I changed the Page_Load event to:

protected void Page_Load(object sender, EventArgs e)
{
    InitializeControl();
    this.ControlSubmittedHandler = new EventHandler(ControlSubmittedAction);
}

Within my dynamically loaded control I added:

public void ControlSubmittedAction(object sender, EventArgs e)
{
    ProcessSubmit();
}

Within my main control I added:

private PBUserControl _PBUserControl;
private event PBUserControl.ControlSubmittedDelegate myEvent;

Within my main control I changed:

protected void MenuGroupRadMenu_Clicked(object sender, EventArgs e)
{
    myEvent = new PBUserControl.ControlSubmittedDelegate(_PBUserControl.ControlSubmittedHandler);
    if (myEvent != null) myEvent(this, e);

    IList<PBUserControl.NVP> nvp = _PBUserControl.NameValuePairs;
}