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C# ASP.NET - Dynamic MenuItems in a user control are randomly being duplicated outside of control creation

EDIT: I needed to skip control creation during post back -- see my answer below.
I'm working on a very basic front end to a simple tool and I wanted to present some data in a much more sorted and useful way, instead of making one huge wall of text. I found this tutorial on building a simple tabbed interface using MultiView, but have run into a bizarre problem. I can't use Ajax tabs because of legal hissy fits over 3rd party software.
My webpage is a basic ASP.NET page with a user control plopped in the middle of it. In this control's ascx file, I defined the Menu (empty) and the MultiView (also empty) so that I can dynamically populate the tabs with content driven from an external file.
When the default page's OnInitComplete function is called, I call through to the user control to load the data file, then build out the tabs and the view content based on the loaded data. I tried doing this from PageLoad, PreInit, and CreateChildControls, but I kept getting an errors saying that I was setting the the MultiView's active view index at an invalid time (and also that there were 0 views despite the fact I just added a bunch of them):
ActiveViewIndex is being set to '0'. It must be smaller than the
current number of View controls '0'. For dynamically added views, make
sure they are added before or in Page_PreInit event.
But OnInitComplete appears to work just fine, so I went with that.
I iterate over the loaded data (multiple lists of strings), and for each list, I add a MenuItem with the list's title to the Menu and a View to the MultiView. The View is populated with a table->row->cell as in the above tutorial. In the cell, I add the list title and a CheckBoxList data bound to the list of strings.
So far so good, but when I click on a tab (or one of the checkboxes, etc) and there is a postback or something like that (the screen flashes as the site redraws itself), there is now a duplicate set of MenuItems immediately after the original. Each time I click on a tab or checkbox, another set of menu items are added.
I clear the MenuItem's Items list prior to building the controls and I verify that the controls hierarchy is structurally as expected after the control construction. Yet when one of my callbacks is called, my MenuItem list magically has some items added to it. None of my other controls appear affected at all. As a hack, I can remove the duplicates manually in my menu's OnMenuItemClick event, but I'd have to do the same in any of the callbacks I receive. Obviously I'd rather prevent this from happening. This has me stumped and I haven't been able to find anything online about it. Why would one set of controls have some content duplicated, yet every other control maintain its state correctly? My code is really simple so there isn't a way to add additional menu items without also adding the views. Anyway, there are a correct number of items prior to clicking on the tab/checkbox, an additional set immediately following in the callback.
This is my first time using ASP.NET, so I'm learning as I go. :) Thanks!

My problem was that I was not testing for postback before creating the controls. The code below is working for me.
In my user control's code behind:
protected void OnInitComplete( EventArgs e )
{
if( !Page.IsPostBack )
{
CreateMyControls();
}
}

Moving Controls from One Tab Page to Another

I currently am working on a WinForm project in which there are several different tabs. Within each tab there are various controls such as buttons, sub-tabs, text-boxes, ect...
I need to consolidate the overall application which involves taking certain controls from one tab and moving them to another. When I first tried doing so, I simply copy and pasted the controls. As you can imagine this didn't work due to the fact that I didn't move the properties with the controls, I really just created NEW ones on a different tab. Therefore when I complied the code, nothing worked because there was no code assigned to the new controls.
When I tried it again, this time I CUT and paste which also maintains the same properties as the old controls (specifically the reference name in the code), so as far as I can tell, the code should identify the controls by name, and apply the same actions. However, when I compile the code, the application successfully builds but the controls do not perform any actions.
At this point I am not sure what to do...

Use the Document Outline.
View... Other Windows... Document Outline.
Select the required component and drag it from one tab page to the other in the tree control. I did this and the actions are preserved in the new tab page.

Drag the item out of the tab control and onto the form itself. Change to the other tab. Then drag the item into that tab. It is essentially 2 drag moves, but since you do not ever cut, all code linking is maintained. If your tab control takes up the entire form, simply make it smaller while you do the preceding steps and then make it large again when you are done.

When you "cut" the controls, you sever the connections between the controls and their respective events. When you "paste" them again, they're not hooked up to the events anymore, so they don't appear to do anything.
The "event" methods should still be present in your code, but you'll have to manually go through and subscribe each event to each control again (via the Properties window).
Alternatively, revert those changes, then open the .Designer.cs file and look for something like this:
this.tabPage1.Controls.Add(this.dataGridView1);
Which (for example) places dataGridView1 inside tabPage1.
If you wanted to move the DataGridView to another TabPage, you could just change this.tabPage1 in the above code to this.tabPage2.
this.tabPage2.Controls.Add(this.dataGridView1);
Then you can flip back over to the designer view and move the control around to wherever you want it within the TabPage.

I just tested it. What is happening when you cut and paste your controls, you losing the wiring of the events. What you need to do after cut and paste is to go to control properties-events, find the event in question and on the right, select a method that you want to handle that event.

This will cut them from the first TabPage and paste them on the second, i think you can do this as often as you want. And with a small change you can make it a truly copy.
hope it helps
private void ControlsToTabPage(TabPage from, TabPage to)
{
Control[] ctrlArray = new Control[from.Controls.Count];
from.Controls.CopyTo(ctrlArray, 0);
to.Controls.AddRange(ctrlArray);
}

Maintain the state of dynamically added user control on postback?

I have a user control that contains only a text box and on another form I add this user control dynamically, a user can add the user control many times. I use a session variable to recreate the user control (maybe this approach doesn't sound cool). After recreating the control the value of the textbox disappears, obviously. Is there any solution to maintain the state of the user control on postback?

If you add dynamic controls back to the control during the correct Page Life Cycle event(PreInit) they will maintain their state through the IPostBackDataHandler interface.
PreInit - Create or re-create dynamic controls.

I've had the same problem in the past.
What I did was give the dynamically-added control an ID, and made sure it retained that ID also on postback (in my case, I kept all the information in the session, and re-created the controls).
Once the postbacked control has the same ID as as before, Microsoft did magic and refilled the controls with the pre-postback values.

Use the object cache. Add the usercontrol into the cache and retrieve it when you need it.
You can see a nice example of how this works at: ASP.net-Tutorials Cache and Object Cache.
I am also learning asp.net now and found that quite a nice explanation. I also used the Microsoft Library

Every server control that inherits the IPostBackDataHandler interface has a LoadPostData method that processes the postback data. When control is implemented by a class (page, form, placeholders, controls etc), that class calls the LoadPostData method and passes the posted data and key to maintain control states.
All you need to do is to re-instantiate / reinitialize dynamic controls before or within page load event each and every time during postback and add this control to page / forms / placeholders. Then the posted data will automatically be assigned to the control by calling LoadPostData method by the parent control.
Check this article to learn how to write code for dynamic control -
How to maintain dynamic control events, data during postback in asp.net

How to append controls to a panel?

I am developing a dynamic website in ASP.NET. As a trial I tried a code shown below, that adds some controls to Panel1. When user clicks a button for the first time the controls are added to the Panel but when user clicks the same button for second time, the previous controls are replaced with new ones. But I want the controls to be appended one after the other each time the user clicks the button. The code is something like this:
Control c=Page.LoadControl("DData.ascx");
Panel1.Controls.Add(c);
I also tried
Control c=Page.LoadControl("DData.ascx");
Panel1.Controls.AddAt(Panel1.Controls.Count,c);
But this replaces the first output. Please tell me how to append these controls?

As you would expect, this appends a single control:
Control c = Page.LoadControl("DData.ascx");
Panel1.Controls.Add(c);
You can append as many controls as you wish in this fashion.
However, you need to keep track of the controls you are adding in some persisted/stateful fashion (database, Session, ViewState, etc.).
You need to rebuild the control tree every time the page loads.
See my answers to similar questions:
https://stackoverflow.com/a/10050755/453277
https://stackoverflow.com/a/9545079/453277

It may be about the life cycle of asp.net page. Each time when page loads it returns to the initial state. Button Click events are handled after page load and you have only one control at the page. Please look Button to dynamically add controls everytime it's clicked

Using Page.IsPostback Within a User Control Wrapped in an Update Panel

I have a main page into which i load a user control with a grid and add/edit link buttons.
If I bind the grid by setting the datasource and calling the databind() method in the page load event then it sets properly. However, I want to keep the selected row between postbacks, so I wrap the bind code in "if (!Page.IsPostBack) {}" as usual. My problem is the page load always registers it as a postback and my code never runs.
I am using the 2.0 framework, and my grid is an 2008.1 Infragistics for the 2.0 framework.
I thinking this must be something simple.... or hoping anyway!
Thanks in advance

If you place your control into an UpdatePanel, then you should check for Page.IsCallback instead of Page.IsPostBack.

The two ways I found round this were:
to load the user controls when the page is first loaded and then hide them until user selected what they need to see.
to load a new page into an iframe on the main page allowing it to have its own page control meaning when its loaded in at first its not a postback.
Not the greatest, but gets by.
Thanks for the help.

I have mixed feelings about necroing a thread this old, but the question is still relevant, and there weren't any great solutions offered, so though I would add what I recently did to solve the same issue:
I had a similar problem with a site I was building. My solution was to add a method to the user control called "OnFirstLoad" that does all of the stuff I would have wrapped in an "if not Page.IsPostback" block. I then call the "OnFirstLoad" method from the hosting page the first time the control is loaded into the control tree. This way the control itself doesn't have to worry about whether or not this is a postback, and the main page can initialize it as needed.