Web Forms

Re: Problem with UserControl

cheng_jiawei — Sun, 26 Oct 2008 04:00:14 GMT

It's LoadControl Source Code:

1    private Control LoadControl(IWebObjectFactory objectFactory, VirtualPath virtualPath, Type t, object[] parameters)
2    {
3        BuildResultCompiledType type = null;
4        BuildResultNoCompileUserControl control = null;
5        PartialCachingAttribute cachingAttribute;
6        if (objectFactory != null)
7        {
8            type = objectFactory as BuildResultCompiledType;
9            if (type != null)
10           {
11               t = type.ResultType;
12               Util.CheckAssignableType(typeof(UserControl), t);
13           }
14           else
15           {
16               control = (BuildResultNoCompileUserControl) objectFactory;
17           }
18       }
19       else if (t != null)
20       {
21           Util.CheckAssignableType(typeof(Control), t);
22       }
23       if (t != null)
24       {
25           cachingAttribute = (PartialCachingAttribute) TypeDescriptor.GetAttributes(t)[typeof(PartialCachingAttribute)];
26       }
27       else
28       {
29           cachingAttribute = control.CachingAttribute;
30       }
31       if (cachingAttribute == null)
32       {
33           Control control2;
34           if (objectFactory != null)
35           {
36               control2 = (Control) objectFactory.CreateInstance();
37           }
38           else
39           {
40               control2 = (Control) HttpRuntime.CreatePublicInstance(t, parameters);
41           }
42           UserControl control3 = control2 as UserControl;
43           if (control3 != null)
44           {
45               if (virtualPath != null)
46               {
47                   control3.TemplateControlVirtualPath = virtualPath;
48               }
49               control3.InitializeAsUserControl(this.Page);
50           }
51           return control2;
52       }
53       HashCodeCombiner combinedHashCode = new HashCodeCombiner();
54       if (objectFactory != null)
55       {
56           combinedHashCode.AddObject(objectFactory);
57       }
58       else
59       {
60           combinedHashCode.AddObject(t);
61       }
62       if (!cachingAttribute.Shared)
63       {
64           this.AddStackContextToHashCode(combinedHashCode);
65       }
66       string combinedHashString = combinedHashCode.CombinedHashString;
67       return new PartialCachingControl(objectFactory, t, cachingAttribute, "_" + combinedHashString, parameters);
68   }
69   
70    
71   
72    
73

Re: Problem with UserControl

cheng_jiawei — Sun, 26 Oct 2008 03:46:12 GMT

I Googled....

When you load a control, you do more than instantiate it..

new RegInfo();, as you know, creates a new instance of a class.

Page.LoadControl also creates a new instance, but also does a lot
more...such as bringing the control up to the same event life cycle. AS you
can imagine, if new did this, it would be inconsitent with how new works for
normal classes (simply calling the constructor...).

Cheers,
Karl

Re: Problem with UserControl

easter — Sun, 26 Oct 2008 03:35:09 GMT

Thanks, that did work. Although, I don't see why I need to use Page.LoadControl rather than just using the constructor of the control. Oh well, thanks :)

Re: Problem with UserControl

cheng_jiawei — Sun, 26 Oct 2008 03:31:20 GMT

:) I build a demo,and find out your problem!

See my demo:

You shold create usercontrol like this: Page.LoadControl()

1            protected void Page_Load(object sender, EventArgs e)
2            {
3                for (int i = 0; i < 10; i++)
4                {
5                    UserControl usercontrol = (UserControl)Page.LoadControl("~/UserControl.ascx");
6                    usercontrol.Name = i.ToString();
7                    this.pnlControl.Controls.Add(usercontrol);
8                }
9            }
10

1        public partial class UserControl : System.Web.UI.UserControl
2        {
3    
4            private string _name;
5    
6            public string Name
7            {
8                set
9                {
10                   _name = value;                
11               }
12               get { return _name; }
13           }
14   
15           protected void Page_Load(object sender, EventArgs e)
16           {
17               this.LblText.Text = _name;
18           }
19       }

1    <%@ Control Language="C#" AutoEventWireup="true" CodeBehind="UserControl.ascx.cs" Inherits="WebProjects.UserControl" %>
2    <div>
3        <span><asp:Label ID="LblText" runat="server"></asp:Label></span>
4    </div>
5

Re: Problem with UserControl

easter — Sun, 26 Oct 2008 02:51:59 GMT

That didn't work. I've also removed all the link buttons btw, and made them into <a> tags, with a runat server to set their href on load.

Re: Problem with UserControl

cheng_jiawei — Sun, 26 Oct 2008 02:44:18 GMT

I think you'd better Add your UserControls in Panel Control(Server),just try.

I think your coding is ok, but if you want to click the link button in your controls ,it will be post back.

Re: Problem with UserControl

easter — Sat, 25 Oct 2008 01:59:23 GMT

No post back is occuring. The problem occurs on the initial load of the page.

Re: Problem with UserControl

cheng_jiawei — Sat, 25 Oct 2008 01:57:49 GMT

I think the problem is that :where and when you created your UserControls?

Just as you see, everytime you postback your page,the UserControls that your added are completed lost(So is null).

Yet,I got that problems before.

I think it's better to create Client Controls instead of UserControl in the server.

Or you have to create the UserControls everytime In the Page_Load event :)

Hope that help~

Re: Problem with UserControl

jorr1027@cox.net — Sat, 25 Oct 2008 01:19:37 GMT

Are you dynamically adding userControls to the aspx page itself?

If so for every userControl added you have to add another <qcc:qccntrl ID="QuoteControlID" runat="server" /> to the aspx page.

Possible solutions:

1) on aspx postback use a for loop to:

append a number to QuoteControlID incrementing the ID, building the "<qcc:qccntrl ID=""QuoteControl""" + i + " runat=""server"" />" string and use an HTMLWriter to add it to the aspx page. When the page Renders it may show the correct amount of controls.

2) add the maximum number of quoteControls allowed to the aspx page, on Init disable whatever is not needed yet, on postback enable as many userControls as needed.

Re: Problem with UserControl

easter — Sat, 25 Oct 2008 01:05:43 GMT

Normally, like the Ajax controls, I would statically put them in the page, but unfortunately I need to dynamically create the controls, as I won't know how many will be needed.

Thanks for trying though :)

Re: Problem with UserControl

jorr1027@cox.net — Sat, 25 Oct 2008 01:00:44 GMT

easter:

EDIT: You edited your posts :P

Okay, I see what you mean. The code you posted is in my ASCX page, not ASPX. Was a typo in my first post, sorry.

ah! I'm taking to long to check my references. It seems my advice cannot help :(

Re: Problem with UserControl

easter — Sat, 25 Oct 2008 00:43:05 GMT

EDIT: You edited your posts :P

Okay, I see what you mean. The code you posted is in my ASCX page, not ASPX. Was a typo in my first post, sorry.

Re oops

jorr1027@cox.net — Sat, 25 Oct 2008 00:25:34 GMT

Re: Problem with UserControl

jorr1027@cox.net — Sat, 25 Oct 2008 00:25:34 GMT

Doh, I did not realize you were referencing your Controls code behind from the aspx file. My bad, ... It was my understanding that UserControls are for writing once what is used often, like the items in the AJAX control toolkit. I always put my asp controls on my UserControl.ascx page and put the code behind in my UserControl.ascx.cs page. I Place the <qcc:qccntrl ID="QuoteControlID" runat="server" /> on the aspx page and any other controls the UserControl might interact with, the aspx.cs code behind handles the interaction between the UserControl and the aspx controls

The aspx page is "hosting" the ascx control...

Re: Problem with UserControl

jorr1027@cox.net — Sat, 25 Oct 2008 00:25:34 GMT

Instead of this in your aspx page:

<ContentTemplate>
        Quote
        <asp:LinkButton ID="lnkQuote" runat="server" onclick="lnkQuote_Click">a</asp:LinkButton>
        Score: <asp:Label id="lblScore" runat="server">a</asp:Label> [
        <asp:LinkButton ID="lnkUp" runat="server" Text="+" CommandArgument="up"
                onclick="lnkUp_Click">a</asp:LinkButton> /
        <asp:LinkButton ID="lnkDown" runat="server" Text="-" CommandArgument="down"
                onclick="lnkDown_Click">a</asp:LinkButton> ]
        - Submitted: <asp:Label ID="lblTime" runat="server">a</asp:Label>
        <asp:Label ID="lblError" runat="server">a</asp:Label>
    </ContentTemplate>

Only put:

<qcc:qccntrl ID="QuoteControlID" runat="server" />

</ContentTemplate>