如何从单个.ascx文件在ASP.net页中加载多个用户控件

Question

I try to use custom control with .ascx file to load mutliple controls in ASP page, on click button event.

Here is my .ascx file :

<%@ Control Language="VB" ClassName="CHelloWorld" %>
<script runat="server">
</script>

<asp:Panel ID="panel" runat="server">
    hello world!
</asp:Panel>

Now I create a .aspx file with a button, and a panel in which I add controls every time use click on button :

<asp:Panel runat="server" id="panelcontrols">
</asp:Panel>
<asp:Button id="myButton" OnClick="OnClickButton" Text="Add" />

And here is my .vb file with click event :

Sub OnClickButton(ByVal sender As Object, ByVal e As System.EventArgs)
    Dim myControl As Control
    myControl  = LoadControl("myfile.ascx")
    panelcontrols.Controls.Add(myControl  )
End Sub

With this implementation, when I click first time : I see "Hello World!" in my page, but when I click second time, third time, ... No change happen !

Is it because I can load only one control from .ascx ?

How can I create multiple controls from single .ascx file ?

Thanks.

[EDIT]

OK, I use now WiewState to remember controls already created. Thanks.

But I have a question :

My .aspx file use code in .vb file (where I have defined OnClickButton) with this line in @Page directive : Src="[path]/myscript.vb

But in this .vb file I don't know how to use CHelloWorld control type, to modify control properties.

If I use this code it doesn't work :

Sub OnClickButton(ByVal sender As Object, ByVal e As System.EventArgs)
    Dim myControl As CHelloWorld
    myControl  = LoadControl("myfile.ascx")
    panelcontrols.Controls.Add(myControl  )
End Sub

It fails saying "CHelloWorld" is not defined !

How can I do ?

Answer 1

No, it's because you are adding the control dynamically. On each page load the added control will be lost so you need to add it each time (and thus have a way of "remembering" what you added between postbacks)

Answer 2

I'm glad the ViewState worked for you.

Regarding the next issue, have you got the correct namespace? (It may be worth asking this in a separate question)