Writing container controls

Question

User967840515 posted
How can you write a custom control that can contain other controls?

As a trivial example, say I wanted a red square that could hold an asp:Button.

The control would be something like

[DefaultProperty("Text"), ParseChildren(true, "Text")]
public class RedSquare : WebControl
{
    ...
}

and the RenderContents method could just render a div with a red background and the "Text" property in it.

This seems to work fine for normal text but I can't add child controls to it. For example, I can't do

<mycontrol:RedSquare runat="server"><asp:Button Text="press me" runat="server" /></mycontrol:RedSquare>

Is there any way to do this so that I can put a control <...>here</...>

Answer 1

User2032526919 posted

Hi,

that would be a templated server control e.g a control having template property to which you can put other controls / speciofy them in markup and they are added and used by the control

I've written some posts in the past demonstrating such:

ASP.NET: Implementing designer for a templated server control
http://aspadvice.com/blogs/joteke/archive/2006/08/13/20573.aspx

Templated Composite Controls
http://aspadvice.com/blogs/joteke/archive/2006/11/19/Templated-composite-controls.aspx

 

Answer 2

User481221548 posted

Hi there

Using a Panel with a custom CSS-class would be the easiest one :-)
For all other things i agree with teemu and would too using templates for that.

Answer 3

User967840515 posted

Hi there

Using a Panel with a custom CSS-class would be the easiest one :-)

Unfortunately, a red square was a trivial example. What I want to do is not possible with just a panel and some CSS.

I'll look into templates.

Answer 4

User967840515 posted
I've tried these but I can't seem to get any further than I already was. If I take the simple example from the top of http://aspadvice.com/blogs/joteke/archive/2006/08/13/20573.aspx and then use it as follows:

<%@ Register Namespace="TemplateControls" TagPrefix="templates" %>

...

<templates:SimpleTemplateControl ID="mytemplate" runat="server">
    <asp:Label ID="mylabel" runat="server">foo</asp:Label>
</templates:SimpleTemplateControl>

It gives me an error on the asp:Label line:
Parser Error Message: Type 'TemplateControls.SimpleTemplateControl' does not have a public property named 'Label'.

If I change that to

<templates:SimpleTemplateControl ID="mytemplate" runat="server">foo</templates:SimpleTemplateControl>

then I get the error:
Parser Error Message: Literal content ('foo') is not allowed within a 'TemplateControls.SimpleTemplateControl'.

---

Edit: Never mind, I didn't realise that you needed to use

<templates:SimpleTemplateControl ID="mytemplate" runat="server">
    <SimpleTemplate>... foo ...</SimpleTemplate>
</templates:SimpleTemplateControl>

Thanks :)

P.S. Has anyone else noticed that on this board the "Preview" tab seems to produce normal sized text but the topic itself seems to make it significantly smaller?