When to override Render

[Allan Ebdrup]

We're pretty new to ASP.Net 2.0 and we're having a discussion about best
practice when developing custom server web controls.
I can see that in for example the Wizard control the table contained within
is a control and all the children are controls.
That seems to be a good practice to me, use controls when possible.
On the other hand one of the developers here wants to override the Render
methods and create child tables with strings and a HtmlTextWriter.
In my view that introduces a lot of problems since you can easily make a
mistake in the Html you output, and you don't get any programatical access
to all the children that you have if you use controls.
On the other hand the developer here thinks that all those controls make a
mess, he just want the children of the control to be the stuff that actually
matters, not stuff like tables that are just there for layout purposes.

What's your take on this? What's a good practice? Use controls whenever
possible and only override the Render methods when you absolutely have to?
Or override the render methods every time you can?

Kind Regards,
Allan Ebdrup

[John Timney \(MVP\)]

Controls whenever possible. Overriding render should be done only when you
need to, just like developing any code.

Regards

John Timney (MVP)
http://www.johntimney.com
http://www.johntimney.com/blog
"Allan Ebdrup" <eb****@noemail.noemailwrote in message
news:%2***************@TK2MSFTNGP02.phx.gbl...

We're pretty new to ASP.Net 2.0 and we're having a discussion about best
practice when developing custom server web controls.
I can see that in for example the Wizard control the table contained
within is a control and all the children are controls.
That seems to be a good practice to me, use controls when possible.
On the other hand one of the developers here wants to override the Render
methods and create child tables with strings and a HtmlTextWriter.
In my view that introduces a lot of problems since you can easily make a
mistake in the Html you output, and you don't get any programatical access
to all the children that you have if you use controls.
On the other hand the developer here thinks that all those controls make a
mess, he just want the children of the control to be the stuff that
actually matters, not stuff like tables that are just there for layout
purposes.

What's your take on this? What's a good practice? Use controls whenever
possible and only override the Render methods when you absolutely have to?
Or override the render methods every time you can?

Kind Regards,
Allan Ebdrup

[Peter Bucher [MVP]]

Hi John, hi Allan

Controls whenever possible. Overriding render should be done only when you
need to, just like developing any code.

I agree with you: when you need to!

Its important to know, whats really goin on.
Use .NET Reflector for this.

The Render Methode looks like:
-----
protected internal override void Render(HtmlTextWriter writer)
{
this.RenderBeginTag(writer);
this.RenderContents(writer);
this.RenderEndTag(writer);
}
-----

As you`ll see, overwriting the Render Methode prevent the execution of these
three methods.
If you got a Tag around your Control, then better overwrite these three or
one of these, if needed.
Otherwise inherit from Control and overwrite the Render Method.

--
Gruss, Peter Bucher
Microsoft MVP - Visual Developer ASP / ASP.NET, Switzerland
http://www.aspnetzone.de/ - ASP.NET Zone, die ASP.NET Community
http://www.aspnetzone.de/blogs/peterbucher/ - Auf den Spuren von .NET

[Walter Wang [MSFT]]

Hi Allan,

I agree with John and Peter here.

For some crash courses on developing ASP.NET custom server controls, you
may find following articles useful:

#Creating Controls
http://msdn2.microsoft.com/en-us/library/aa530687.aspx
Hope this helps.
Regards,
Walter Wang (wa****@online.microsoft.com, remove 'online.')
Microsoft Online Community Support

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