Literal control rendering empty

[paul.hester]

Hi all,

I have a custom control with an overridden Render method. Inside this
method I'm rendering each control in its collection using their
RenderControl method. However, I'm running into a problem in this
scenario:

<myprefix:mycontrol runat="server">
<%= SomeVariable %>
</myprefix:mycontrol>

The contained control is showing up in the control collection as a
LiteralControl, but its Text property is empty. Well, it's a series of
spaces, so it's not showing up with any content. I can put <%=
SomeVariable %> anywhere outside my custom control and it will render
the variable value correctly.

Is there anything I can do to ensure the variable value is rendered?

I hope this post makes sense!

Thanks,

Paul

 

[Alessandro Zifiglio]

hi Paul, it is my thinking that the expression is already written out to the
output stream, and that the evaluation of the expression is not deposited in
the containing .aspx page at a suitable time for usage by your control and
as such cannot make much use of it.
Reference msdn online about this particular inline code construct here :
http://msdn2.microsoft.com/en-us/library/6dwsdcf5.aspx

If you want to simply support adding text in btw your controls tags or
support nesting of child elements, then you want to make a new class that
inherits the ControlBuilder and associate your custom control with this.
Here is an example of how to use the ControlBuilder :
http://msdn2.microsoft.com/en-us/library/system.web.ui.controlbuilder.aspx

Regards,
Alessandro Zifiglio
http://www.AsyncUI.net

 

[Alessandro Zifiglio]

Auto-Correction :
You are unable to get the value of the inline codeblocks expression syntax
<%= %> since the default ControlBuilder does not pass back anything.
Instead, on the other hand, the built in ControlBuilder has support for
databinding expression syntax<%# %> allowing you to retrieve this value. It
makes the value available as a DataBoundLiteralControl. Note that to get the
value, it needs to added to your controls, control collection first, and
then reference the control in the collection in a phase after the
DataBinding phase in your controls life cycle.

Regards,
Alessandro Zifiglio
http://www.AsyncUI.net