Hi,

I've installed Visual Web Developer 2005 Express, and I've created a web site and done various things. I'm trying to get a little more in depth, so I thought I'd do the old trick with access, where you set a break point and look at the values in the objects.

I've created a treeview control, and set a breakpoint on the 'load' event. Using c#, the two parameters are sender (object) and e (EventArgs). Looking in the 'locals' view, I can see the 'sender' variable, and it contains a number of elements, e.g. CollapseImageUrl, ExpandDepth etc.

In the immediate window, if I type:

?sender.ExpandDepth

I get the error message "'object' does not contain a definition for 'ExpandDepth'"

Can someone tell me where I'm being stupid? - I can see 'sender' with the attribute 'ExpandDepth' has the value of '0' in the locals window, so how come I can't get at it in the immediate window?

Many thanks in advance

Carl.
 

Hi,

This is because the type of sender is System.Object, and Object type does not has any member by the name of ExpandDepth. You need to cast the sender to the appropriate object in order to use its properties, for example:

((Page)sender).ID

Hope this helps,

Vivek

Many thanks,

I'll give that a try - but it still puzzles me - you don't need to cast the object within the actual code, so how come you need to cast it in the immediate window? - or should the object be cast'ed within the code too (if so, then a number of examples on the web should need updating!)

 
Maybe I'm being too pedantry...

Carl.
 

Carl,

Immediate windows runs the evaluation expression independently. It is like a sort of mini execution screen. Even in the watch window if you try to execute sender.SomeProperty, it will give you an error, and you DO need to cast the object in the code. Its simple, unless you cast it you won't be able to access the actual type related properties at runtime.

The lcoals view already "knows" about the object and it simply shows the properties via reflection (I think so). But in code or Immediate window, you need cast it accordingly.

 HTH

Vivek