Inheriting problem...I think

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YYZ

I'm new to VB.net, but not new to OO in general, and I'm very strong in VB6.
However, I don't know what I did in VB.net to cause this to happen.

I've got 2 projects open at the same time, in the same solution. One is a Class
Library project that contains 1 form and 1 class. The other project is a normal
Windows app, and contains 2 forms, both inherited from the form in the class
library, by adding the line "Inherits PCG.ClassLib.frmPCGGen (yeah, that's my
testing root namespace, and frmPCGGen is just a temporary form name while
testing out all this inheritance stuff).

Well, yesterday I could have sworn things were working fine, but today, if I try
to open up any of the forms to add controls to them, I get an error message
(actually, sometimes 2), first is "Object reference not set to an instance of an
object" on line 0, no filename...

Now that I think of it, here's what I did. I added code into the frmPCGGen (in
the class library) to save the settings of the form to the registry. To do
this, it basically looks into the EntryAssembly...well, I'm assuming that this
is a problem, since, when viewing in the designer, there IS no entry assembly.

Does that sound about right to anyone? Is there anyway I can figure out if the
code is trying to run when instantiated in the designer vs running compiled?
Anyone else run into this, and have an elegant solution for me?

Matt
 
Now that I think of it, here's what I did. I added code into the frmPCGGen (in
the class library) to save the settings of the form to the registry. To do
this, it basically looks into the EntryAssembly...well, I'm assuming that this
is a problem, since, when viewing in the designer, there IS no entry assembly.

Does that sound about right to anyone? Is there anyway I can figure out if the
code is trying to run when instantiated in the designer vs running compiled?
Anyone else run into this, and have an elegant solution for me?
Click to expand...

I think I solved the problem, sorry for posting, especially with a subject that
wasn't representative (I changed my question as I posted, and forgot to update
the Subject).

Here's what I do as the first line of each sub that saves/restores the settings
for the form:
If System.Reflection.Assembly.GetEntryAssembly Is Nothing Then Exit Sub

So, when inheriting from the base form, if we are in the designer, then I don't
restore or save the top, left, widht, height, maximized state of the form, only
when there is an EntryAssembly, which I'm assuming = an app that is running and
calling the code that way, not via a designer.

Matt
 
Matt,

I've run into similar problems in the form designer myself. Unfortunately,
it's very hard to debug. All I can recommend is comment everything out, and
brining it back in line by line.

-- Alex Papadimoulis
 
Alex Papadimoulis said:
Matt,

I've run into similar problems in the form designer myself. Unfortunately,
it's very hard to debug. All I can recommend is comment everything out, and
brining it back in line by line.
Click to expand...

Great advice -- luckily, though, since I'm so new and don't have a lot of code,
I eventually remembered that I DID change some code (namely added code that
referenced the EntryAssembly) that was causing the problem.

Thanks for the tip!

Matt
 
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