Hi!

Most often designer problems come when you use own controls that do not respect DesignMode property. For example, you may have some control that issue some resource read or static class access operations that may not be valid at design time.

Another reason why designer can't load is syntax error in source, but this is easy to see and fix.

Welcome to hell.

The designer spins up an instance of your form using only *some* of your code. I reported this as a bug, but it's apparently 'by design'. What it means is, you need to code VERY defensively in your forms. Consider which events you've created that will fire when the form is shown by the designer. Consider all your member variables, do you always check if they are a value you expect before using them ? One example that took me a while to pick - I had a form with a bitmap on it. I assumed in my code it was a particular bit depth. My code just checked if the bitmap was null, otherwise, I assumed my bitmap creating code had made a bitmap of the right bit depth. The designer was stuffing a bitmap of PixelFormat.Undetermined into that property, which I didn't even know existed, and gave me one of the exact sort of errors you describe ( from memory, that was the one that plain crashed the IDE every time I tried to open design view )

Moving from a VS2003 project is a nightmare because of these issues, but the good news is, once you understand the cause and fix the ones you have, you'll find it pretty much second nature to code in a way that stops it happening any more. And I will (grudgingly ) accept that my code is theoretically better for the changes I am making, even if none of them would make a spot of difference in the real world.

I have to admit, I really understand what you're saying. I went through it. However, I also found that sometimes my form opened and sometimes it would not. Specifically, if I opened the form for the first time, it would work, if I browsed away to code and came back, it would crash. I suspect the code in InitializeComponent, which gets updated every time, was the reason for this.

// I'm really thinking the VS2005 designer is just poorly designed.

I tend to agree, but the official position is that it's become less forgiving as a feature, so we clean up our code :-)

The IDE does show you in the error list where it's having the trouble, you might want to look there. I doubt that recreating your project will help. Perhaps creating a copy and removing controls one at a time to see which one causes the crash is a reasonable approach to take.

*grin* I assumed you were experienced, mostly because this problem only happens when migrating projects, so you obviously have been coding in VS2003, at least :-)

Today I find another way to break form designer, nothing special, just playing with two DataGridViews, no hand coding and no custom controls. Lucky me I find the way to manually fix problem later in source code. Yes, forms designer is stuff thatisn't stabilized well.

What controls do you have in your form? Standard only or custom too? Do you use controls that may autogenerate stuff, like DataGridView, that generate columns (arrghhh!) when I set DataSource (and I already made necessary columns by hands).

All designer problems comes from fact that it create form's base class(Form typically) and place in it all controls, that compiled in temporary assembly. Due this fact it's really good to code controls with less coupling, i.e. they must reference other types as less as possible.

Another reason of yourtrouble (which is really bigger than mine - my VS crashes rarely) - you may have beta version. It's theoretical, but possible.

And one (my favorite ) problem with VS is that it use caching here and there. I know that toolbox caching are not stable yet and even reinstalling VS may not help (uninstall leave cache as is). Probably there is some designers caches or other caching took place? Hard to help here, but at least you can try empty Temp folder, shouldn't hurt.

Anyway you better report this bug here http://lab.msdn.microsoft.com/productfeedback/default.aspx, so MS will take care & fix it.

"Path is not of a legal Form".

We have gotten customer feedback on this error reported here:

http://lab.msdn.microsoft.com/ProductFeedback/viewFeedback.aspx?feedbackid=3d84fe85-d2c1-43b0-9724-6fd641506456

The only cause that we have been able to determine is that one of the references in the project is invalid (doesn't point to anything). This causes an exception when the designer attempts to load. There may be other causes and if you can describe a repro (shorthand for "reproduce the error"), please reactivate the product feedback issue or create a new one.

To fix this issue, ensure that all of your references do not have yellow warnings and are properly resolved (click on thier properties and see that each points to an assembly with some path).

"Could not load file or Assembly"

This may happen if you do not have that assembly referenced in your project. If you are sure you do -- then this could be a product bug and I urge you to use the product feedback site to create a bug on it.

In your particular callstack, it looks like the Type is being used either as a Property type or an attribute on a property.

We know that this White Screen of Darn is really annoying. We are looking at addressing this by both increasing the helpfulness of the error messages and eliminating any product bugs that may make this more frequent.

We do need this error screen to stop any further work on the designer because if we ignored errors (as we did in VS2003), then it may cause data loss.

So, I would urge anyone who is encountering frequent issues like this to use the product feedback site. We will be enumerating all occurrences for message "helpfulness" and we will be fixing product issues that cause it.