Problem in Add Reference dialog with paths containing #

I am new to using Microsoft development tools but have been using Visual Studio 2010, .NET 4 and C# for the past few weeks. I ran into a problem yesterday creating a new project the same way I have been doing it successfully from the start: right-click on the project in the Solution Explorer → Add Reference, which used to bring up this dialog:

Old Dialog Box http://img514.imageshack.us/img514/8978/oldaddreferencedialogue.jpg

After a couple of weeks of no new projects I went to create one yesterday and got a new Add Reference dialog. And trying to add the same dll I have been adding for weeks now resulted in the error seen here:

New Dialog http://img692.imageshack.us/img692/2074/newaddreferencedialogue.png

So, after a painful day trying to determine the cause, it looks to me like it has something to do with the new dialog choking on the # I had in my reference path. When I removed the # everything works as expected. Considering Microsoft has two .NET languages with # in the name, I am surprised that this issue keeps biting people (I have heard of this problem over the years, but I have never done much with Microsoft tools until recently, so of course I did not recall it.)

Questions from a Visual Studio newbie:

1. Is it common knowledge to not use # in paths?

2. How/why did I get this new Add Reference dialog when my colleagues, using the same VS version, still have the old dialog that handl开发者_Python百科es # in paths just fine?

My opinion is that if you use weird characters in paths, you get what you deserve. :)

I know there are bugs about '#' character in paths in the core VS product, in addition to whatever may be in the Pro Power Tools extension. There is a surprising amount of code that goes to/from URIs and filenames, and '#' characters (and everything thereafter) get dropped when roundtripping via a System.Uri.

In general, I think it's safe to assume that when creating filenames/paths, there will be 10,000 tools of various quality trying to parse the filenames, and a (large) subset of those tools will fail on 'weird' characters. Just avoid weird characters whenever possible. You gotta choose your battles. In an ideal world, tools would be robust to these kinds of issues. In the real world, it's better to name a path "CSharp" rather than "C#" and move on with more important things in life.

The second dialog is the one from the VS2010 productivity power tools pack - I havent used it myself so dont know of any problems with it. Have you recently installed this?