[triangulator]

I've been developing a program with VS2010 and .NET framework 4 client profile.
However, windows 7 (and AFAIK windows xp, correct me if I'm wrong) is distributed with .NET framework 3.5 SP1.
I want users to be able to use my program if, for some reason, they don't want to, or more likely can't(e.g. no connection to internet or not knowing well English), install the newer version of .NET framework.
Upon changing the target framework of my project to a lower version I'm being warned that this may require a manual modification of it. My question is - what does that include? Will I simply get a list of errors of things not present in the earlier version that I need to fix? Will I have to manually change some functions, may be if they don't exist, etc? Or what?
Is it okay to switch back and forth between the target frameworks while developing my project? Or should I rather create an entirely different one for .net 3.5?
Also, what is the difference between '.NET Framework 3.5' and '.NET Framework 3.5 Client profile' and also '.NET Framework 4' and '.NET Framework 4 Client profile' respectively?
Thanks in advance.

[modi123_1]

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Upon changing the target framework of my project to a lower version I'm being warned that this may require a manual modification of it. My question is - what does that include? Will I simply get a list of errors of things not present in the earlier version that I need to fix?

Yes, maybe.

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Will I have to manually change some functions, may be if they don't exist, etc?

Maybe.. I don't know what or how your code was developed.

Try this - close out of VS.
Copy your solution to a new folder..
Go into that copied solution and try to convert it. See what happens. It's a copy - so no harm or foul try trying, right?

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Is it okay to switch back and forth between the target frameworks while developing my project?

I prefer shooting for one and going with it.

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Or should I rather create an entirely different one for .net 3.5?

That seems to be an awful amount of work when the tool to convert is right there.

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Also, what is the difference between '.NET Framework 3.5' and '.NET Framework 3.5 Client profile' and also '.NET Framework 4' and '.NET Framework 4 Client profile' respectively?

[quote]The .NET Framework 4 and earlier versions provided two deployment options: the full .NET Framework and the Client Profile, which was a subset of the .NET Framework that was optimized for client applications.
http://msdn.microsof...y/cc656912.aspx

[triangulator]

Thanks, that is good to know. So when I copy the project, change the target framework to 3.5 and remove all the errors the IDE shows, after compiling the program won't crash or throw error messages randomly because of some hidden consequences (and incompabilities) of migrating to an earlier version?
However the above question sounds, it is serious, as I'm complete newbie when it comes to compability issues between .net versions (and almost complete to .net). I simply want to make sure that users won't experience such unpleasanties.

[modi123_1]

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Thanks, that is good to know. So when I copy the project, change the target framework to 3.5 and remove all the errors the IDE shows, after compiling the program won't crash or throw error messages randomly because of some hidden consequences (and incompabilities) of migrating to an earlier version?

In theory no, but again stranger things have been coded up that fly in the face of that. The gist is newer versions of .NET subsume previous verions. If you are calling something that is 4.0 specific VS will let you know.

Of course all of this could be solved by including an install for 4.0 with your app, right?

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However the above question sounds, it is serious, as I'm complete newbie when it comes to compability issues between .net versions (and almost complete to .net). I simply want to make sure that users won't experience such unpleasanties.

Aaaaaaaaaand that's why the good lord provided time for testing. Regression or otherwise.

[triangulator]

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Of course all of this could be solved by including an install for 4.0 with your app, right?

It by no doubt could. I didn't know I can do that, where can I read more about how to do this?

[modi123_1]

VS -> new project -> other project types -> setup and deployment

Screen shots I didn't want to do can be found here:
http://stackoverflow...e-net-framework

[triangulator]

Sorry for the bump, but how can I do this installer if I only have the express version?

[modi123_1]

Show me a screen shot of what options you have.

[triangulator]

I searched in the online templates, but didn't find the necessary one.

[modi123_1]

If you can't find the template then you are more or less SOL. Upgrade to a paid version. ... or make your own template.

[h4nnib4l]

Make sure you check through your references, too. I wrote a couple of .DLLs to be included as COM objects for a classic ASP app a while back, and (absent-mindedly) wrote them targeting .NET 4.0 instead of 2.0. Now this was obviously a much bigger fundamental jump than the one you're talking about making, but I lost access to a lot of the assemblies I had used. Among other things, a massive chunk of code that I had written as extension methods had to be updated because support for extension methods wasn't around back then. Again, this was a much bigger jump, but you might still find some things that you've used that weren't a part of .NET at version 3.5, so just be aware of that issue.

[Curtis Rutland]

Well, there's also ClickOnce deployment, you can do this with any version of VS. This publishes your application, and you can publish it to a web path, or a file share, or a CD/DVD. If it's a web or file share path, the application will "phone home" to look for updates, and it'll handle framework dependencies automatically when the user tries to install.

Otherwise, there are a few other options out there that I haven't used. Nullsoft installer (free, I think), InstallShield (not free), etc.

[h4nnib4l]

+1 to ClickOnce. I love the fact that changes, whether major or minor, can be implemented simply by building, incrementing a version number, and clicking publish.

[modi123_1]

Click once is okay... of course users ruin the fun of it occasionally... and it's a bit rough when you need to distro cds or usb drives to install. Over all - nice in the home office!

[Skydiver]

But will ClickOnce recognize that your target machine doesn't have the .NET framework, or the appropriate version of the .NET framework and take you through the needed steps to get it installed? I was under the impression that ClickOnce only works if the framework is already installed on the target machine.