Why my application requires .NET 3.5 and .NET 4.0 Framework??

[Pete OHanlon]

That's exactly what I'm saying. While it has all the functionality, some of that functionality was moved between DLLs. Remember that the DLLs also have security in them to prevent them being tampered with, so each new version of the DLL gets a new security ID.

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[Roger Wright]

I'm not criticizing the .Net 4 distro, but it still leaves Lydia hanging - she needs stuff in 3.5 that was left out of 4, apparently. As much as I dislike Microsoft's way of doing business, they have been really good about including all the dependencies in previous rewrites, and it seems that they didn't do so this time. Of course, I'm relying on adubious source[^] and could be entirely confused.

Will Rogers never met me.

[Pete OHanlon]

Take a look at the criticism section which show that Microsoft were damned if they did and damned if they didn't: "Some developers have expressed concerns about the large size of the .NET Framework runtime installers for end-users. The size is around 54 MB for .NET 3.0, 197 MB for .NET 3.5, and 250 MB for .NET 3.5 SP1 (while using web installer the typical download for Windows XP is around 50 MB, for Windows Vista - 20 MB). The size issue is partially solved with .NET 4 installer (x86 + x64) being 54 MB and not embedding full runtime installation packages for previous versions." Basically, the issue they are addressing here is the user experience when somebody has to download code written for .NET 3.5 SP1 which resulted in a whopping 250MB download. What it sounds to me is Lydia has code that is still using a .NET 3.5 reference (in VS2010 you have the option just to choose .NET 4 references). The fix could be as simple as removing the reference to the old DLL and adding in the appropriate .NET 4 version. With .NET 4, it's not a good idea to mix with previous versions.

Forgive your enemies - it messes with their heads

My blog | My articles | MoXAML PowerToys | Mole 2010 - debugging made easier - my favourite utility

[Pete OHanlon]

As I explain to Roger below, you may just need to change the reference from a .NET 3.5 DLL to a .NET 4 DLL to get it working OK.

Forgive your enemies - it messes with their heads

My blog | My articles | MoXAML PowerToys | Mole 2010 - debugging made easier - my favourite utility

[Roger Wright]

Pete O'Hanlon wrote:

The fix could be as simple as removing the reference to the old DLL and adding in the appropriate .NET 4 version.

Good point; removing functionality that is dependent on a previous version and replacing it with more current versions might remove a lot of challenges.

Will Rogers never met me.

[lydiae]

Thanks for your replies and useful tips Roger and Pete!

[Pete OHanlon]

You are welcome, and good luck.

Forgive your enemies - it messes with their heads

My blog | My articles | MoXAML PowerToys | Mole 2010 - debugging made easier - my favourite utility

[Roger Wright]

You're quite welcome! :)

Will Rogers never met me.

[Jason Christian]

Actually, if you are compiling against .NET 3.5 so that your code works with 3.5 AND 4.0, then the issue is likely that you are using server-side components. .NET 4.0 is broken up into a Client Profile and Extended versions. .NET 4.0 by default only installs the Client Framework when installed on a client machine. Server-side (defined by Microsoft) components are not included (to keep the install size down). You can install them with the .NET 4.0 EXTENDED Framework, after which I would expect your service to work. If you set your compile target to .NET 4.0 Client Profile, you can discover which components are missing (because they are only in extended in 4.0), and possibly remove them if you want it to work with the 4.0 Client Profile.

[James Lonero]

Since your application is compiled for both .NET 3.5 and 4.0, you will need both installed. If you want to run on a system that only has 4.0 installed, you will need to recompile all of your projects (of the service or application) using .NET 4.0. Look at all of the responses for more ideas.