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Application runtime compatibility - Visual studio.NET 2003, 2005 & .NET Framework 1.1, 2.0

With the release of .Net 2.0 and VS.NET 2005 there are lot of questions on compatibility and co-existence between the different runtimes and applications that utilize them. The following pointers may be helpful in understanding those.( Terminology - VS -> Visual Studio, .NET FW -> .NET Framework)

           
1. Multiple versions of .NET and Visual Studio.NET *can* peacefully co-exist in a machine as long as they were installed in the chronological order (7.0, 7.1 and 8). Importantly, a solution created in a older version of VS.NET will open up with that version only when you double click the solution file( File->Open doesn’t do this – the solution will be opened in the current VS if possible). Be warned, .NET framework versions and VS.NET are hardbound to each other. The following pairs are hardbound to each other
a. VS.NET 2003 & .NET FW 1.1
b. VS.NET 2005 & .NET FW 2.0
This means using VS.NET 2003 you can target only .NET FW 1.1 framework applications only. Also, VS.NET 2005 cannot target the .NET FW 1.1 framework. (Why so? https://blogs.msdn.com/johnri/archive/2005/11/29/498219.aspx will tell you...)

2. However applications can be ‘run’ under a .NET FW runtime different from the one they were compiled with. For ex, an application written using VS.NET 2003 can be ‘run’ under the 2.0 runtime. VS.Net 2005 applications cannot run under the pre – 2.0 runtime but they should be theoretically able to run under all the future versions of .NET runtime unless the application uses some stuff thats part of the breaking changes. This can be achieved using the config file approach explained in the next point.(Read more about compatibility and breaking changes at https://www.gotdotnet.com/team/changeinfo/default.aspx). To get the official word from MSDN use https://msdn.microsoft.com/netframework/default.aspx?pull=/library/en-us/dnnetdep/html/netfxcompat.asp. This can be achieved using the config file approach explained in the next point.

3. The .NET framework runtime is actually a set of dlls – this means there can only be one set of these dlls in a process. No matter what we do, we CANNOT have more than one runtime versions of .NET in a process. And, the first one to be loaded wins. If your process loads .NET V 1.0 first and if you attempt to load 1.1 or 2.0 subsequently they will all fail.

4. An unmanaged application can also use the .NET framework runtime by means of in-process runtime interaction with a managed component. By default all unmanaged applications load the latest available versions of the .NET runtime installed in the machine. This behavior can be changed by using a ‘config file’ and effecting the change.

a. Consider a machine that has both .NET FW 2.0 and 1.1 installed. Consider an unmanaged app um.exe that interacts with managed com components. By default, the um.exe will try to run under the 2.0 runtime only. If the managed component it loads comes from the 1.1 world, the app will have weird unexpected behaviors. It can throw up some error messages in the form of exceptions or some unexpected crash or a totally unfriendly error message. This will get in the way of debugging such an application using Visual Studio as well. To ensure this app always uses .NET 1.1 a config file called um.exe.config( in the same folder as um.exe )should be created and that file will have the following contents
<?xml version ="1.0"?>
<configuration>
<startup>
<supportedRuntime version="v1.1.4322" />
</startup>
</configuration>

The MSDN link that talks about this - https://msdn2.microsoft.com/en-us/library/9w519wzk.aspx

b. The CorBindToRuntimeEx - https://msdn2.microsoft.com/en-us/library/99sz37yh.aspx can be used to ‘hard bind’ an unmanaged application to a .NET framework runtime. This function does much more that enabling this. Read the API reference before you decide to use this approach.

c. When compiling your unmanaged application set the /clr flag using the properties dialog. This will make your application as ‘managed’ and will always load the runtime that came with the VS.NET you are compiling this app in. This technique is ‘c’ – only if you don’t want a & b.

5. Assembly redirection – It is possible to have one reference to a .NET Framework version 1.1 assembly and another reference to a .NET Framework version 2.0 assembly, you would use the pattern shown in the following pseudocode

<assemblyBinding xmlns="..." appliesTo="v1.1.4322">
<! — .NET Framework version 1.1 redirects here. -->
</assemblyBinding>

<assemblyBinding xmlns="...">
<!-- Redirects meant for all versions of the .NET Framework. -->
</assemblyBinding>

Having these entries in the machine.config file will let you use the redirected assembly whenever the original assembly is specified. However, this doesn’t mean that you are using 2 different runtimes. This technique will work after a runtime has been loaded. So this is *not* a way to load a different runtime.
For more information on assembly redirection - https://msdn2.microsoft.com/en-us/library/433ysdt1.aspx

Do let me know if you have any questions.

Note : Thanks to Ravi Uppaluru, Manoj Mohunthan & Jaganathan Thangavelu for pointing out missing and vague items(duly corrected ;-) ) in the intial draft of this article.

[Edit history]
1. Feb 27, 2006 - added John Rivard's blogs entry explaining VS-.NET FW pairing. Thanks to Dat Bui for pointing this out.

2. Aug 18, 2006 - Some of the issues mentioned here are taken care by https://blogs.msdn.com/seshadripv/archive/2006/06/09/623871.aspx

Comments

  • Anonymous
    February 24, 2006
    A good blog post from way back, about not forcing an app you don't 'own' to one version of the CLR:

    "We're all sharing the same process--let's play nice"

    http://blogs.msdn.com/eric_carter/archive/2004/04/30/123984.aspx

  • Anonymous
    March 22, 2006
    is there any way to run a dll that was created in VS 2005 2.0 in an application that was created in VS 2003 1.1?

  • Anonymous
    March 23, 2006
    Hi Dean,

    Yes - if you configure the 1.1 FX application to load under 2.0 and dynamically use the 2005 dll.

    If you can provide me with more details i can try to answer more precisely. Specifically on the type of interaction you intend between the exe and the dll.

    Seshadri

  • Anonymous
    June 14, 2006
    can i run application build with  framwork 1.1 in VS 2005 ??
    i dnt want to convert 1.1 to 2.0
    is it possible to run 1.1 application without convert to 2.0??

  • Anonymous
    June 14, 2006
    Hi Parimal,

    See if this helps - http://blogs.msdn.com/seshadripv/archive/2006/06/09/623871.aspx

  • Anonymous
    June 20, 2006
    how to configure the 1.1 FX application to load under 2.0 and dynamically use the 2005 dll?

  • Anonymous
    June 20, 2006
    Anees,
    use a config file like this for your V1.1 managed exe-
    <?xml version ="1.0"?>
    <configuration>
     <startup>
       <supportedRuntime version="v2.0.50727" />
     </startup>
    </configuration>

    This should do what you want

  • Anonymous
    June 21, 2006
    The comment has been removed

  • Anonymous
    June 23, 2006
    The comment has been removed

  • Anonymous
    June 25, 2006
    fine seshadripv,

    Thanks for your reply.

    In System.web.mail, we could not get the rejected recipient addresses. Then, we found that System.net.mail is providing SmtpFailedRecipientException to get the rejected recipient addresses...

    Is it possible to get the rejected recipient addresses from System.web.mail itself?

    Thanks in advance.

    Regards
    Anees

  • Anonymous
    June 26, 2006
    Anees,
    The namespace/class you have in question is not something i am familiar with. MSDN newsgroups would be a better place to answer that.

    thanks
    Seshadri

  • Anonymous
    June 26, 2006
    Seshadri,

    thanks for your reply and advice.

    Thanks
    Anees

  • Anonymous
    July 12, 2006
    I'm trying to implement the System.Web.UI.ICallbackEventHandler using VS 2003 however this is a VS 2005 feature.  Is it possible to use the MSDN 2005 library with VS 2003?

  • Anonymous
    July 16, 2006
    The comment has been removed

  • Anonymous
    August 17, 2006
    Very interesting. I think I have a related problem. I am programming in Visual Basic 2005 and will be running it with an API and assembly that are not compatible with 2005. The vendor states: "We have found a number of problems with the .NET 2.0 framework, and at this time we can only support use of 1.1 (.NET 2003)", "The API, however, does not work well with .NET 2005.", "we cannot support 2005 at this time because of the issues with .NET 2.0.  You should be fine using .NET 1.1. so you would need to use 2003 if you want to use the .NET languages." , "the issues are Primarily unexplained System Call Failures. You are welcome to try 2005, but know that we cannot provide support in that environment."
    Do you have any suggestions - I am using Backgroundworker and some of the new controls so don't want to switch back to 2003. What can I do?
    Thanks,
    Getchen




  • Anonymous
    August 17, 2006
    Hi Gretchen,

    Could you send me a mail directly with your current issue? i will respond to you directly and probably add a summary here in this space.

    In the meantime you may want to check this out - https://blogs.msdn.com/seshadripv/archive/2006/06/09/623871.aspx - 'PowerToys' lets you use VS 2005 with .NEt FW 1.1. However at runtime only one version of the CLR can be loaded.

  • Anonymous
    August 18, 2006
    Thanks for your prompt reply!
    Can't locate your email address? You can email it to me at gretchen@cmi.gccoxmail.com

  • Anonymous
    November 13, 2006
    Hi, I created a solution in VS .NET 2005. But i now want the solution to open and run under VS .NET 2003. How can this be possible???

  • Anonymous
    December 16, 2006
    There is no direct way to open VS2005 project in VS2003 . You can open new project in 2003 and cut and paste the code.

  • Anonymous
    January 02, 2007
    Great blog, thanks for the nice explanation..

  • Anonymous
    January 12, 2007
    I am trying to determine whether an object that I created in VS 2005 will be able to be referenced and called from a project in VS 2003.  Everything I have tried leads me to believe no, but I am not sure.  I want to avoid using the COM interop if I can help it.

  • Anonymous
    July 22, 2007
    I have .dlls made in Visual Studio 2003. I need to use these in a project being built using VS 2005. Is it possible, and if so, how do I add reference to these .dlls in VS 2005. Currently, my VS is not recognising these dlls, regsvr32 too isn't helping. Thanks.

  • Anonymous
    August 29, 2007
    Hi guys,       I am calling a managed dll build in 2.0 from a vb 6.0 application, the dll runs well under clr 2.0 but the vb application breaks.      I was previously using managed dll built with 1.1, and that was working fine. i have framework 1.1 and 2.0 installed with windows server 2003. can u guys tell me what could be the problem?? Thank You.

  • Anonymous
    April 02, 2008
    Hi Guys,             Is it possible to Create a sub virtual directory (V 1.1) under a Virtual Directory (which is in V 2.0). I created but it is not working. Can u  tell me what could be the problem? Thanks in Advance.