After installing the ASP.NET MVC 4 Developer Preview, I can no longer open MVC 3 projects, with the following error message:
The project type is not supported by this installation.
<ProjectTypeGuids> in my MVC 3 .csproj file looks right:
<ProjectTypeGuids>{E53F8FEA-EAE0-44A6-8774-FFD645390401};{349c5851-65df-11da-9384-00065b846f21};{fae04ec0-301f-11d3-bf4b-00c04f79efbc}</ProjectTypeGuids>
Is this a bug in the MVC 4 developer preview, or is something missing from my Visual Studio 2010 install? And how do I solve it? Should I rollback my MVC 4 install?
I have tried running devenv /ResetSkipPkgs and installed MVC 3 Tools Update, to no avail.
"" If you want to update your projects to MVC4, and open them as such in the visual studio, then ""
The solution is to change the projectType guids from
{E53F8FEA-EAE0-44A6-8774-FFD645390401}
to
{E3E379DF-F4C6-4180-9B81-6769533ABE47}
in the csproj file, after you install the mvc4 visual studio package.
ASP.NET MVC 4 Developer Preview runs side by side with previous versions of ASP.NET MVC, however there are a few known issues to be aware of. The biggest one:
Installing ASP.NET MVC 4 Developer Preview breaks ASP.NET MVC 3 RTM
applications. ASP.NET MVC 3 applications that were created with the
RTM release (not with the ASP.NET MVC 3 Tools Update release) require
the following changes in order to work side-by-side with ASP.NET MVC 4
Developer Preview. Building the project without making these updates
results in compilation errors.
You'll find the solutions here.
I was searching for a different issue and stumbled across this question, It is similar to a few I answered and figured I would post them here:
ModelClientValidationRule conflict
Build Errors - 'System.Web.Mvc.ModelClientValidationRule' Conflicts
Check the reference to System.Web.Mvc.dll file in your reference. Make sure its pointing to C:\Program Files (x86)\Microsoft ASP.NET\ASP.NET MVC 3\Assemblies\System.Web.Mvc.dll
If its pointing to the one under ASP.NET MVC 4 directory then open your project file in a notepad. Look for
<Reference Include="System.Web.Mvc">
<Private>False</Private>
</Reference>
This should be changed to
<Reference Include="System.Web.Mvc, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35, processorArchitecture=MSIL" />
