Problem downgrading from C# 2010 to 2008

Question

For some reason, I have to move a lot of C# code from Visual Studio 2010 to Visual Studio 2008.

I edited my sln file to reflect the changes

Microsoft Visual Studio Solution File, Format Version 11.00

to

Microsoft Visual Studio Solution File, Format Version 10.00

It allowed the solution to be loaded into VS2008. Afterwards I edited every csproj to target the Framework .NET 3.5

This allowed the projects to compile

I can run it in Release mode "correctly" (with some bugs due to modifications from .NET 4.0 specifics to 3.5 equivalent)

Now I got the following error message in debug mode

My google fu revealed that I could screw up the registry while searching for "The application you are trying to debug uses a version". It pointed me to this page

I'm pretty sure there is an error on this page where it refers to 8.0 for both 2005 and 2008 help pages. So I did that, I created the registry key CLRVersionForDebugging with value "v3.5" just like the directory in C:\Windows\Microsoft.NET\Framework shows

Now I get the following message :

I can't find relevant information to solve this problem. This is a huge pain. I don't want to recreate the projects manualy, there are hundred of source/configuration files. Any help would be greatly appreciated.

Here is an example of a project file which will not debug

<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="3.5" DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003"&gt;
  <PropertyGroup>
    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
    <Platform Condition=" '$(Platform)' == '' ">x86</Platform>
    <ProductVersion>9.0.21022</ProductVersion>
    <SchemaVersion>2.0</SchemaVersion>
    <ProjectGuid>{61547F81-8F73-4E38-ACDB-B51253A90EBC}</ProjectGuid>
    <OutputType>WinExe</OutputType>
    <AppDesignerFolder>Properties</AppDesignerFolder>
    <RootNamespace>FlowchartEditor</RootNamespace>
    <AssemblyName>FlowchartEditor</AssemblyName>
    <TargetFrameworkVersion>v3.5</TargetFrameworkVersion>
    <TargetFrameworkProfile>
    </TargetFrameworkProfile>
    <FileAlignment>512</FileAlignment>
  </PropertyGroup>
  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|x86' ">
    <PlatformTarget>x86</PlatformTarget>
    <DebugSymbols>true</DebugSymbols>
    <DebugType>full</DebugType>
    <Optimize>false</Optimize>
    <OutputPath>bin\Debug\</OutputPath>
    <DefineConstants>DEBUG;TRACE</DefineConstants>
    <ErrorReport>prompt</ErrorReport>
    <WarningLevel>4</WarningLevel>
  </PropertyGroup>
  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|x86' ">
    <PlatformTarget>x86</PlatformTarget>
    <DebugType>pdbonly</DebugType>
    <Optimize>true</Optimize>
    <OutputPath>bin\Release\</OutputPath>
    <DefineConstants>TRACE</DefineConstants>
    <ErrorReport>prompt</ErrorReport>
    <WarningLevel>4</WarningLevel>
  </PropertyGroup>
  <ItemGroup>
    <Reference Include="System" />
    <Reference Include="System.Core">
      <RequiredTargetFramework>3.5</RequiredTargetFramework>
    </Reference>
    <Reference Include="System.Xml.Linq" />
    <Reference Include="System.Data.DataSetExtensions" />
    <Reference Include="System.Data" />
    <Reference Include="System.Deployment" />
    <Reference Include="System.Drawing" />
    <Reference Include="System.Windows.Forms" />
    <Reference Include="System.Xml" />
  </ItemGroup>
  <ItemGroup>
    <Compile Include="Editor.cs">
      <SubType>Form</SubType>
    </Compile>
    <Compile Include="Editor.Designer.cs">
      <DependentUpon>Editor.cs</DependentUpon>
    </Compile>
    <Compile Include="EditorMDI.cs">
      <SubType>Form</SubType>
    </Compile>
    <Compile Include="EditorMDI.Designer.cs">
      <DependentUpon>EditorMDI.cs</DependentUpon>
    </Compile>
    <Compile Include="OutputSignalSelect.cs">
      <SubType>Form</SubType>
    </Compile>
    <Compile Include="OutputSignalSelect.Designer.cs">
      <DependentUpon>OutputSignalSelect.cs</DependentUpon>
    </Compile>
    <Compile Include="Program.cs" />
    <Compile Include="PropertiesEditor.cs">
      <SubType>Form</SubType>
    </Compile>
    <Compile Include="PropertiesEditorDisplayUnit.cs" />
    <Compile Include="Properties\AssemblyInfo.cs" />
    <Compile Include="ToolboxForm.cs">
      <SubType>Form</SubType>
    </Compile>
    <Compile Include="ToolboxForm.Designer.cs">
      <DependentUpon>ToolboxForm.cs</DependentUpon>
    </Compile>
    <EmbeddedResource Include="Editor.resx">
      <DependentUpon>Editor.cs</DependentUpon>
      <SubType>Designer</SubType>
    </EmbeddedResource>
    <EmbeddedResource Include="EditorMDI.resx">
      <DependentUpon>EditorMDI.cs</DependentUpon>
      <SubType>Designer</SubType>
    </EmbeddedResource>
    <EmbeddedResource Include="OutputSignalSelect.resx">
      <DependentUpon>OutputSignalSelect.cs</DependentUpon>
      <SubType>Designer</SubType>
    </EmbeddedResource>
    <EmbeddedResource Include="PropertiesEditor.resx">
      <DependentUpon>PropertiesEditor.cs</DependentUpon>
      <SubType>Designer</SubType>
    </EmbeddedResource>
    <EmbeddedResource Include="Properties\Resources.resx">
      <Generator>ResXFileCodeGenerator</Generator>
      <LastGenOutput>Resources.Designer.cs</LastGenOutput>
      <SubType>Designer</SubType>
    </EmbeddedResource>
    <Compile Include="Properties\Resources.Designer.cs">
      <AutoGen>True</AutoGen>
      <DependentUpon>Resources.resx</DependentUpon>
      <DesignTime>True</DesignTime>
    </Compile>
    <EmbeddedResource Include="ToolboxForm.resx">
      <DependentUpon>ToolboxForm.cs</DependentUpon>
      <SubType>Designer</SubType>
    </EmbeddedResource>
    <None Include="app.config" />
    <None Include="Properties\Settings.settings">
      <Generator>SettingsSingleFileGenerator</Generator>
      <LastGenOutput>Settings.Designer.cs</LastGenOutput>
    </None>
    <Compile Include="Properties\Settings.Designer.cs">
      <AutoGen>True</AutoGen>
      <DependentUpon>Settings.settings</DependentUpon>
      <DesignTimeSharedInput>True</DesignTimeSharedInput>
    </Compile>
  </ItemGroup>
  <ItemGroup>
    <ProjectReference Include="..\flowchart\flowchart\flowchart\flowchart.csproj">
      <Project>{4E7DDA00-651D-4CC0-833C-83E60ADE552B}</Project>
      <Name>flowchart</Name>
    </ProjectReference>
    <ProjectReference Include="..\PluginMiddleMan\PluginMiddleMan.csproj">
      <Project>{CDACB6A0-6DEC-48B6-B3B1-628968B50F5C}</Project>
      <Name>PluginMiddleMan</Name>
    </ProjectReference>
    <ProjectReference Include="..\ToolBox\ToolBox.csproj">
      <Project>{D937E1F4-1B9F-4567-B28E-EED24AA31C9C}</Project>
      <Name>ToolBox</Name>
    </ProjectReference>
    <ProjectReference Include="..\WinFormsUI\WinFormsUI.csproj">
      <Project>{C75532C4-765B-418E-B09B-46D36B2ABDB1}</Project>
      <Name>WinFormsUI</Name>
    </ProjectReference>
  </ItemGroup>
  <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
  <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
       Other similar extension points exist, see Microsoft.Common.targets.
  <Target Name="BeforeBuild">
  </Target>
  <Target Name="AfterBuild">
  </Target>
  -->
</Project>

Answer 1

Have you changed the "ToolsVersion" at the tol of the .csproj files? It may be useful to post an example of one of the project files.

Answer 2

On my VS 2008 SP1 install, I have both AD7Metrics and AD7Metrics(Debug) keys under HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\VisualStudio\9.0. AD7Metrics indeed contains {449EC4CC-30D2-4032-9256-EE18EB41B62B}. AD7Metrics(Debug) does not.

Try creating the {449EC4CC-30D2-4032-9256-EE18EB41B62B} subkey and its CLRVersionForDebugging value under AD7Metrics(Debug).

Answer 3

Do you get this same problem if you start a new test project in VS2008 and debug? If not, then maybe you would be better off creating new csproj files and dragging your existing code files into the new project.

Personally, if your visual studio installation is stable (othe r2008 projects build ok), I would rather go that route that to go mucking with global state in your registry.

Answer 4

Check the contents of the app.config file in your project. It might contain <requiredRuntime> or <supportedRuntime> elements targeting .NET 4, which probably would confuse the debugger.

EDIT: Get rid of the CLRVersionForDebugging values for the time being. The goal is to reproduce the first error message (I have a bad feeling about the second one...)