Retargeting All Projects in a Solution to .NET 4.5.2

I have a solution in Visual Studio 2012 with 170 C# projects in it. I need to retarget all of the projects from .NET Framework 4.0 to 4.5.2.

I prefer to let Visual Studio handle this by going into the properties of each project, changing the targeted framework, and letting Visual Studio make any necessary changes to the .csproj files.

I noticed that these changes include adding a few new XML tags to the .csproj, depending on some attributes of the current project.

How can I batch retarget all 170 C# projects without just using a replace text tool to replace the targeted version number? I want Visual Studio to make all the necessary tag modifications and additions and replace alone will not permit that to happen.

The MSDN documentation "Migration Guide to the .NET Framework 4.5" and "How to Configure an App to Support .NET Framework 4 or 4.5" only discusses modifying projects. There's no details on applying changes to the entire solution at once, nor have I seen a function in VS that supports it.

However, there's a (well-rated) extension called Target Framework Migrator available in the Visual Studio gallery, which supports upgrading to 4.5.2 (as well as newer versions**) and looks like it'll do exactly what you want. The source code is available on GitHub, if you're interested.

Note that the lack of such a feature may be intentional (and not just an omission). I'm just guessing, but maybe MS figures only projects that need the new Frameworks will be upgraded. FWIW, if you end up upgrading some projects that are shared with other solutions, those solutions may fail to build until they're upgraded too.

That being said, if you're in a small shop with just one (or a few) solutions and you're looking to upgrade everything in one go, then perhaps the above tool will work for you.

---

> There's been no development on this for years, and apparently the developer has no plans to pass the baton to anyone else.

If you're unable to get it to work with a newer .NET Framework version, check the existing PRs and Issues for fixes, but you may have to apply them yourself. For example, someone posted a fix for .NET Framework v 4.7.1. Hopefully these will get merged, but I wouldn't hold my breath.

If anyone else is seeing the same error as Anas (in the comments), here's a GitHub issue from a couple weeks ago, and another possibly related issue from 2017. Consider thumbs upping them and adding more details if you're having the same problem.

For a .NET Framework solution, a simple "Replace in files" did the trick for me:

eg: From .NET Framework 4.5.2 to .NET Framework 4.7.2

In package.config files, replace all

targetFramework="net452" 

to

targetFramework="net472" 

In *.csproj files, replace all

<TargetFrameworkVersion>v4.5.2</TargetFrameworkVersion> 

to

<TargetFrameworkVersion>v4.7.2</TargetFrameworkVersion>

Since the Target Framework Migrator is broken, I rolled my own search/replace (using git bash, it works ok on windows) ; Basically it changes the v4.6.x into v4.7.2, then it converts back the files to using the infamous DOS's CRLF :

find . \( -iname '*.csproj' -o -iname '*.vcxproj' -o -iname 'app.config' \) \
 -exec grep -Z -l 'v4\.6\..' \{} \; | xargs -0 sed -i 's/v4\.6\../v4.7.2/'  
find . \( -iname '*.csproj' -o -iname '*.vcxproj' -o -iname 'app.config' \) \
 -exec grep -Z -l 'v4\.7\..' \{} \; | xargs -0 unix2dos

I have built myself a simple tool to migrate the target framework versions for an entire solution, because the Target Framework Migrator Extension does not support Visual Studio 2017. Download the tool from my GitHub repository https://github.com/Xpitfire/TargetFrameworkMigrator

I know this is not the best way to go, but it worked for me and maybe it will also help someone else.

Target Framework Migrator is pretty useful. By default, it comes up to v4.7. However, it's easy to add support for v4.7.1, v4.7.2 and v4.8.

Find Frameworks.xml file in C:\Users{username}\AppData\Local\Microsoft\VisualStudio\ folder and edit by adding these framework versions:

<Framework Id="262152" Name=".NETFramework,Version=v4.8"/>
<Framework Id="262663" Name=".NETFramework,Version=v4.7.2"/>
<Framework Id="262407" Name=".NETFramework,Version=v4.7.1"/>

After you restart visual studio, you will see new versions.

public void ChangeFramework() {

  //Add Reference to envdte (Assemblies\Extensions\envDTE)
  string SolutionFile = @"C:\MyProject\MyProject.sln";
  string ProjectName = "MyProject";

  //------------------------------------------------------------------------
  //Find the Program ID from the registry for VisualStudio.DTE
  //Look it up In Registry: Computer\HKEY_LOCAL_MACHINE\SOFTWARE\Classes
  System.Type oType = System.Type.GetTypeFromProgID("VisualStudio.DTE", true);
  EnvDTE.DTE dte = (EnvDTE.DTE)Activator.CreateInstance(oType, true);

  //------------------------------------------------------------------------
  //Open your Solution
  dte.Solution.Open(SolutionFile);

  //------------------------------------------------------------------------
  //Now In your solution go through what is listed in dte.Solution.Projects 
  //and find the one that match what you want to change target for
  int iItemsCount = dte.Solution.Projects.Count;
  string sCurrent = "";

  for (int i = 1; i <= iItemsCount; i++) {

    sCurrent = dte.Solution.Projects.Item(i).Name;

    if (dte.Solution.Projects.Item(i).Name == ProjectName) {
      //Once you find your project, Change the Framework
      EnvDTE.Project oProject = dte.Solution.Projects.Item(i);
      oProject.Properties.Item("TargetFrameworkMoniker").Value = ".NETFramework,Version = v4.6.2";
    }
  }

  //------------------------------------------------------------------------
  //Close your Solution
  dte.Solution.Close();
}