Could not load file or assembly 'System.Text.Json

[francois.lozes]

Anyone came across an error of this kind (and has an idea on how to fix it):

    Could not load file or assembly 'System.Text.Json, Version=5.0.0.0, Culture=neutral,   PublicKeyToken=cc7b13ffcd2ddd51' or one of its dependencies. The system cannot find the file specified.

It seems like Revit is trying to look for a version of System.Text.Json that is different from the one in the DLL I'm distributing with my adding (v5.0.2).

This kind of error appeared after updating my socketio-client to v3 which has by default System.Text.Json as a dependency instead of Newtonsoft.Json.

[jeremy_tammik · Accepted solution]

Check whether Revit itself is already loading the version you need, or, God forbid, a different one.

You can control which version you load yourself and where from by implementing an appropriate assembly resolver:

https://thebuildingcoder.typepad.com/blog/2014/05/rvtva3c-assembly-resolver.html

More examples of using this technique:

• Security, Framing Cross Section Analyser and REX
• Three.js AEC Viewer Progress on Two Fronts
• Keyboard Shortcuts and Other News
• State of the View and Data API, vA3C and Edge Ids
• Framing Cross Section Analyser and REX in Revit 2015   ^
• Support DLL, Zero Doc State and Forge Accelerators

Good luck, and beware of DLL hell. Here are some other discussions on resolving DLL conflicts:

• Handling Third Party Library DLL Conflicts
• Set Floor Level and Use IPC for Disentanglement
• RevitLookup Update, Fuslogvw and Override Joins
• Collaboration, Dockables, Railings, Pop-Ups, ILSpy

[francois.lozes · Accepted solution]

Thanks a lot Jeremy, just for potential future visitors I solved my issue with:

Assembly OnResolveAssembly(object sender, ResolveEventArgs args)
{
  string directoryDLLs = Path.GetDirectoryName(Assembly.GetExecutingAssembly().Location);

  // Fix for "Could not load file or assembly 'System.Text.Json" (maybe conflict with Revit)
  if (args.Name.Contains("System.Text.Json"))
  {
    string pathJson = Path.Combine(directoryDLLs, "System.Text.Json.dll");
    return Assembly.LoadFrom(pathJson);
  }

  // other assemblies

  string pathAssembly = Path.Combine(directoryDLLs, args.Name);
  if (File.Exists(pathAssembly))
  {
    return Assembly.LoadFrom(pathAssembly);
  }

  // assembly cannot be resolved
  return null;
  }

public Result OnStartup(UIControlledApplication application)
{

  // attach load assembly event handler
  AppDomain currentDomain = AppDomain.CurrentDomain;
  currentDomain.AssemblyResolve += OnResolveAssembly;

[Mr.CSurvey]

I'm having this same issue but I don't know anything about adding code to where its needed. Can you explain how I would go about adding the code?