.NET 6 Activity System.Activities not found

I Try to make a super simple activity in .NET 6., using CodeActivity.
When I try to import the pckage to Studion it fails with the error: Could not load assembly System.Activities.dll.

I have tried a number of different ways to reference the UiPath workflow packages, and even tried to import the dll directly - all to no success.
In .csproj I have:

<PackageReference Include=UiPath.Workflow Version=6.0.3/>
<PackageReference Include=UiPath.Workflow.Runtime Version=6.0.3 >

The activity is a simple code activity:
public class TheStuff : CodeActivity {

I’ve tried to follow this but it does not seem up to date.
Migrating Activities to .NET 6 (uipath.com)

I have tried nuget pack with nuspec file, and dotnet pack on the project.

UiPath Studio 22.7 (and previous versions)
Visual Studio 2022

1 Like

Hello @Jesper_Rasmussen!

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Hi Rasmus,

I have exactly the same problem and have been struggling for quite a long time now.

There doesn’t seem to be any updated documentation of how to manage to create
a .Net6 activity.

Did you find a solution or if you do in the nearby future, I would very much appreciate if you post an update here.


I think you ment to reply to something else :wink:

Basically .net 6 does not support System.Activities anymore :

This Q&A points to :

It explains that one can use the Nuget package NuGet Gallery | UiPath.Workflow 6.0.3 should help us.

But it solves partly the problem.
To be continued …

Add this dll file to your project in visual studio
System.Activities.zip (1.2 MB)
Its a .net6.0 version of System.Activities , you can also find the same dll file in this path