Setting Up a Solution

< Modding Tutorials

In this tutorial you will learn how to set up a solution, along with instructions on setting the output directory and files for more convenient building right into the Assemblies folder.

Requirements

• The manual option in this tutorial requires you to have set up a Source and Assemblies folder (the Visual Studio automatic option sets this up for you).
• You will want to have an IDE installed: Recommended IDE's.
  
  

Setting up a solution

Setting up can be different for different IDE's. Feel free to add complete instructions for your IDE of choice.

Visual Studio Community 2022

NOTE: Visual Studio 2022 is a rather heavy application (2-3 GB for basic functionality) but works out of the box. It is strongly recommended if you are on Windows and have a PC that can handle it. This tutorial is similar for other versions of Visual Studio.

First, ensure that you have the .NET desktop development workload feature installed. If you didn't select it during installation or if you aren't sure, you can click on Get Tools and Features under the Tools menu to check:

Option 1 (Manual Method):

1. Create a new class library project
   1. Once loaded, go to File -> New -> Project...
   2. Type "Class Library (.NET Framework)" in the search bar, and select the C# option.
      

      Installing the .NET framework
   3. Enter your project name.
   4. Choose a location, preferably:
      

      (RimWorldInstallFolder)/Mods/(YourModName)/Source

   5. Enter a solution name (optionally, tick "Place solution and project in the same directory")
   6. Make sure Framework is ".NET Framework 4.7.2"
2. In your project, set target framework and various other properties
   1. In your Solution Explorer (the panel usually located on the right), right click your project -> Properties (or expand your project and double click "Properties" with the wrench icon)
   2. Optional: Under Application, change your Assembly and Namespace names to anything of your choice
   3. Optional: You can go to Build -> Advanced... and set "Debugging information" to "Embedded" or "Portable" to remove the extraneous PDB file while also retaining full debug information. You can also set it to "None" to make your DLL smaller, but error stacktraces will have less useful information.
   4. Leave Advanced..., and set the Output Path to "..\..\Assemblies\" (Or wherever the Assemblies folder is)
3. Add references to RimWorld code
   1. Expand your project in Solution Explorer. Then right click "References" -> Add Reference...
   2. Click Browse...
   3. Navigate towards

      RimWorldInstallPath/RimWorld******_Data/Managed

      and select files:
      

      Assembly-CSharp.dll
      UnityEngine.CoreModule.dll

   4. Click "Add"
   5. Click "OK" to close the Reference Manager.
   6. Right-click on both Assembly-CSharp.dll and UnityEngine.dll and set Copy Local to False (Properties pane).

Option 2 (Using Nuget):

This option uses Krafs Rimworld Reference Package it is less involved than using reference assemblies and is the recommended method.

1. Follow the above up till Add references to RimWorld code
2. From the Tools menu, select NuGet Package Manager -> Package Manager Settings.
   1. In the Settings dialog, under Package Management, change the Default package management format to PackageReference.
   2. Click OK to close the dialog.
3. Open Nuget Manager and type Rimworld
4. Add Krafs Rimworld Reference

You can now continue as if you added the assemblies. Doing this makes your project portable, because RimRef can be downloaded by anyone and used from anywhere, unlike Rimworld's assemblies which can't be distributed.

Linux

On Linux it is possible to develop using .NET packages provided by Microsoft:

1. Install .NET by following the provided instructions.
2. If you use IDE, use it to build (no further details, not tested).
3. It is possible to build from CLI using a .csproj file. Find a mod that has description pointing to its GitHub sources and copy from there (example here), or use another way to create a .csproj file.
4. For building use a command like the following (substitute the proper .csproj file, change Release to Debug for a debug build):
   

   dotnet build <project file>.csproj /property:Configuration=Release

5. If you get errors, possibly the .csproj is Windows-specific and needs to be edited:
   1. You may need to fix paths (point them to .dll files in RimWorld/RimWorld*_Data/Managed, but it is generally better to use NuGet as described above in Option 2, as that is platform-independent).
   2. See other setups above for other settings (those IDEs write those settings to the .csproj files).

Note that .NET Framework from Microsoft is Windows-only, and some .csproj files do not build without it. Generally it seems those using Windows-specific paths are affected, while those platform-independent work fine. Either use Mono (see below), or use one that works. The example .csproj file linked above can usually be used as a drop-in replacement, with only properties in the first PropertyGroup needing adjustment. If you really want or need it, you can get .NET Framework from Mono, by additionally doing these steps:

1. Install Mono (refer to your distribution's instructions);
2. Change the build command to the following (4.7.2 is the .NET version from the .csproj file):
   

   FrameworkPathOverride=$(dirname $(which mono))/../lib/mono/4.7.2-api/ dotnet build <project file>.csproj /property:Configuration=Release

Rider (good for Mac)

JetBrains Rider is a great cross-platform C# IDE. Previously a paid product (with exceptions), it now offers a community license, making it free for non-commercial use.

1. Open Rider and click New Solution in the welcome dialog.
   1. Click Class Library under .NET on the left. The option may take a second to show up.
   2. Under Solution Name (and Project Name), enter the name of your mod.
   3. Set the Solution Directory to [your mod folder]/Source.
   4. Optionally check "put solution and project in the same directory." This is probably a good idea.
   5. Change Framework to .Net Framework 4.7.2.
      1. If you're on Windows and 4.7.2 does not show up as an option, you will have to install the "4.7.2 Dev Pack" from Microsoft.
      2. If you're on MacOS, you may see an error "mono is not found"; install mono from here. Additionally, if you do not have the option to choose .NET 4.7.2, you can create a project with the available NET option(s) and then manually edit the .csproj file to contain "<TargetFramework>net472</TargetFramework>" later.
   6. Click Create.
2. In the left side bar, expand your solution, right click your project (mod name with "C#" icon) and click Properties.
   1. In the Properties window, select Configurations > Debug on the left and uncheck Debug Symbols.
   2. For both configurations, change the Output Path to ../../Assemblies.
   3. Click OK.
3. Expand your project, right click Dependencies and click Reference.
   1. Click Add From.
   2. Browse to the folder with the RimWorld DLLs
      1. DLL Location for Mac: "/Users/[username]/Library/Application Support/Steam/steamapps/common/RimWorld/RimWorldMac.app/Contents/Resources/Data/Managed
      2. For Win10: "\Program Files (x86)\Steam\steamapps\common\RimWorld\RimWorldWin64_Data\Managed"
   3. Select both Assembly-CSharp.dll and UnityEngine.dll and click OK.
   4. Expand Assemblies under Dependencies. For both of the assemblies that you just added:
      1. Right click the assembly and click Properties.
      2. Uncheck "Copy Local" (you may need to scroll down) and click OK.

You're done! Note that Rider has a built-in decompiler—to view the source of a RimWorld class or method, just right-click its name and click Go To > Definition.

.NET Framework via Command Line

If you are on Windows and for some reason you don't want to use Visual Studio, you can also use the C# compiler that comes with the .NET Framework from within the terminal.

1. Install the .NET Framework.
2. (Optional) Adding the compiler to PATH.
   1. Search for "env" -> Edit system environment variables -> click on "Environment Variables" -> Edit the Path of the user variables -> Add the folder of csc.exe (Usually C:\Windows\Microsoft.NET\Framework\vX.X.XXXXX).
3. Find
   

   Assembly-CSharp.dll
   UnityEngine.CoreModule.dll

   in your game files(Usualy at: C:\Program Files (x86)\Steam\steamapps\common\RimWorld\RimWorldWin64_Data\Managed\).
4. Open a terminal and cd to the location of your .cs file.
5. Compile your .cs file (If you skipped adding csc.exe to path, replace it with its full filepath in the following command).
   1. It should look something like this:

      csc.exe /t:library /r:"C:\Program Files (x86)\Steam\steamapps\common\RimWorld\RimWorldWin64_Data\Managed\Assembly-CSharp.dll","C:\Program Files (x86)\Steam\steamapps\common\RimWorld\RimWorldWin64_Data\Managed\UnityEngine.CoreModule.dll" MyMod.cs

   2. The command is structured where:

      csc.exe

      is the compiler(or the whole filepath), and:

      /r:"...","..."

      is the filepath of both gamefiles from step 3, and:

      MyMod.cs

      is your C# source code.
6. Explanation:
   1. the /t flag sets it to be a .dll file.
   2. the /r flag references the game files(Not the decompiled source code, the game files).

Common issues

• Can't find the option to target .NET Framework 4.7.2? It may require additional installation steps. In Visual Studio, Tools => Get Tools and features => Individual Components => Select .NET Framework 4.7.2 development tools (or google installation instructions). Also make sure your project is a Class Library (.NET Framework). Not .NET Core or .NET Standard.

See also

• Writing custom code continues on setting up your solution.