Setting Up a C# Class Managed DLL for Unity Project (Window Development)

A. Setup Project

1. Install Visual Studio 2017 (with .Net Desktop Development tools, C# 4.6.1 and Game development with Unity)
2. Install Unity, and Mono
3. Create New Visual Studio Project
   • Select File > New > Project
   • On dialog, select Visual C# > Class Library (.NET Framework)
   • Setup Name, Location, and Solution Name
   • On Framework, Select .NET Framework 4.6.1 (or Unity compatible version)
4. Add UnityEngine reference
   1. Select Project > Add Reference
   2. Select Browse > Browse...
   3. Browse to \UNITYPATH\Editor\Data\Managed\UnityEngine.dll
   4. On Solution Explorer, select Reference > UnityEngine, then go to Properties, change Copy Local to False

B. Setup Debug Environment

1. Add a new Unity Project
2. At Visual Studio, select Project > $(ProjectName) Properties
3. Go to Build tab, Select Configuration Debug
4. Select Output Path to \UNITYPROJECTPATH\Assets\Debug (or any name under assets)
5. Go to Build Events tab, on Post-build event command line, insert: "\MONOPATH\bin\pdb2mdb" $(TargetDir)$(TargetFileName)
6. To debug, First build the project, then select Debug > Attach Unity Debugger
7. For VS Code debug:
   1. Install Debugger for Unity Extension
   2. On VS Code, Open directory containing .csproj
   3. Go to Debug tab, Setup launch.json
   4. Set the Path to \UNITYPROJECTPATH\Library\EditorInstance.json

C. Setup Common Macro/Properties

1. Setup Properties XML file:

<?xml version="1.0" encoding="utf-8"?>
<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
  <PropertyGroup>
    <MarcoName1>MarcoValue1</MarcoName1>
    <MarcoName2>MarcoValue2</MarcoName2>
    <DependentMarco3>$(MarcoValue2)Addon</DependentMarco3>
    ... 
    <MarcoNameN>MarcoValueN</MarcoNameN>
  </PropertyGroup>
</Project>

2. At .csproj file, add following line:

<Project ...>
  <Import ... />
  <!-- Add the following line -->
  <Import Project="Path\to\XmlFile" />
  ...
  <!-- And use MarcoName just like other marcos -->
    <HintPath>$(MarcoName1)...</HintPath>
  ...
</Project>

D. Note

1. Step A.4.4 prevent Visual Studio from copying UnityEngine.dll to output directory, which is an unnessary and project corrupting step
2. Mono is needed to generate debug symbol for unity debugging (Step B.5)
3. Not sure if $(TargetFileName) refers to 1 or 1+ dll (Step B.5)
4. On Step B.4, one may also choose to use default output path and simlink it to project directory
5. Only Unity version >=2018 support C# with .NET Framework 4.6.1.
6. (Unconfirmed) It seems that managed DLL project can be complied with 1 Unity version and be compatibale with other version.
7. Setup is tested with
   • Windows 10 Pro (Version 1809, OSBuild 17763.615)
   • Visual Studio 2017 (Version 15.9.14)
   • Mono (Version 6.0.0)
   • Unity (Version 2018.4.4f)

// 20190730_ll