Is there anyway to #define Constant on a solution

问题:

Is There anyway to #define Constant on a Visual Studio Solution Basis?

One can define a constant on a csproject basis, and one can put #define constant in cs file, but I wonder whether one can define it on a vs sln basis?

回答1:

You can actually use a variation on Ritch's approach with common project settings. Essentially you have to make a single change to the end of each project file in your solution:

  <PropertyGroup Condition="'$(SolutionDir)' == '' or
                     '$(SolutionDir)' == '*undefined*'">
      <SolutionDir>..\..\</SolutionDir>
    </PropertyGroup>
    <Import Project="$(SolutionDir)CommonSettings.targets" />
  </Project>

Then you can define CommonSettings.targets to contain the solution wide settings.

  <Project xmlns="http://schemas.microsoft.com/developer/msbuild/2003"
           ToolsVersion="3.5">
      <PropertyGroup>
          <TacoBuild>true</TacoBuild>
      </PropertyGroup>
  </Project>

That's basically it unless you want to override or merge project settings already defined in each project. The link below discusses how to do this in some detail.

http://www.ademiller.com/blogs/tech/2007/12/common-project-settings-for-your-visual-studio-solution/

回答2:

I have another approach for doing this:

1. Edit global config file. For example in my case it's .netcf2.0 so it's $(MSBuildBinPath)\microsoft.compactframework.csharp.targets.

   Add the following line:

   <Import Project="$(SolutionDir)CommonSettings.targets" Condition="exists('$(SolutionDir)CommonSettings.targets')" />
   

   This is to tell MSBuild import the CommonSettings.targets if it's existed in your solution folder.

2. Create CommonSettings.targets under your solution folder.

   For example to define ABC symbol:

   <Project DefaultTargets="Build" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
       <PropertyGroup>
       <DefineConstants>$(DefineConstants);ABC</DefineConstants>
       </PropertyGroup>
   </Project>
   

回答3:

Indirectly there is. If you set an environment variable with a flag and run VS:

set TacoBuild=true
devenv.eve bigproject.sln

or launch MSBuild from the command line:

msbuild /p:TacoBuild=true

In your .csproj files you need to add a PropertyGroup:

<PropertyGroup Condition="'$(TacoBuild)'=='true'">
    <DefineConstants>$(DefineConstants);TacoBuild</DefineConstants>
</PropertyGroup>

In your code you need a preprocessor def:

#if TacoBuild 
    const int myConst = 42;
#endif

A VS only alternative is to define a preprocessor definition in the build settings for a new project configuration and use that configuration in your build.

A non MSBuild solution is to create a constants.cs file and write a custom settings tool that updates the cs file. I wish there were a better solution, but I haven't found one.

回答4:

This is possible for Unity projects. Creating a file called
mcs.rsp (targeting .Net 3.5 Equivalent) or
csc.rsp (targeting .Net 4.0 Equivalent )
in /Assets/ folder allows you to do that.

Example : /Assets/csc.rsp file includes:

-define:THIS_IS_MY_GLOBAL_PREPROCESSOR_CONSTANT
-define:ANOTHER_GLOBAL_PREPROCESSOR_CONSTANT

In the project, in any player or editor c# script:

#if THIS_IS_MY_GLOBAL_PREPROCESSOR_CONSTANT
        Debug.Log("THIS_IS_MY_GLOBAL_PREPROCESSOR_CONSTANT is defined"); // compiles 
#else
        Debug.Log("THIS_IS_MY_GLOBAL_PREPROCESSOR_CONSTANT is not defined");
#endif

Tested on Unity 2019.1.2

https://docs.unity3d.com/Manual/PlatformDependentCompilation.html