CODEWITHSUNDEEP
visual-studiomsbuild
Jason Goemaat
Jason Goemaat

Reputation: 29194

Make visual studio build when output won't change?

In my project I have a json file I use for configuration that I have git set to ignore. When the repository is first cloned, the configuration file that is part of the project and that is copied to the output directory doesn't exist. I've gotten this to work using tasks in the 'BeforeBuild' target in the project that will copy the sample file to the actual config file if it doesn't exist. 

<Target Name="BeforeBuild">
  <ItemGroup>
    <MySourceFiles Include="Configuration.sample.json" />
  </ItemGroup>
  <ItemGroup>
    <MyDestinationFiles Include="Configuration.json" />
  </ItemGroup>
  <Message Importance="high" Condition="!Exists('@(MyDestinationFiles)')" 
           Text="Copying @(MySourceFiles) to @(MyDestinationFiles)" />
  <Copy Condition="!Exists('@(MyDestinationFiles)')" 
        SourceFiles="@(MySourceFiles)" 
        DestinationFiles="@(MyDestinationFiles)" />
</Target>

So if I build the project, then delete the configuration file and do a build, nothing happens because no changes have been made that would change the outputs I think. Is there a way to change the project file so that a build will be flagged as necessary? It shouldn't come up very often and I can always do a 'Clean' or 'Rebuild' manually, but it's nagging at me since I'm just starting to learn MSBuild files.

Upvotes: 1

Views: 49

Answers (1)

stijn
stijn

Reputation: 35901

From the documentation on a Target's Outputs attribute:

The files that form outputs into this target. Multiple files are separated by semicolons. The timestamps of the files will be compared with the timestamps of files in Inputs to determine whether the Target is up to date

So if you add the paths to the outputfiles created by your Beforebuild target to it's Outputs attribute, at the start of every build msbuild will check if those files exist and if not it will start a build because now the project is considered to not be up-to-date anymore. In practice use:

<Target Name="BeforeBuild" Outputs="@(MyDestinationFiles)">

Upvotes: 1

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