MSBuild - 捕获原始属性值

Question

  <PropertyGroup>
    <RootNamespace>MyCustomNamespace</RootNamespace>
  </PropertyGroup>

  <!-- warn if not default -->
  <ItemGroup Condition="$(TargetServer) and '$(RootNamespace)' != '$(MSBuildProjectName)'">
    <MyWarnings Include="RootNamespace would be overridden">
      <Info>$(RootNamespace)</Info>
      <Code>MY0001</Code>
    </MyWarnings>
  </ItemGroup>

  <PropertyGroup Condition="$(TargetServer)">
    <RootNamespace>MyServer.$(AssemblyName)</RootNamespace>
  </PropertyGroup>

  <Target Name="ShowMyWarnings" AfterTargets="AfterBuild" Condition="'@(MyWarnings)' != ''">
    <Warning Text="@(MyWarnings) %(MyWarnings.Info)" Code="%(MyWarnings.Code)"/>
  </Target>

输出新值

警告 MY0001：RootNamespace 将被覆盖 MyServer.MyAssemblyName

但我想要项目定义时的属性值

警告 MY0001：RootNamespace 将被覆盖 MyCustomNamespace

阅读这个文档，看起来它是不可能的（在项目之前评估的属性），也许有一些解决方法？

Answer 1

由于在项目之前评估属性，因此应在属性评估阶段（在另一个属性中）捕获值。

  <Choose>
    <When Condition="'$(RootNamespace)' != '$(MSBuildProjectName)'">
      <PropertyGroup>
        <OldRootNamespaceValue>$(RootNamespace)</OldRootNamespaceValue>
      </PropertyGroup>
      <ItemGroup>
        <MyWarnings Include="RootNamespace would be overridden">
          <Info>$(OldRootNamespaceValue)</Info>
          <Code>MY0001</Code>
        </MyWarnings>
      </ItemGroup>
    </When>
  </Choose>