加入项目组的MSBuild元数据

Question

我有两个物品组，希望将它们合并：

  <ItemGroup>
<ServerTypeA Include="ServerA;ServerB;">
  <MetaDataA>A</MetaDataA>
</ServerTypeA>
</ItemGroup>

  <ItemGroup>
<ServerTypeB Include="ServerB;ServerC;">
  <MetaDataB>B</MetaDataB>
</ServerTypeB>
</ItemGroup>

使用常规的join将给我一个包含4个项目的集合：

ServerA with Metadata A;
ServerB with Metadata A;
ServerB with Metadata B;
ServerC with Metadata B;

如何创建以下集合：

ServerA with Metadata A
ServerB with Metadata A & B
ServerC with Metadata B

- sagie

Answer 1

这是可以做到的。您可以手动执行连接操作。

以下是一个示例（需要msbuild 3.5或更高版本）：

<ItemGroup>
  <ServerTypeA Include="ServerA;ServerB;">
    <MetaDataA>A</MetaDataA>
  </ServerTypeA>

  <ServerTypeB Include="ServerB;ServerC;">
    <MetaDataB>B</MetaDataB>
  </ServerTypeB>
</ItemGroup>

<Target Name="JoinServers" DependsOnTargets="ProcessServerTypeA;ProcessServerTypeB">
  <Message Text="%(Joined.Identity) Metadata: %(Joined.MetaDataA)%(Joined.MetaDataB)"/>
</Target>

<!--Create -->
<Target Name="ProcessServerTypeA">
  <ItemGroup>
    <Joined Include="%(ServerTypeA.Identity)">
      <MetaDataA>%(ServerTypeA.MetaDataA)</MetaDataA>
    </Joined>
  </ItemGroup>
</Target>

<!--Need to batch at the target level for this to work-->
<Target Name="ProcessServerTypeB" Inputs="@(ServerTypeB)" Outputs="%(ServerTypeB.Identity)'">

  <PropertyGroup>
    <!--Create Temporary Properties for the Item Metadata-->
    <TempItemName>%(ServerTypeB.Identity)</TempItemName>
    <TempMetaDataB>%(ServerTypeB.MetaDataB)</TempMetaDataB>
    <!--Does the current item already exist?-->
    <TempIsDuplicate Condition="'%(Joined.Identity)' == '$(TempItemName)'">True</TempIsDuplicate>
  </PropertyGroup>

  <ItemGroup>
    <!--Update the existing item's metadata if this is a duplicate-->
    <!--Don't provide the include attribute.  This will allow you to update existing items metadata-->
    <!--Have to reference %(Joined.Identity) in the condtion to ensure we only update the correct item-->
    <!--You cannot directly reference metadata from ServerTypeB here.  Hence the need for the temp Properties-->
    <Joined Condition="'%(Joined.Identity)' == '$(TempItemName)'">
      <MetaDataB>$(TempMetaDataB)</MetaDataB>
    </Joined>

    <!--Create a new item if current item is not a duplicate-->
    <Joined Include="$(TempItemName)" Condition="'$(TempIsDuplicate)' != 'True'">
      <MetaDataB>$(TempMetaDataB)</MetaDataB>
    </Joined>
  </ItemGroup>
</Target>

运行JoinServers目标将产生以下输出：

ServerA Metadata: A
ServerB Metadata: AB
ServerC Metadata: B

更新更好的答案

这个问题指向了一个更简单的解决方案。

基本上，您可以使用转换修饰符和%(Identity)来执行连接。

您可以用以下代码替换上面的所有3个目标，以获得相同的输出。

<Target Name="JoinServers">
  <ItemGroup>
    <Joined Include="%(Identity)">
      <MetaDataA>@(ServerTypeA->'%(MetaDataA)')</MetaDataA>
      <MetaDataB>@(ServerTypeB->'%(MetaDataB)')</MetaDataB>
    </Joined>
  </ItemGroup>

  <Message Text="%(Joined.Identity) Metadata: %(Joined.MetaDataA)%(Joined.MetaDataB)"/>
</Target>

- Aaron Carlson

---

不错。我缺少的是ProcessServerTypeB目标的批处理。 - sagie