Project references in GAT

Yesterday I spent more or less the entire day trying to figure out how to add references between projects while unfolding a solution template. Turns out it was wasn't that tricky once you get the hang of GAT... Here's a step-by-step instruction:

1. Add new arguments for the complete name of each project in the CreateSolution recipe:

   <Arguments>
   <Argument Name="BaseNamespace">
   <Converter Type="Microsoft.Practices.RecipeFramework.Library.Converters.NamespaceStringConverter, Microsoft.Practices.RecipeFramework.Library"/>
   </Argument>
   <Argument Name="ServiceName" Type="System.String"/>
   <Argument Name="RootNamespace">
   <Converter Type="Microsoft.Practices.RecipeFramework.Library.Converters.NamespaceStringConverter, Microsoft.Practices.RecipeFramework.Library"/>
   <ValueProvider Type="Evaluator"
   Expression="$(BaseNamespace).$(ServiceName)">
   <MonitorArgument Name="ServiceName" />
   <MonitorArgument Name="BaseNamespace" />
   </ValueProvider>
   </Argument>
   <Argument Name="BusinessEntitiesProjectName">
   <ValueProvider Type="Evaluator"
   Expression="$(RootNamespace).BusinessEntities">
   <MonitorArgument Name="RootNamespace" />
   </ValueProvider>
   </Argument>
   <Argument Name="DataAccessProjectName">
   <ValueProvider Type="Evaluator"
   Expression="$(RootNamespace).DataAccess">
   <MonitorArgument Name="RootNamespace" />
   </ValueProvider>
   </Argument>
   ...
   </Arguments>

   As you can see, the project names are created automatically when specifying a root namespace and a service name - but that isn't necessary for the solution to work.
2. In the Solution.vstemplate file, make sure to pass the arguments on as custom parameters:

   <TemplateContent>
   <ProjectCollection>
   <ProjectTemplateLink ProjectName="$BusinessEntitiesProjectName$">Projects\BusinessEntities\BusinessEntities.vstemplate</ProjectTemplateLink>
   <ProjectTemplateLink ProjectName="$DataAccessProjectName$">Projects\DataAccess\DataAccess.vstemplate</ProjectTemplateLink>
   </ProjectCollection>
   <CustomParameters>
   <CustomParameter Name="$BusinessEntitiesProjectName$" Value="$BusinessEntitiesProjectName$"/>
   <CustomParameter Name="$DataAccessProjectName$" Value="$DataAccessProjectName$"/>
   </CustomParameters>
   </TemplateContent>

3. Do the same for each project .vstemplate file:

   <CustomParameters>
   <CustomParameter Name="$businessentitiesprojectname$" Value="$BusinessEntitiesProjectName$"/>
   <CustomParameter Name="$dataaccessprojectname$" Value="$DataAccessProjectName$"/>

4. And finally, in the project where you want to add a reference, put a new ItemGroup that looks like this:

   <ItemGroup>
   <ProjectReference Include="..\$businessentitiesprojectname$\$businessentitiesprojectname$.csproj">
   <Name>$businessentitiesprojectname$</Name>
   </ProjectReference>
   </ItemGroup>

Oh, and there is an added bonus. If you use the same namespace names as project names, you can put things like this in any pre-generated content:

using $businessentitiesprojectname$;