Get referenced project's path in T4 template?

Question

I have a solution that has a few projects in it. I'd like to create some T4 templates in one of my test projects to generate tests based on code in another project. The test project has a Project Reference to the other project. The problem I have is that I don't know how to get a file path to the edmx file I need to generate code from.

Example (pretend this is an ASCII-based Solution Explorer):

MySolution.sln
-> MyTests.csproj (C:\a\b\c\)
----> GeneratedTests.tt (C:\a\b\c\GeneratedTests.tt)
-> MyDAL.csproj (C:\x\y\z\)
----> MyModel.edmx (C:\x\y\z\MyModel.edmx)

How would my GeneratedTests.tt be able to get a file path for MyModel.edmx utilizing its project reference to it?

Answer 1

This doesn't work that way. You'll have to reference the dll by path (you can find that out with Host.ResolvePath and use the VolatileAssembly tag from the toolbox to be able to recompile it without restarting VS ) and use reflection to work on the Model.

Answer 2

You can use the macros for special directories such as $(ProjectDir), $(SolutionDir) from the template, and perhaps read the .sln or .csproj file to extract the directory for the other project.

Answer 3

This answer only works from within Visual Studio.

Set the "hostspecific" property of the T4 template. This gives you access to the Host property. Type cast Host to IServiceProvider to call GetService(typeof(DTE)). This lets you traverse the contents of the solution.

<#@ template language="c#" hostspecific="true"  #>
<#@ assembly name="EnvDTE" #>
<#@ import namespace="EnvDTE" #>
These are the projects in this solution:
<#
var serviceProvider = this.Host as IServiceProvider;
var dte = serviceProvider.GetService(typeof(DTE)) as DTE;
foreach (Project p in dte.Solution.Projects)
{
#>
    <#=p.Name#> at <#=p.FullName#>
<#
}
#>

Also see the example of the ITextTemplatingEngineHost interface on MSDN and T4 Architecture by Oleg Synch.