T4 engine not recognizing current project namespace

I am using VS 2010 (C#) T4 templates to generate code.

I need to iterate through all types within my project, shortlist entity poco classes and generate wrappers. The problem is, the project namespace is not being recognized.

Here is the solution structure:

namespace MySolution.Entities
{
    public class Employee { ... }
    public class Department { ... }
}

// Seperate project referenceing MySolution.Entities.
namespace MySolution.Database
{
    public partial class Context { ... }

    // Should generate Context.cs as a partial class with after iterating Syste.Types available in MySolution.Entities.
    Context.tt
}

Here is the text template:

<#@ template language="C#" #>
<#@ Output Extension=".cs" #>

namespace MySolution.Database
{
    public partial class Context:
        System.Data.Entity.DbContext
    {
<#
System.Type [] types = typeof(MySolution.Entities).Assembly.GetTypes();
for (int i=0; i < types.Count; i++)
#>
        public <#= types[i].Name; #> <#= types[i].Name; #> { get; set; }
    }
}

The above code generates an error: The type or namespace 'MySolution' cannot be found. Are you missing a using directive or an assembly reference? I then put the following line of code to include the assembly:

<#@ Assembly Name="..\MySolution.Entities\bin\x86\Release\MySolution.Entities.dll" #>

Now it gives me a different error: The host threw an exception while trying to resolve the assembly reference '..\..\..TrafficMonitor.Core\bin\x86\Release\TrafficMonitor.Library.dll'. The transformation will not be run. The following Exception was thrown: System.IO.FileLoadException: The given assembly name or codebase was invalid. (Exception from HRESULT: 0x80131047)

Any ideas on how to overcome this limitation?

You can't reference statically a assembly, which you haven't compiled yet (remember, that T4 runs before assemblies are being compiled) There exist a nice article, which you can take into account on How to use T4 to generate Decorator classes

You also should not reference assembly via <#@ Assembly Name, because T4 will operate on assembly, which you have already compiled, but T4 operates before compilation. So your workflow will be - compile application, run t4, recompile application with new sources from t4. And this each time after changed in source code, on which T4 is being operated.