Unity application block 2.0 - The given assembly name or codebase was invalid

Question

Interfaces (In the assembly named "Interfaces". In project :- Interfaces)

namespace Interfaces
{
    public interface IDoSomeWork1
    {
        string DoSomeWork1();
    }
}

namespace Interfaces
{
    public interface IDoSomeWork2
    {
        string DoSomeWork2();
    }
}

Dependencies (In the assembly named "Entities". In project :- Entities)

namespace Entities
{
    public class ClassB : IDoSomeWork1
    {
        public string DoSomeWork1()
        {
            return this.ToString();
        }
    }
}

namespace Entities
{
    public class ClassC : IDoSomeWork2
    {
        public string DoSomeWork2()
        {
            return this.ToString();
        }
    }
}

Class (In project :- UsingUnity)

public class ClassA
    {
        [Dependency]
        public IDoSomeWork1 DoSomeWork1 { get; set; }
        [Dependency]
        public IDoSomeWork2 DoSomeWork2 { get; set; }


        public void SomeMethodInClassA()
        {
            Console.WriteLine(DoSomeWork1.DoSomeWork1());
            Console.WriteLine(DoSomeWork2.DoSomeWork2());
        }
    }

App.Config (In a console application project :- ConsoleUsingUnity)

<?xml version="1.0" encoding="utf-8" ?>
<configuration>
    <configSections>
        <section name="unity"
                 type="Microsoft.Practices.Unity.Configuration.UnityConfigurationSection,
                   Microsoft.Practices.Unity.Configuration" />
    </configSections>
    <unity>
        <containers>
            <container>
                <types>
                    <type type="Interfaces.IDoSomeWork1, Interfaces"
                          mapTo="Entities.ClassB, Entities" />
                    <type type="Interfaces.IDoSomeWork2, Interfaces"
                          mapTo="Entities.ClassC, Entities" />
                </types>
            </container>
        </containers>
    </unity>
</configuration>

The client (In a console application project :- ConsoleUsingUnity)

public class Class1
    {
        static void Main(string[] args)
        {
            IUnityContainer container = new UnityContainer();

            // Load from config file
            UnityConfigurationSection section = (UnityConfigurationSection)ConfigurationManager.GetSection("unity");
            section.Configure(container);

            ClassA classA = container.Resolve<ClassA>();
            classA.SomeMethodInClassA();
        }
    }

And when I run the client, I get the following error at section.Configure(container);:-

The given assembly name or codebase was invalid. (Exception from HRESULT: 0x80131047)

I am not sure If there is anything wrong with the config or the type. Could anyone please point out the mistake here?

Answer 1

Before I answer my question, I must state that the code posted above didn't give me any problem (build error etc.). It just gave me the error I stated in my question. The problem with Unity at this point of time is that It does not provide which assembly or a which types in the assembly could not be loaded. This is a requested feature.

In my case It was a missing assembly problem. I didn't reference Entities assembly in to the client application project. It seems that that "Entities" assembly could be resolved only at the run-time (since it didn't give me any compile time error). However, the run-time error was also not useful at all.

I had a look a Fusion Log viewer (It should be in the .NET SDK folder). What a gem of an utility It is. It can log all kind of assembly bindings (all or only failures) and It give a very neat description of which assembly could not load. Very helpful!

So, next time, you get this "The given assembly name or codebase was invalid" error, try Fusion Log Viewer. It wont help you in finding which types couldn't be loaded. However,at least you will be sure all your assemblies are getting loaded correctly.