Injecting Dependencies into Domain Model classes with Nhibernate (ASP.NET MVC + IOC)

Question

I\'m building an ASP.NET MVC application that uses a DDD (Domain Driven Design) approach with database access handled by NHibernate. I have domain model class (Administrator) th

Answer 1

Is there a reason that you can't pass the IHashingService in the constructor for the Administrator class? That's how I would resolve the dependency.

public class Administrator
{
    private readonly IHashingService _hashingService;

    public Administrator(IHashingService hashingService)
    {
        _hashingService = hashingService;
    }

    // 

    public void SetPassword(string plainTextPassword)
    {
        this.HashedPassword = _hashingService.Hash(plainTextPassword);
    }
}

Edit #1

If pulling from a model, try using method-level injection.

public void SetPassword(string plainText, IHashingService hasher)
{
    if (hasher == null) throw new ArgumentNullException("hasher");
    this.HashedPassword = hasher.Hash(plainText);
}

Edit #2

Also, why not make it easy on yourself and just make an extension on string?

public static class ExtensionsOfString
{
    public static string Hash(this string s)
    {
        // hash with SHA256
        return hashedString;
    }
}

While I do realize that there's a "replaceable" code aspect of using dependency injection, this isn't exactly a big deal for this example. You don't really need a IPasswordEncryptionService the same way you'd need a, say, ICreditCardAuthorizationService. If, someday, you change your hashing algorithm from SHA256 to SHA512, you will now have invalidated every password in your database.