Subsonic ActiveRecord fails on compilation due to GUID

I have just downloaded subsonic 3, but when I try to compile my website, I get some errors. The errors all seem to relate to cases where I use GUIDs as foreign key. One example is the code below, where CreatedBy is a foreign key to my membership table. I have highlighted the affected lines.

        public void Add(IDataProvider provider){

        **if(String.IsNullO开发者_如何学CrEmpty(this.CreatedBy))
            this.CreatedBy=Environment.UserName;**

        var key=KeyValue();
        if(key==null){
            var newKey=_repo.Add(this,provider);
            this.SetKeyValue(newKey);
        }else{
            _repo.Add(this,provider);
        }
        SetIsNew(false);
        OnSaved();
    }

            public void Add(string username){

        **this.CreatedBy=username;**
        Add();

    }
    public void Add(string username, IDataProvider provider){

        **this.CreatedBy=username;**
        Add(provider);
    }

user514090 - wouldn't you have to create the guid from the string 1st in your model along the lines of:

this.CreatedBy =  new Guid(username);

I know i had issues with guids before and tackled it in a way 'similar' to this.