Lambda Expression in a Custom Class

Question

I can't use this code because Member isn't available in the UI.

public MemberViewModel GetSingle(Expression<Func<Member ,bool>> whereCondition ) 
{ 
    var member = this.MemberRepository.GetSingle( whereCondition ); 
    if (member != null) 
   { 
       return new MemberViewModel( member ); 
       // or however you map from member to its view model 
    } 
     return null; 
}

What would a custom class look like to replace the expression? It would flow like this...

 public MemberViewModel GetSingle(CustomClass where) 
{ 
  // Create customExp of type Expression<Func<DAL.EntityModels.Category, 
  // bool>> out of CustomObject
  // _categoryRepository.GetSingle(customExp);
  // Convert the resulting dataobject to corresponding view object
  // return the view object
}

Any help appreciated.

Answer 1

Could you use something similar to this and then call it from somewhere that has access to both T (Member) and TViewModel (MemberViewModel)?

    public static TViewModel GetSingle<T, TViewModel, TRepository>(Expression<Func<T, bool>> whereCondition, TRepository repository)
        where T : class, Entity
        where TViewModel : class, IViewModel<T>, new()
        where TRepository : IRepository<T>
    {
        T member = repository.GetSingle(whereCondition);
        if (member != null)
        {
            return new TViewModel().MapFrom(member);
            // or however you map from member to its view model 
        }
        return null;
    }