Question

Using the following code, assume I have 5 different types that I might receive in the variable type. Instead of writing 5 conditional statements, is there a way to write one and use the variable “type” to dictate what the model is, in this case “CommentVote?” Or is this more a deficiency in the way I’ve designed the data model with each of those 5 things having a “vote” model?

 if (type == "comment")
 {
      CommentVote voteObj = db.CommentVotes
           .Where(x => x.UserID == UserID && x.CommentID == id)
           .SingleOrDefault();
      if (voteObj != null)
      {
          voteObj.Vote = vote;
          db.SaveChanges();
      }
      else
      {
          CommentVote c = new CommentVote { 
               CommentID = id, UserID = UserID, Vote = vote, DateCreated = DateTime.Now 
          };
          db.CommentVotes.Add(c);
          db.SaveChanges();
      }

      count = (db.CommentVotes.Count(x => x.CommentID == id && x.Vote == true) - db.CommentVotes.Count(x => x.CommentID == id && x.Vote == false));
 }

Magic Code: The stuff I would love to be able to do.

 var modelName = "";
 var modelOtherName = "";
 if (type == "comment") {
      modelName = CommentVote;
      modelOtherName = CommentVotes;
 }

      modelName voteObj = db.modelOtherName
           .Where(x => x.UserID == UserID && x.CommentID == id)
           .SingleOrDefault();

Update: I’m beginning to think my model may be crap based on some of the reading referenced bellow. So I am including some of that as a reference. Let me know if that’s the problem I should be trying to solve.

 public class CommentVote
 {
    public int CommentVoteID { get; set; }
    public bool Vote { get; set; }
    public DateTime DateCreated { get; set; }
    public int UserID { get; set; }
    public virtual User User { get; set; } 

    public int CommentID { get; set; }  //This row changes from model to model
    public virtual Comment Comment { get; set; }  //This row changes from model to model
 }

I have a handful of models that are almost identical.

Answer 1

You can absolutely reduce the code to a single statement assuming that you perform the same actions and set the same data. In this case, you should have an interface that contains the common actions and data and an object factory to instantiate the correct object based on the type.