Question

I has some method, for example:

    public VAR GetAllPosts()
    {
        var post = from p in _db.Posts  select p;
        return post;
    }

How return var-type variable?

Answer 1

Based on your code, you know it’s going to be a enumeration of Posts, so return

public IEnumerable<Posts> GetAllPosts()
    {
        var post = from p in _db.Posts  select p;
        return post;
    }

or

public IEnumerable<Posts> GetAllPosts()
    {
        return from p in _db.Posts  select p;
    }

If you want to go hardcore you could use something like this, this is a generic type of T, you have to call the method with the desired type and inside it validate the type and do what you like.

  public List<T> GetData<T>()
  {
      //Validate the type and do something
      if (typeof(T) == typeof(MyClass))
      {
         List<MyClass> lst = new List<MyClass>();
         lst.Add(new MyClass { ClassProperty = "Value" });

         return lst as List<T>;
     }
     else // do something else
     {
       return null;
     }
   }

To call this method you pass the correct type

List<MyClass> list = GetData<MyClass>();

Hope it helps.