title: Trouble with mongoDB. The property '_id' of type ... cannot use element name '_id'
body: <p>I use ASP .NET MVC4 WebAPI and i have some class</p>
  
  <pre><code>public class Recipe
  {
      [BsonId]
      [BsonRepresentation(BsonType.ObjectId)]
      public string _id { get; set; }
  
      [BsonElement]
      [Display(Name = "Title")]
      public string Title { get; set; }
  
      [BsonElement]
      [Display(Name = "Description")]
      public string Description { get; set; }
  
      [BsonElement]
      [Display(Name = "Cost")]
      public int Cost { get; set; }
  
      [BsonElement]
      [Display(Name = "CategoryId")]
      public string CategoryId { get; set; }
  
      [BsonElement]
      [Display(Name = "ProductList")]
      public List&lt;string&gt; ProductList { get; set; }
  
      [BsonConstructor]
      public Recipe(string title, string description, string type, int cost, List&lt;string&gt; productList)
      {
          Title = title;
          Description = description;
          CategoryId = type;
          Cost = cost;
          ProductList = productList;
      }
  }
  </code></pre>
  
  <p>Than i take some documents in mongoDB</p>
  
  <pre><code>var collection = database.GetCollection&lt;Recipe&gt;("Recipes");
  var doc = collection.FindAllAs&lt;Recipe&gt;(); // exception
  </code></pre>
  
  <p>Why i get this Exception</p>
  
  <p>"The property '_id' of type 'CourseServer.Models.Recipe' cannot use element name '_id' because it is already being used by property '_id'."</p>
  
  <p>I have class Person where i use same attributes and it works.</p>
  
  <pre><code>public class Person
  {
      [BsonId]
      [BsonRepresentation(BsonType.ObjectId)]
      public string _id { get; set; } // and other some fields
  </code></pre>