“The Id field is required” validation message on Create; Id not set to [Required]

Question

This is happening when I try to create the entity using a Create style action in Asp.Net MVC 2.

The POCO has the following properties:

public int Id          


        

Answer 1

I ran into this issue with a form in which I was adding "objects" to a list dynamically. Therefore, our users were able to add, remove or update. It all worked well except for the cases when new items were created. For this reason, in my case, excluding the Id property was not an option. The solution was to make the ID Nullable:

public int? Id { get; set; }

This way existing items will have a value and new ones will have null instead. Good stuff.