Object type does not have an EF6 definable key

Question

Here is my code, although I have already clarified the key attribute, but there is still a problem.

public class Contacts { [Key] public int ContactId { get; set; } public string Name { get; set; } public string Address { get; set; } public string City { get; set; } public string State { get; set; } public string Zip { get; set; } [DataType(DataType.EmailAddress)] public string Email { get; set; } } 

The error I am getting is:

The Contact entity type does not have a key. Define a key for this entity type.
Object type: EntitySet "Contacts" is based on the type "Contacts", which does not have specific keys

Answer 1

If you use EF Code First (not listed in your question), you will need to change the ContactId property name to ContactId in order to negotiate an agreement with ClassName + Id to determine the key for your contact entity type.

See the first MSDN Code conventions: http://msdn.microsoft.com/en-us/data/jj679962.aspx

Answer 2

I know that this has already been answered in one way, but I wanted to publish a different approach for those who are faced with this.

This error occurred to me, even when I had a [Key] property defined that I wanted to designate as the primary key. The error that occurred during the Update-Database command was caused by the fact that my migration name (via Add-Migration) matches the name I wanted to add. This is because the Add-Migration team created a partial class that matched the name of the object.

For instance:

 public class Contacts { [Key] public int ContactId { get; set; } public string Name { get; set; } } 

Doesn't work on execution:

 Add-Migration Contacts Update-Database 

because the signature of the migration class looked like below, and the body did not contain a property with the [Key] attribute

 public sealed partial class Contacts 

To solve this problem, I removed the migration with the same name and changed the Add-Migration command:

 Add-Migration ContactsTable Update-Database