Question

I am getting this error in my MVC Application:

One or more validation errors were detected during model generation:

System.Data.Edm.EdmEntityType: : EntityType 'CustomerModel' has no key defined. Define the key for this EntityType.
System.Data.Edm.EdmEntitySet: EntityType: EntitySet �Customer� is based on type �CustomerModel� that has no keys defined.

My Customer Model looks like this:

public class CustomerModel
{
    public string Name { get; set; }
    public int CustomerID { get; set; }
    public string Address { get; set; }
}

public class CustomerContext : DbContext
{
    public DbSet<CustomerModel> Customer { get; set; }
}

Answer 1

By default, Entity Framework assumes a key property called Id exists in your model class. Your key property is called CustomerID, so Entity Framework can’t find it.

Either change the name of your key property from CustomerID to Id, or decorate the CustomerID property with the Key attribute:

public class CustomerModel
{
    public string Name { get; set; }

    [Key]
    public int CustomerID { get; set; }

    public string Address { get; set; }
}

public class CustomerContext : DbContext
{
    public DbSet<CustomerModel> Customer { get; set; }
}