Question

I have created a module that i want to collect some simple data in Orchard’s database, so i have created model, migration and handler for it:

Models/StatePartRecord.cs :

 namespace Address.Models
    {
        public class StatePart : ContentPart<StatePartRecord>
        {
            public int Id
            {
                get { return Record.Id; }
                set { Record.Id = value; }
            }
            public string StateName
            {
                get { return Record.StateName; }
                set { Record.StateName = value; }
            }
        }
    }

Models/StatePartRecord.cs :

namespace Address.Models
{
    public class StatePartRecord : ContentPartRecord
    {
        public virtual int Id { get; set; }
        public virtual string StateName { get; set; }
    }
}

Migrations.cs :

namespace Address
{
    public class Migrations : DataMigrationImpl
    {
        public int Create()
        {
            SchemaBuilder.CreateTable("StatePartRecord", table => table
                .ContentPartRecord()
                .Column<string>("StateName")
                );

            return 1;
        }
        public int UpdateFrom1()
        {
            ContentDefinitionManager.AlterPartDefinition("State", part => part
                .Attachable());

            return 2;
        }

    }
}

Handlers/StatePartHandler.cs :

namespace Address.Handlers
{
    public class StatePartHandler : ContentHandler
    {
        public StatePartHandler(IRepository<StatePartRecord> repository)
        {
            Filters.Add(StorageFilter.For(repository));
        }
    }
}

Services/MyService.cs :

namespace Address.Services
{
    public class AddressService : IAddressService
    {
    ...
     public void InsertState(Models.StatePartRecord state)
     {
         _stateRepository.Create(state);
     }
    ...
}

now in written service class for my module, when i try to create an item and save it in database it trows an exeption:

attempted to assign id from null one-to-one property: ContentItemRecord

Note that _stateRepository is a IRepository<StatePartRecord> typed injected object.

what is wong?

Answer 1

This is because ContentPartRecord has a ContentItemRecord property that points to the ContentItemRecord corresponding to the content item the ContentPartRecord’s Part is attached to.

You don’t have to manage part records directly: Orchard services (mainly ContentManager) does this for you. Even if you want to modify records on a lower level you should do this through ContentManager (by injecting an IContentManager). Only manipulate records directly if they’re just “plain” records you use to store non-content data, i.e. that aren’t ContentPartRecords.

        // MyType is a content type having StatePart attached
        var item = _contentManager.New("MyType");

        // Setting parts is possible directly like this.
        // NOTE that this is only possible if the part has a driver (even if it's empty)!
        item.As<StatePart>().StateName = "California";

        _contentManager.Create(item);