[轉]Composite Keys With WebApi OData

public void MapDataServiceRoutes(HttpConfiguration config)
{
    var builder = new ODataConventionModelBuilder();

    var entity = builder.EntitySet<ODataPackage>("Packages");
    entity.EntityType.HasKey(pkg => pkg.Id);
    entity.EntityType.HasKey(pkg => pkg.Version);

    // snip
}

public class PackagesODataController : ODataController
{
    public IMirroringPackageRepository Repository { get; set; }

    public IQueryable<ODataPackage> Get()
    {
        return Repository.GetPackages().Select(p => p.ToODataPackage()).AsQueryable();
    }

    public IHttpActionResult Get(
        [FromODataUri] string id,
        [FromODataUri] string version)
    {
        var package = Repository.FindPackage(id, version);

        return package == null
          ? (IHttpActionResult)NotFound()
          : Ok(package.ToODataPackage());
    }
}

public class CompositeKeyRoutingConvention : IODataRoutingConvention
{
    private readonly EntityRoutingConvention entityRoutingConvention =
        new EntityRoutingConvention();

    public virtual string SelectController(
        ODataPath odataPath,
        HttpRequestMessage request)
    {
        return entityRoutingConvention
          .SelectController(odataPath, request);
    }

    public virtual string SelectAction(
        ODataPath odataPath,
        HttpControllerContext controllerContext,
        ILookup<string, HttpActionDescriptor> actionMap)
    {
        var action = entityRoutingConvention
            .SelectAction(odataPath, controllerContext, actionMap);

        if (action == null)
        {
            return null;
        }

        var routeValues = controllerContext.RouteData.Values;

        object value;
        if (!routeValues.TryGetValue(ODataRouteConstants.Key,
          out value))
            {
              return action;
            }

        var compoundKeyPairs = ((string)value).Split(',');

        if (!compoundKeyPairs.Any())
        {
            return null;
        }

        var keyValues = compoundKeyPairs
            .Select(kv => kv.Split('='))
            .Select(kv =>
              new KeyValuePair<string, object>(kv[0], kv[1]));

        routeValues.AddRange(keyValues);

        return action;
    }
}