Resource not found for segment 'Property'

问题

When using ADO.Net Data Services client to refresh an entity by calling the LoadProperty:

ctx.BeginLoadProperty(this, "Owner", (IAsyncResult ar) => ...

It throws an error on the server if the property is null

Error: Exception Thrown: System.Data.Services.DataServiceException: Resource not found for the segment 'Owner'. at System.Data.Services.RequestDescription.GetSingleResultFromEnumerable(SegmentInfo segmentInfo) at System.Data.Services.DataService1.CompareETagAndWriteResponse(RequestDescription description, ContentFormat responseFormat, IDataService dataService)
at System.Data.Services.DataService1.SerializeResponseBody(RequestDescription description, IDataService dataService) at System.Data.Services.DataService1.HandleNonBatchRequest(RequestDescription description) at System.Data.Services.DataService`1.HandleRequest()

Problem is that the client does not know whether the property is null or just hasn't been populated yet. The property Owner is a link from a Vehicle to a Customer.

Any ideas what's wrong?

Thanks

回答1:

Querying on primary keys generate an exception when the key does not exist. The workaround is to add a dummy true expression in the condition (eg : 1==1 && item.Id == XXX).

Without the dummy expression the ADO.NET request is:

http: //localhost//test.svc/Role(XXX)

With the dummy condition, the request is:

http: //localhost//test.svc/Role()?$filter=true and (Id eq 1)

The expected behaviour (null returned) is correct in the second case.

回答2:

Set IgnoreResourceNotFoundException property of the service context to true:

svc.IgnoreResourceNotFoundException = true;

回答3:

I've received a "Resource not found for segment 'Property'" error also. Mine appears to be that in the where clause I am looking by primary key. I have found some resources that say it will throw an error (even when using FirstOrDefault()) when using a primary key that doesn't exist (as opposed to other where clauses that just do not provide results). I'd guess a similar thing is happening to yourself.

来源：https://stackoverflow.com/questions/505761/resource-not-found-for-segment-property