问题
We have a web site built with Orchard CMS v1.8. We have had a couple of instances where the person that manages content has not been able to save changes to a Page. They receive the following error.
An unhandled exception has occurred and the request was terminated. Please refresh the page. If the error persists, go back Sequence contains more than one matching element System.InvalidOperationException: Sequence contains more than one matching element at System.Linq.Enumerable.SingleOrDefault[TSource](IEnumerable
1 source, Func2 predicate) at Orchard.ContentManagement.DefaultContentManager.BuildNewVersion(ContentItem existingContentItem) in c:\Orchard\src\Orchard\ContentManagement\DefaultContentManager.cs:line 450 at Orchard.ContentManagement.DefaultContentManager.Get(Int32 id, VersionOptions options, QueryHints hints) in c:\Orchard\src\Orchard\ContentManagement\DefaultContentManager.cs:line 234 at Orchard.Core.Contents.Controllers.AdminController.EditPOST(Int32 id, String returnUrl, Action1 conditionallyPublish) in c:\Orchard\src\Orchard.Web\Core\Contents\Controllers\AdminController.cs:line 308 at lambda_method(Closure , ControllerBase , Object[] ) at System.Web.Mvc.ReflectedActionDescriptor.Execute(ControllerContext controllerContext, IDictionary2 parameters) at System.Web.Mvc.ControllerActionInvoker.InvokeActionMethod(ControllerContext controllerContext, ActionDescriptor actionDescriptor, IDictionary2 parameters) at System.Web.Mvc.Async.AsyncControllerActionInvoker.<BeginInvokeSynchronousActionMethod>b__39(IAsyncResult asyncResult, ActionInvocation innerInvokeState) at System.Web.Mvc.Async.AsyncResultWrapper.WrappedAsyncResult2.CallEndDelegate(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncControllerActionInvoker.EndInvokeActionMethod(IAsyncResult asyncResult) at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.b__3f() at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<>c__DisplayClass48.b__41() at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<>c__DisplayClass48.b__41() at System.Web.Mvc.Async.AsyncControllerActionInvoker.AsyncInvocationWithFilters.<>c__DisplayClass48.b__41()
What can I do to elimiate the extra record(s) returned in the SingleOrDefault() call? I don't know the database structure behind Orchard enough to find the "content records" but if I was able to find them I could delete the extra record(s).
Thanks!
回答1:
The cause for this error that you have more than one version of the same content item with value Latest = 1 (orchard use this value to determine the latest version for content item), to solve it you can run the following query to find the duplicate versions:
SELECT *
FROM Orchard_Framework_ContentItemVersionRecord
WHERE ContentItemRecord_id = @Id
then be sure that there is only one record with value Latest = 1, published = 1, and Number is in sequence without duplicates.
FYI, in query use value Id for content item which has the error.
来源：https://stackoverflow.com/questions/38645362/orchard-cms-duplicate-content-error