Sequence contains more than one matching element

Hi,
I'm experiencing this issue when I try to open the backend page to manage Pages. I receive this message in a javascript popup windows: "Sequence contains more than one matching element". Could anyone help me to resolve this issue? I cannot manage my website without access to that page.

Thanks in advance for your support

Davide Vernole

Hello Davide,

Please check the request and response from the web service that is called when you try to click on pages. Is this a new project, upgraded project or some old installation you are using?

Kind regards,
Ivan Dimitrov
the Telerik team

Hii Ivan,
here your are the request and response that I have captured by using Firebug:

Request
Host: local.knodev.com
User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; en-US; rv:1.9.2.15) Gecko/20110303 Firefox/3.6.15
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8
Accept-Language: en-us,en;q=0.5
Accept-Encoding: gzip,deflate
Accept-Charset: ISO-8859-1,utf-8;q=0.7,*;q=0.7
Keep-Alive: 115
Connection: keep-alive
X-Requested-With: XMLHttpRequest
SF_UI_CULTURE: it
Referer: local.knodev.com/.../Pages
Cookie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; .ASPXAUTH=95F3C8C122CB89FD69A2BC427F992C54C602DB9428B487FDC6EBF45A2034F84D67DCF80AC261DDBD0D92B3967CA2D8FEC6141FD4061AB2B2D5A515F4D4F072F3054B3AFBD07FBACFC19B0DF544576BA023645BCAF281074D93FEF125613DFC10088242C926CC4AF36948DB55000A7B2B2E5D24949E21EA0F418C163A5B0EF1681FBFAEC676EBA5A366A6CBCB35CF53AE

Response:
Cache-Control: private
Content-Length: 61
Content-Type: application/json
Server: Microsoft-IIS/7.5
Set-Cookie: .SFAUTH=3D3594A5D7A93D665FAAEA14B14057FC409728E032E0A1B8A79EDBF408358A55C2A56D736F1CFD5B84BCA668B6CD7ECC6067871B9AF8D94F85ABDC0A0992CD10B2F385BFA05C445AE465F78DBB9596FE711BC36AFC6363B9FCEDC2486B13829D312D3157E31B4C964F537163891CD79B4219453BABB48B9F16D1623BB6F4FF8E080C534C29FAF281E9C597C0FF36519BE846DC74BB7A861C6315D27349BC2A396B350B51BE4A32539A5C0EEDDF7B451FD7804A475C5BE2FC5AA1FBE532B35E09D7A7EA279CE6693551DB19B8CB9B2CBC3FA66A3E92B9360B449720E92AAB4FB248A94D7C3CFA99810EA05EC8EB973EE680BE54000C2206EAE50BCD3BA42FDCB3; expires=Mon, 07-Mar-2011 13:47:37 GMT; path=/; HttpOnly
X-AspNet-Version: 4.0.30319
X-Powered-By: ASP.NET
Date: Mon, 07 Mar 2011 11:47:37 GMT

Location:
local.knodev.com/.../

Response Body:
"Detail":"Sequence contains more than one matching element"

Calling the URL by hand I have received this reply:

File not found
Firefox can't find the file at local.knodev.com/.../ ASC.

This project in an upgrade from Sitefinity 4 to Sitefinity 4 SP1. The .svc file is in the right directory.

Cheers
Davide

Hi Ivan,
I have resolved the issue following an idea that Radoslav has shared with me. Cleaning the sf_draft_pages table from the duplicated draft pages that for any reason could be present in that table. In my support ticket I have suggested to Radoslav a change in your code to avoid this kind of issue again.

Thanks for your support

Same thing happens with me. I tried deleting the records in the sf_draft_page table, but no luck. It seems to happen with really long forms I think.

Sequence contains more than one matching element

[InvalidOperationException: Sequence contains more than one matching element]
   System.Linq.Enumerable.SingleOrDefault(IEnumerable`1 source, Func`2 predicate) +467
   Telerik.Sitefinity.Descriptors.DynamicFieldsTypeDescriptor..ctor(ICustomTypeDescriptor parent, Type type) +948
   Telerik.Sitefinity.Model.DynamicFieldsTypeDescriptionProvider.GetTypeDescriptor(Type objectType, Object instance) +354
   System.ComponentModel.DefaultTypeDescriptor.System.ComponentModel.ICustomTypeDescriptor.GetProperties() +63
   System.ComponentModel.TypeDescriptor.GetPropertiesImpl(Object component, Attribute[] attributes, Boolean noCustomTypeDesc, Boolean noAttributes) +412
   Telerik.Sitefinity.Model.DataExtensions.SetValue(IDynamicFieldsContainer dataItem, String fieldName, Object value) +33
   Telerik.Sitefinity.Modules.Forms.Web.UI.FormsControl.SaveFormEntry(FormDescription description) +565
   Telerik.Sitefinity.Modules.Forms.Web.UI.FormsControl.ProcessForm(FormDescription form) +137
   System.Web.UI.WebControls.Button.RaisePostBackEvent(String eventArgument) +145
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +3410

I'm having this problem on a project as well.   What records need to be cleaned out of the sf_draft_page table?   All of them or only those that are duplicates?

Thanks.

Hi Kevin,
in my case only the duplicate records. This has resolved my issue and now my web site is online.

Davide

I'm now getting this error.  This is a brand new project under Sitefinity 4.1. 

Clearing the sf_draft_pages table did not fix the issue.  I can create a new page, but when attempting to edit it, I get the error, "Sequence contains more than one matching element."

Also, when attempting to edit a single page, I see 2 new records get inserted into sf_draft_pages.  Is this normal?

I'm running into one issue after the next with Sitefinity...please help!

Thanks,
-Chris B.

Hi Chris Bryant,

Can you please outline the steps you take in order to reach the problem on the new website? Instead of clearing the page drafts table can you please try using a variation of the code below:

Hi,
  I am getting the same error, but mine pops-up as soon as I click on Pages in the backend administration. This started after I attempted moving my dev db to prod. I merged all my dev records with production without deleting anything on the live database. Given the lack of knowledge to know which table means what, or whether we can delete records from certain tables or not, we had to retain the production records. The website seems to be working fine, frontend, however the backend is having issues.

  The lists, templates seem to be okay. Only the Pages is the looming issue. We are going live today and would greatly appreciate any assistance.

Thanks,
Soumya

I had the same problem earlier, it seemed to be linked to a custom control of mine being incorrectly created. It had an error on creation as the Toolboxes.config file was not editable, so it was only partially created. To fix I had a backup of the DB just before, restored it, made sure the config files were writeable and then re-created the controls. You could probably achieve the same by just deleting the config sections in the administrative pages.

Hope this helps,

Dan

Thanks for your reply Dan.
How do I know which config file to clear and what should I clear?  
Everything is working, only the Pages is having this problem. I cannot go back to my old database cause I need to use the new one to move to production. If it helps I am getting a 500 error when I saw on Fiddler, the url is
Sitefinity/Services/Pages/PagesService.svc/?managerType=Telerik.Sitefinity.Modules.Pages.PageManager&providerName=&itemType=Telerik.Sitefinity.Pages.Model.PageNode&hierarchyMode=true&sortExpression=Title%20ASC
The same is working on Dev. I merged DEV database with production and palced it on Staging whereI am getting this error.

Any help would be greatly appreciated.

Thanks,
Soumya

Hi Soumya,

It sounds like to me that your database merge didn't work as expected and that in the process duplicate records have been created in some of the tables. I'm not overly familiar with a lot of the inner workings of Sitefinity so hopefully one of the admins will step in. Sorry I cant be much more help,
Dan

Hi Dan,

  Thanks a lot for replying back. Regarding the database merge I purposefully did not chose to delete the records on the target DB (production) cause I was not sure which records in which tables could go and which not. This is the price I am ready to pay till I get a better explanation from Sitefinity as to how to handle the merge or hopefully when they have the Site Synchro feature built in.. I will be eagerly waiting :)

  Coming to the error, I cleared the table of duplicates, I went of on is_temp_draft & page id as basis and tried to have only one of each combination.

 Now the errors are gone and everything working fine. I did have some more hiccups cause of the merge, of multiple controls of same id getting created on some pages, but I manually fixed them. I dont like this way, but will have to do till I find a more relaible way.

thanks again for your response.

soumya

I'm getting this same issue but on my Products page which is preventing me from creating any products. How can this issue be resolved?

Hello,

This issue for products can be caused if a users adds a custom field for a product type which has the same name as one of the default fields. We will add a validation that will prevent it from happening in a future version. 

Hi,
Sorry for the query on this old thread,but i am facing the same issue and getting error while deleting the sf_draft_pages .
first i truncated the reference table sf_drft_pages_sf_language_data, but still giving th error:
Cannot truncate table 'sf_draft_pages' because it is being referenced by a FOREIGN KEY constraint.
could you please suggest me what are the tables need to delete for the same?

Hello,

Would it be possible to share with us your exact scenario, please? It would be best if it can be done using the API, modifications directly in the database are not recommended and should be used only as a last resort. 

My Fix: 

- Try to figure out which Metafield caused this problem 
- It happened couple of time to  me because of the "Weight" metafield till I figured out that even after deleting the field, I have to make sure to delete it from CatallogConfig.config 
- To delete the field just run the following code 

the above function only deleted the fields from the database, so you'll nee to delete your custom field also from the config file mentioned above 

I am also getting this error, repeatedly.  It happens when creating a custom User Profile.  This is unacceptable... this error has been happening since 2011 (!) and the error message returned is next to useless.

Hello,

The error can occur if there multiple fields with the same name in the database/configurations and the system expects only one which in turn causes the error. I would like to suggest opening a ticket in order to get project and help you locate the field and fix the issue.


Regards,
Atanas Valchev
Telerik

Sitefinity support was able to fix my configuration file accordingly and solve my issue.  I still think that more care should be taken around this error.  Sitefinity should give you a descriptive error message, and ideally let you remove/replace the duplicate field.

Hello,

Recently we logged two bugs regarding custom fields in user profiles. Please find the bugs' descriptions on the following links:

http://feedback.telerik.com/Project/153/Feedback/Details/123459-custom-fields-with-same-names-could-be-added-to-custom-profiles

http://feedback.telerik.com/Project/153/Feedback/Details/123501-custom-fields-with-same-name-as-deleted-fields-could-be-added-to-custom-profiles

Regards,
Stefani Tacheva
Telerik

Thank you for acknowledging these bugs Stefani.

The fix for me turned out to be removing any reference to the bad product classification field from the catalogConfig file found here: /App_Data/Sitefinity/Configuration/CatalogConfig.config