Developer forum

Forum » Dynamicweb 9.0 Upgrade issues » Value cannot be null when adding product custom field

Value cannot be null when adding product custom field

Scott Forsyth Dynamicweb Employee
Scott Forsyth


There appears to be a regressive bug in 9.10.7. We have it on 4 upgrades that we've done so I don't believe it's isolated to a particular site. When you try to add a new custom product field in the backend, you'll receive the error message below (simply by clicking the New Field button).

[ArgumentNullException: Value cannot be null.
Parameter name: key]
   System.ThrowHelper.ThrowArgumentNullException(ExceptionArgument argument) +49
   System.Collections.Generic.Dictionary`2.FindEntry(TKey key) +14545850
   System.Collections.Generic.Dictionary`2.TryGetValue(TKey key, TValue& value) +20
   Dynamicweb.Ecommerce.Products.FieldOptionCache.GetOptionsByFieldId(String fieldId, Int32 skip, Int32 take, String searchText, String languageId) +129
   Dynamicweb.Ecommerce.Products.FieldOption.GetOptionsByFieldId(String fieldId) +63
   Dynamicweb.Admin.eComBackend.EcomFieldEdit.SetControlsState(String fieldId, Boolean IsStandardEditable) +505
   Dynamicweb.Admin.eComBackend.EcomFieldEdit.Page_Load(Object sender, EventArgs e) +853
   System.Web.UI.Control.OnLoad(EventArgs e) +106
   System.Web.UI.Control.LoadRecursive() +68
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +3785

I found that if I compiled the latest Dynamicweb.Ecommerce.dll from source, it worked, so I assume that someone has just fixed this. I assume that this will come in 9.10.8. We have a pretty pressing customer impacted by this. Will that indeed be fixed in 9.10.8, and if so, when is 9.10.8 slated to be released?




Oleg Rodionov Dynamicweb Employee
Oleg Rodionov

Hi Scott,

It's known issue bugged by Bug 1489 in DevOps, it has just been fixed by Dynamicweb.Ecommerce 1.10.46 will be available in upcoming DW9.10.8 or can be download from nuget

BR, Oleg QA

Scott Forsyth Dynamicweb Employee
Scott Forsyth

Hi Oleg,

Thanks! I've downloaded Dynamicweb.Ecommerce 1.10.46 and confirmed that it fixes the issue. That gets us back on track.

Thank you,


Kristian Kirkholt Dynamicweb Employee
Kristian Kirkholt
This post has been marked as an answer

Hi Scott

Hotfix version 9.10.8 containing the bug has been released 

Download from

Kind Regards
Dynamicweb Support
Kristian Kirkholt

Votes for this answer: 1
Scott Forsyth Dynamicweb Employee
Scott Forsyth

Thanks Kristian. 


You must be logged in to post in the forum