Title
qListView ezEdit Display Fields edit screen error “httpvaluecollection.throwifmaxhttpcollectionkeysexceeded()” when accessing a list with large #’s of columns.Description
Cause
The MaxHttpCollectionKeys limit is being reached. Even though the columns are under the limit, QuickApps webparts provide more advanced features than the native SP webparts, QuickApps webparts require more parameters on the web form than the native SP webparts in order to provide this advanced functionality. This is why the native SP webparts can still work when QuickApps webparts begin to have this problem.Resolution
There are two workarounds for this issue:1. Increasing the MaxHttpCollectionKeys value temporarily and then change it back after finishing the configuration. (does not require an IISReset). This value can be set in the web.config file.
The setting in the web.config looks like this:
<appSettings>
<add key="aspnet:MaxHttpCollectionKeys" value="2000" />
</appSettings>
Where 2000 can be set to a number that works for your environment. Default it 1000.
or
2.Write the XML configuration manually