System.MissingMethodException after adding an optional parameter

Question

I am getting error of System.MissingMethodException after I have an optional parameter in one component and the other component which call it was not build as it call it with old number of parameters.
Only component in which parameter is added was build an deployed as patch. The calling component is old as there is no change in it.
When the calling component run it gives error :
Exception Information
Exception Type: System.MissingMethodException Message: Method not found: 'LabelURLs IPSD.BnB.Transaction.Postage.GetLabelURLs(System.String)'. Data: System.Collections.ListDictionaryInternal TargetSite: Void GenerateScanForm(Int32, Int32) HelpLink: NULL Source:
BnBDispenseQueueProcess
As far as i know it should not raise an error as new parameter is optional. One more thing calling component(EXE) run as windows service.
we found an very wired workaround to make it run. By Removing the changed component once and run calling component which will say DLL not found. The place the same DLL again and calling component works fine:).
I think i am missing some internals of .net.
Let me know if more info needed.

Answer 1

Hi, 
Type with only optional parameter constructor and no parameter less, will throw this exception when trying to create through Activator.CreateInstance
This issue is addressed here,
http://connect.microsoft.com/VisualStudio/feedback/details/521722/system-activator-createinstance-throws-system-missingmethodexception-with-constructor-containing-an-optional-parameter  
Is your component only have optional parameter constructor? 
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