workflow task summary throwing error specified cast is not valid using spmetal layer

Question

I have created share point data access layer with spmetal, everything is works fine but when I try to query with task summary list through SPMETAL it throws error I tried several techniques to cast , directly use this Iqueryable list but as I try to access it, "it throws error specified cast is not valid"

Any help or clue why is throwing this error

Answer 1

Its solved by changing the types of event type to string and duration field with double . that error was produced by SPMETAL wrong mapping while generating the layer form SharePoint.