Parsing list to an activity

hi, how can i parse this

List<WinTAP.PartialBusiness.clsExtraFactor> ExtraFactorLists = new List<WinTAP.PartialBusiness.clsExtraFactor>();

to an activity. I have googled and got this :

Intent.PutParcelableArrayListExtra("ExtraFactorLists", ExtraFactorLists);

OR ... i used :

IList<IParcelable>

Intent.PutParcelableArrayListExtra("ExtraFactorLists", (IList<IParcelable>)ExtraFactorLists);

i get error ....

cannot cast from source type to destination type

thanks in advanced !