asp.net mvc - Input string was not in a correct format MVC -

i want convert session["price"] decimal , convert session["count"] integer

        doc.price = convert.todecimal(session["price"]);         doc.count = convert.toint16(session["count"]);  

i error

var stringvalue = session["price"].tostring(); if(!string.isnullorempty(stringvalue)) {     try {        doc.price = convert.todecimal(stringvalue);     }     catch(formatexecption ex) {         // should not have gotten here because frontend should gaurd against input values not number anyway        throw new validationexecption("price not number"); } 

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