missing return statement in factory pattern c# -

i have following code code says return statement missing, though have put them in switch list.

public imap map(string oldtheme)  {      switch (oldtheme)      {          case "archer": return new archer();          case "craftyblue": return new craftyblue();          case "minimal": return new minimal();          case "mintalicious": return new mintalicious();          case "misfit": return new misfit();          case "peach": return new peach();          case "queen": return new queen();          case "sketch": return new sketch();          case "takeaway": return new takeawaylemonfresh();          case "lemonfresh": return new takeawaylemonfresh();          case "vanilla": return new vanilla();          case "velvet": return new velvet();          case "victoriana": return new victoriana();          case "writer": return new writer();     } } 

you need handle case when oldtheme none of values check for.

depending on case, suggest throwing argumentexception know when happens. have added default case switch statement:

public imap map(string oldtheme) {     switch ( oldtheme )     {         case "archer": return new archer();         case "craftyblue": return new craftyblue();         case "minimal": return new minimal();         case "mintalicious": return new mintalicious();         case "misfit": return new misfit();         case "peach": return new peach();         case "queen": return new queen();         case "sketch": return new sketch();         case "takeaway": return new takeawaylemonfresh();         case "lemonfresh": return new takeawaylemonfresh();         case "vanilla": return new vanilla();         case "velvet": return new velvet();         case "victoriana": return new victoriana();         case "writer": return new writer();         default: throw new argumentexception("unexpected value of oldtheme");     } }