c# - from enum to generic type -

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• how use reflection call generic method? 7 answers

i have 2 class this

public class excel: document{  }  public class pdf: document{  } 

and base class document.

i have enum

public enum documenttype{     excel = 1,     pdf = 2 } 

i have core class generic method implemented method

public class manager{      loadfile<t> (stream stream) t: document{     ...     }  } 

can call loadfile method command this

type gettype(documenttype documenttype){     ... }  loadfile<gettype(documenttype.excel)>(mystream){     ... } 

i want have generic parameter created enum.

the error

< generic cannot applied operands of type 'method group'

for cases know type @ compile time, such "please load pdf, it's going pdf" - don't see reason @ generics @ all. you're not saving time on instantiating object stream data, , letting build itself.

// example class pdf : document {     public pdf(stream stream)     {          // load pdf data stream here     } } 

for cases don't know object type, "load file user selected, might pdf, might excel file", don't want worrying generics. instead, want function returns base document type - don't know type before loading (i.e. @ compile time, don't know - can't use generics):

document loadfromstream(stream stream) {     var typeofdocument = somemethodtofindthefiletypefromthestream(stream);     switch(typeofdocument)     {         case documenttype.pdf:             return loadpdffromstream(stream);  // returns pdf object         case documenttype.excel:             return loadexcelfromstream(stream);  // returns excel object         default:             throw new exception("document not supported type");     } } 

if need specific object, you'll need downcast using information within object (such document type enum) figure out type cast to.

there no silver-bullet generic solution i'm afraid. if know file type @ compile time, generics aren't saving anything. if don't - need conditional logic determine type (whether before or after loading, e.g. using file extension decide).

generics won't save time or make life easier here @ all.