c# - Is [CallerMemberName] slow compared to alternatives when implementing INotifyPropertyChanged? -

there articles suggest different ways implementing inotifypropertychanged.

consider following basic implementation:

class basicclass : inotifypropertychanged {     public event propertychangedeventhandler propertychanged;      private void firepropertychanged(string propertyname)     {         var handler = propertychanged;         if (handler != null)             handler(this, new propertychangedeventargs(propertyname));     }      private int sampleintfield;      public int sampleintproperty     {         { return sampleintfield; }         set         {             if (value != sampleintfield)             {                 sampleintfield = value;                 firepropertychanged("sampleintproperty"); // ouch ! magic string here             }         }     } } 

i'd replace one:

using system.runtime.compilerservices;  class betterclass : inotifypropertychanged {     public event propertychangedeventhandler propertychanged;     // check attribute in following line :     private void firepropertychanged([callermembername] string propertyname = null)     {         var handler = propertychanged;         if (handler != null)             handler(this, new propertychangedeventargs(propertyname));     }      private int sampleintfield;      public int sampleintproperty     {         { return sampleintfield; }         set         {             if (value != sampleintfield)             {                 sampleintfield = value;                 // no "magic string" in following line :                 firepropertychanged();             }         }     } } 

but read [callermembername] attribute has poor performances compared alternatives. true , why? use reflection?

no, the use of [callermembername] not slower upper basic implementation.

this because, according this msdn page,

caller info values emitted literals intermediate language (il) @ compile time

we can check il disassembler (like ilspy) : code "set" operation of property compiled same way :

so no use of reflection here.

(sample compiled vs2013)