c# - What would cause a property get on an interface to fail? -

i have interface property, , class implements interface. cast instance of class interface, attempt read property , doesn't retrieve value. can see why?

interface:

public interface ifoo {     int objectid { get; } } 

class:

public class bar : ifoo {      public int objectid { get; set; } } 

usage:

... bar mybar = new bar() { objectid = 5 }; ifoo myfoo = mybar ifoo; int myid = myfoo.objectid;  //value of myfoo.objectid 5 in watch, myid remains @ 0 after statement ... 

this oversimplified, i'm doing. why can see value of myfoo.objectid in watch window, assignment myid fails (value 0 before , after assignment)?

you might have manipulated data on watch through manual intervention or statement changed value.

i did quick test on code in console application , value of myid 5.

class program {     static void main(string[] args)     {         bar mybar = new bar() { objectid = 5 };         ifoo myfoo = mybar ifoo;         int myid = myfoo.objectid;          console.writeline(myid); // 5          console.readline();     } }  interface ifoo {     int objectid { get; } }  class bar : ifoo {     public int objectid { get; set; } }