c# - Relationship not set to null -


I have a very simple EF operation that fails: the relationship between the two entities as shown in the code below Break:

The database was generated earlier in the database. Institutions are defined as: 

  Public Class Teacher {Public Entry ID (Receive; Set;} .. Public Virtual List & amp; Group & gt; Group {Receive; Set;}} public class group {public entry id (get; set;} .. public virtual teacher teacher {get; set;}}

However, breaking relationships does not work , The teacher keeps pointing to the same unit. Step along with the debugger I see that teacher property is not created after zero. Teacher = Null I tried it with synchronous option, which had the same effect: 

  Public Zero RemoveCurrentTeacherOfGroup (int groupId ) {Var group = _dataContext.Groups.Single (g = & gt; g.Id == group); group. Teacher = null; _dataContext.SaveChanges ();}
< P>

If teacher is not loaded you can not link it either on query (curious load) Include: 

  _dataContext.Groups.Include (g = & gt; G.Teacher). Single (G = & gt; GID == Group ID);

Or if lazy loading is enabled, then use the property to read before clearing it: 

  var teacher = group. teacher; group. Teacher = Null;

You can see that " teacher is not zero after setting it to null " because the debugger reads the property After reaching (lazy after loading it) after setting it to null . Before

null already pressed the value group you did not load it before the Teacher = null line (if you load it If you see property value to empty the debugger before , if EF is actually loaded after idle loading is enabled after accessing the property to read) So it will work as expected and break the relationship, because sh Eccentrically will be loaded


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