c# - Re-assigning a new model in MVVM -> does not update child collection view models -

i have root model ~ propertyportfolio ~ save/load xml file. contains child collection of property objects.

when load application load object propertyportfolioservice. model uses inotifypropertychanged, service - i've got covered.

i have child view displays child collection of property objects in grid. binding works fine.

the problem have this:

when open new propertyportfolio file re-assign propertyportfolio object in service:

this.propertyportfolio = loadedpropertyportfolio; 

the child view/viewmodel not update.

the solution have load new portfolio , recreate child objects, this:

propertyportfolio loadedpropertyportfolio = /* code load new portfolio xml */;  this.propertyportfolio.properties.clear();  foreach (var property in loadedpropertyportfolio.properties) {     this.propertyportfolio.properties.add(property); } 

i'm looking better solution.

i hope that's descriptive enough?

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further information - problem propertyviewmodel (which contains property model object plus isselected logic).

this vm individual property (for each property in collection):

public class propertyviewmodel { public property property { { return this.property; } }

public bool isselected {     { return this.isselected; }     set     {         setproperty(ref this.isselected, value, () => isselected);     } }  public propertyviewmodel(property property) {     this.property = property; }  // other code (fields etc) 

}

this view model properties view (containing grid):

public class propertiesviewmodel : viewmodelbase {     public observablecollection<propertyviewmodel> propertyvms     {         { return this.propertyvms; }     }      public propertiesviewmodel(propertyportfolio propertyportfolio)     {         func<property, propertyviewmodel> viewmodelcreator = model => new propertyviewmodel(model);         this.propertyvms = new observableviewmodelcollection<propertyviewmodel, property>(propertyportfolio.properties, viewmodelcreator);     }      // other code (fields etc) }