c# - Notify when the binding of Dependency Property is changed -

i need debug binding setup of given dependency property. @ beginning, set binding dependency property given source instance, following code:

var binding = new binding(path);             binding.source = source;             binding.mode = twoway ? bindingmode.twoway : bindingmode.oneway;             binding.updatesourcetrigger = updatesourcetrigger.propertychanged;             binding.converter = valueconverter;             var bindingresult = bindingoperations.setbinding(this, modelvalueproperty, binding);              var bindingexpression = bindingoperations.getbindingexpression(this, modelvalueproperty); 

bindingexpression not null , status of binding active. after view manipulations, when try bindingexpression null. how catch binding replacement or change on given dependency property ?

edit: in way, want know how notified when bindingexpression changes status active detached

you need set property:

binding.notifyonsourceupdated = true 

and register sourceupdated event of control you're bound (in case, it's this ):

        this.sourceupdated += (s, args) =>                                   {                                       // catch changes there                                   }; 

alternatively, can catch changes made directly on dependencypropertywith dependencypropertydescriptor:

            var descriptor =  dependencypropertydescriptor.fromproperty(modelvalueproperty, typeof(yourtype));             descriptor.addvaluechanged(this, onvaluechanged);               private void onvaluechanged(object sender, eventargs e)             {                 //...             }