You have a few problems
First, your data context needs to be set in your view code behind
this.Datacontext = //your view model
Second, Your WordsViewModel class needs to implement INotifyPropertyChanged
Third your OnPropertyChanged
Signature is wrong.
It should look like the below example
Also you shouldn't be using your actual PropertChanged event handler. Its not thread safe.
Instead, clone it within your OnPropertyChanged
event
void OnPropertyChanged(String prop){
PropertyChangedEventHandler handler = PropertyChanged;
if(handler != null){
PropertChanged(this,new PropertyChangedEventArgs(prop));
}
}
Finally in your Left
property invoke OnPropertyChanged("Left");