Actually, if you can change your viewing model and make formatting in the property, you will get much better performance than relying on IValueConverter.
I am using a template along these lines to still notify me of property changes
string _value; public string Value { get { return _value; } set { _value = value; NotifyPropertyChanged("Value"); NotifyPropertyChanged("ValueFormatted"); } } public string ValueFormatted { get { return "Static Text: " + _value; } }
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