New Post: Property Grid with dynamic editors

The ResolveEditor() method is the one that will get called when the editor needs to be re-evaluated. So action has to be done in this method.
I believe you could define your ComboBox/TextBox in XAML and refer to it in code-behind via
var myComboBox = this.Resources["MyComboBox"] as ComboBox;
var myTextBox = this .Resources["MyTextBox"] as TextBox;