C # Wpf PasswordBox I want to spy on the password

Good night, I have some PasswordBox and I would like to add buttons to spy on this password when the user needs it, I have tried to call PasswordRevealMode to the ############################################################################################ 39 inside PasswordBox, but it does not recognize it as a known command. I wonder if it has been interrupted or if I have to do something before. if this happens, how can I look at this password?