The UpdateBindingOnPasswordChanged is a very useful behavior which allows to bind the Password property of the PasswordBox Control. Use it, it's really simple.

Usage in WPF

1) Add the following XML namespaces:

xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
xmlns:catel="http://catel.codeplex.com"

2) Use the following definition:

<PasswordBox>
   <i:Interaction.Behaviors>
         <catel:UpdateBindingOnPasswordChanged Password="{Binding Password, Mode=TwoWay}" />
   </i:Interaction.Behaviors>
</PasswordBox>

Usage in Silverlight

1) Add the following XML namespaces:

xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
xmlns:catel="http://catel.codeplex.com"

2) Use the following definition:

<PasswordBox Password="{Binding Password, Mode=TwoWay}">
   <i:Interaction.Behaviors>
         <catel:UpdateBindingOnPasswordChanged />
   </i:Interaction.Behaviors>
</PasswordBox>