How to validate PasswordBox WPF

Question

I'm trying to make a validation for a PasswordBox. For making validations I followed this link, that shows how to validate on TextBox.

The problem comes with PasswordBoxes. Because its Password is not bindable due to security reasons, I tried to make a binding following this link (also explained here, for CodeProject users).

So, apparently, fantastic! I can bind my PasswordBox with its Password property, so then I can bind with my validation. But it ignores me...

This is a regular TextBox that I use and works fine:

<local:ErrorProvider Grid.Column="1" Grid.Row="2" >
    <TextBox Width="160" 
          HorizontalAlignment="Left" 
           Name="textBoxUserPass" 
           Text="{Binding Path=Password, UpdateSourceTrigger=Explicit}" />
 </local:ErrorProvider>

And this is the PasswordBox I tried to simulate:

<local:ErrorProvider Grid.Column="1" Grid.Row="2" >
      <PasswordBox Width="160"
          HorizontalAlignment="Left"
          Name="textBoxUserPass"
          local:PasswordBoxAssistant.BindPassword="True"
          local:PasswordBoxAssistant.BoundPassword="{Binding Path=Password, UpdateSourceTrigger=Explicit}" />
 </local:ErrorProvider>

This is how I get the BindingExpression for each TextBox:

BindingExpression beUserName = textBoxUserName.GetBindingExpression(TextBox.TextProperty);
if (beUserName != null) beUserName.UpdateSource();

And this is how I get it for the PasswordBox:

BindingExpression bePassword = textBoxUserPass.GetBindingExpression(PasswordBoxAssistant.BoundPassword);
if (bePassword != null) bePassword.UpdateSource();

If we made any mistake (defined on my Validation class), when I do this:

if (!beUserName.HasError && !bePassword.HasError)

each BindingExpression should say true of false depending on error validations. But for my PasswordBox never gets the value... Any idea?

Answer 1

As far as I remember, the only way to add validation on a PasswordBox is to throw a new ValidationException in the setter of the binding property for SecurePassword. The PasswordBoxAssistant will not help you with this.

Answer 2

Try setting ValidatesOnDataErrors=True and ValidatesOnExceptions=True on your binding:

<PasswordBox ...
   local:PasswordBoxAssistant.BoundPassword="{Binding Path=Password,
      UpdateSourceTrigger=Explicit, 
      ValidatesOnDataErrors=True, 
      ValidatesOnExceptions=True}"
/>

Answer 3

Set Mode=TwoWay on your binding

local:PasswordBoxAssistant.BoundPassword="{Binding Path=Password,Mode=TwoWay,
UpdateSourceTrigger=Explicit}"