WPF PasswordBox losing the zero characters from password - wpf-controls

Question

Hi Can anybody help me on this please?
I am tasked with fixing a bug in a login procedure in WPF (which I have no previous experience of!)
The problem seems to be that a PasswordBox control is ignoring zeros in the entered password. I have checked when password changes and examined the value entered - it definitly disgards the '0' characters. Example passwords should be 'password012' but what comes back from Passwordbox is 'password12' similary '0password' returns 'password'.
The username entry (TextBox control) seems fine.
Can anybody advise how to overcome this please?
The xaml code is here
<TextBox VerticalAlignment="Center" HorizontalAlignment="Center" Margin="0,10,0,48" Foreground="DarkSlateGray" Grid.Column="1" Grid.Row="1" Text="{Binding Username}" Name="txtUsername" Height="26" HorizontalContentAlignment="Center" Style="{StaticResource RoundTextBoxStyle}" Width="200" IsUndoEnabled="False" Effect="{StaticResource TextBoxDropShadow}" FontFamily="{StaticResource TextBoxDescrptionFontFamily}" FontSize="{StaticResource TextBoxDescriptionFontSize}" GotFocus="TxtBoxGotFocus" ToolTip="Enter your Username." Background="{StaticResource TextBoxBackground}"/>
<PasswordBox Grid.Column="1" Foreground="#FF2F4F4F" Margin="0,0,0,-36" VerticalAlignment="Center" Grid.Row="1" HorizontalAlignment="Center" Height="26" HorizontalContentAlignment="Center" MaxLength="0" w:PasswordBoxBinder.Attach="True" Style="{StaticResource RoundTextBoxStyle}" w:PasswordBoxBinder.Password="{Binding Path=Password, Mode=TwoWay}" Effect="{StaticResource TextBoxDropShadow}" Width="{Binding ElementName=txtUsername, Path=Width}" ToolTip="Enter your Password." GotFocus="PbxGotFocus" FontFamily="{StaticResource TextBoxDescrptionFontFamily}" FontSize="{StaticResource TextBoxDescriptionFontSize}" Background="{StaticResource TextBoxBackground}" PasswordChanged="PasswordBox_PasswordChanged" />
The code for PasswordBox_PasswordChanged was added by myself for debug purposes to find out what was happening.
private void PasswordBox_PasswordChanged(object sender, RoutedEventArgs e)
{
// ... Display Password in Title.
// A bad design decision.
var box = sender as PasswordBox;
this.Title = "Password typed: " + box.Password;
}
The code for PasswordBoxBinder is here and is part of the original code:
public static class PasswordBoxBinder
{
//test
public static readonly DependencyProperty PasswordProperty =
DependencyProperty.RegisterAttached("Password",
typeof(string), typeof(PasswordBoxBinder),
new FrameworkPropertyMetadata(string.Empty, OnPasswordPropertyChanged));
public static readonly DependencyProperty AttachProperty =
DependencyProperty.RegisterAttached("Attach",
typeof(bool), typeof(PasswordBoxBinder), new PropertyMetadata(false, Attach));
private static readonly DependencyProperty IsUpdatingProperty =
DependencyProperty.RegisterAttached("IsUpdating", typeof(bool),
typeof(PasswordBoxBinder));
public static void SetAttach(DependencyObject dp, bool value)
{
dp.SetValue(AttachProperty, value);
}
public static bool GetAttach(DependencyObject dp)
{
return (bool)dp.GetValue(AttachProperty);
}
public static string GetPassword(DependencyObject dp)
{
return (string)dp.GetValue(PasswordProperty);
}
public static void SetPassword(DependencyObject dp, string value)
{
dp.SetValue(PasswordProperty, value);
}
private static bool GetIsUpdating(DependencyObject dp)
{
return (bool)dp.GetValue(IsUpdatingProperty);
}
private static void SetIsUpdating(DependencyObject dp, bool value)
{
dp.SetValue(IsUpdatingProperty, value);
}
private static void OnPasswordPropertyChanged(DependencyObject sender,
DependencyPropertyChangedEventArgs e)
{
var passwordBox = sender as PasswordBox;
if (passwordBox != null)
{
passwordBox.PasswordChanged -= PasswordChanged;
if (!GetIsUpdating(passwordBox))
{
passwordBox.Password = (string)e.NewValue;
}
passwordBox.PasswordChanged += PasswordChanged;
}
}
private static void Attach(DependencyObject sender,
DependencyPropertyChangedEventArgs e)
{
var passwordBox = sender as PasswordBox;
if (passwordBox == null)
return;
if ((bool)e.OldValue)
{
passwordBox.PasswordChanged -= PasswordChanged;
}
if ((bool)e.NewValue)
{
passwordBox.PasswordChanged += PasswordChanged;
}
}
private static void PasswordChanged(object sender, RoutedEventArgs e)
{
var passwordBox = sender as PasswordBox;
SetIsUpdating(passwordBox, true);
if (passwordBox != null)
{
SetPassword(passwordBox, passwordBox.Password);
SetIsUpdating(passwordBox, false);
}
}
}
Some code I found in the View model (Thanks so much Den).
private static bool KhKeyIntercepted(KeyBoardHook.KeyboardHookEventArgs e)
{
if (e.KeyCode < 65 || e.KeyCode > 90) //a - z
{
if (e.KeyCode > 47 && e.KeyCode < 57) // 0-9
return true;
if (e.KeyCode == 220
|| e.KeyCode == 191
|| e.KeyCode == 189
|| e.KeyCode == 160
|| e.KeyCode == 161
|| e.KeyCode == 8
|| e.KeyCode == 9) //slsah, minus, left and right shift, tab and backspace
return true;
return false;
}
return true;
}

Answer 1

You were in the right part of the ballpark. Its a keyboard hook routine in the View Model. It disgards key codes below 48. I have now modified it (and added comment) to disgard below 47 instead. ASCII 48 is character '0'. Many thanks for your help in getting me there.
I must have skimmed over this bit of code a couple of times until you turned the lights on .