SpeedportHybridControl.Implementations/PasswordHelper.cs

   1 using System;
   2 using System.Windows;
   3 using System.Windows.Controls;
   4 using System.Windows.Data;
   5
   6 namespace SpeedportHybridControl.Implementations
   7 {
   8
   9     // http://blog.functionalfun.net/2008/06/wpf-passwordbox-and-data-binding.html
  10     public static class PasswordHelper
  11     {
  12         public static readonly DependencyProperty BoundPassword =
  13             DependencyProperty.RegisterAttached("BoundPassword", typeof(string), typeof(PasswordHelper), new PropertyMetadata(string.Empty, OnBoundPasswordChanged));
  14
  15         public static readonly DependencyProperty BindPassword = DependencyProperty.RegisterAttached(
  16             "BindPassword", typeof(bool), typeof(PasswordHelper), new PropertyMetadata(false, OnBindPasswordChanged));
  17
  18         private static readonly DependencyProperty UpdatingPassword =
  19             DependencyProperty.RegisterAttached("UpdatingPassword", typeof(bool), typeof(PasswordHelper), new PropertyMetadata(false));
  20
  21         private static void OnBoundPasswordChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
  22         {
  23             PasswordBox box = d as PasswordBox;
  24
  25             // only handle this event when the property is attached to a PasswordBox
  26             // and when the BindPassword attached property has been set to true
  27             if (d == null || !GetBindPassword(d))
  28             {
  29                 return;
  30             }
  31
  32             // avoid recursive updating by ignoring the box's changed event
  33             box.PasswordChanged -= HandlePasswordChanged;
  34
  35             string newPassword = (string)e.NewValue;
  36
  37             if (!GetUpdatingPassword(box))
  38             {
  39                 box.Password = newPassword;
  40             }
  41
  42             box.PasswordChanged += HandlePasswordChanged;
  43         }
  44
  45         private static void OnBindPasswordChanged(DependencyObject dp, DependencyPropertyChangedEventArgs e)
  46         {
  47             // when the BindPassword attached property is set on a PasswordBox,
  48             // start listening to its PasswordChanged event
  49
  50             PasswordBox box = dp as PasswordBox;
  51
  52             if (box == null)
  53             {
  54                 return;
  55             }
  56
  57             bool wasBound = (bool)(e.OldValue);
  58             bool needToBind = (bool)(e.NewValue);
  59
  60             if (wasBound)
  61             {
  62                 box.PasswordChanged -= HandlePasswordChanged;
  63             }
  64
  65             if (needToBind)
  66             {
  67                 box.PasswordChanged += HandlePasswordChanged;
  68             }
  69         }
  70
  71         private static void HandlePasswordChanged(object sender, RoutedEventArgs e)
  72         {
  73             PasswordBox box = sender as PasswordBox;
  74
  75             // set a flag to indicate that we're updating the password
  76             SetUpdatingPassword(box, true);
  77             // push the new password into the BoundPassword property
  78             SetBoundPassword(box, box.Password);
  79             SetUpdatingPassword(box, false);
  80         }
  81
  82         public static void SetBindPassword(DependencyObject dp, bool value)
  83         {
  84             dp.SetValue(BindPassword, value);
  85         }
  86
  87         public static bool GetBindPassword(DependencyObject dp)
  88         {
  89             return (bool)dp.GetValue(BindPassword);
  90         }
  91
  92         public static string GetBoundPassword(DependencyObject dp)
  93         {
  94             return (string)dp.GetValue(BoundPassword);
  95         }
  96
  97         public static void SetBoundPassword(DependencyObject dp, string value)
  98         {
  99             dp.SetValue(BoundPassword, value);
 100         }
 101
 102         private static bool GetUpdatingPassword(DependencyObject dp)
 103         {
 104             return (bool)dp.GetValue(UpdatingPassword);
 105         }
 106
 107         private static void SetUpdatingPassword(DependencyObject dp, bool value)
 108         {
 109             dp.SetValue(UpdatingPassword, value);
 110         }
 111     }
 112 }