Add PasswordBoxAttachedProperty

davideCappe · May 10, 2024 · 39b8a00 · 39b8a00
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diff --git a/README.md b/README.md
@@ -2,14 +2,28 @@
 
 [![Lint Code Base](https://github.com/davidecappe/CodeSculpt/actions/workflows/linter.yml/badge.svg)](https://github.com/davidecappe/CodeSculpt/actions/workflows/linter.yml)
 [![CodeQL](https://github.com/davidecappe/CodeSculpt/actions/workflows/codeql.yml/badge.svg)](https://github.com/davidecappe/CodeSculpt/actions/workflows/codeql.yml)
-[![NuGet](https://img.shields.io/nuget/v/CodeSculpt.svg?style=flat-square)](https://www.nuget.org/packages/CodeSculpt)
-[![Nuget](https://img.shields.io/nuget/dt/CodeSculpt)](https://www.nuget.org/packages/CodeSculpt)
 [![License: MIT](https://img.shields.io/badge/License-MIT-yellow.svg)](https://github.com/davidecappe/CodeSculpt/blob/master/LICENSE)
 
 Collection of helper methods and classes
 
+## Core library
+
+[![NuGet](https://img.shields.io/nuget/v/CodeSculpt.svg?style=flat-square)](https://www.nuget.org/packages/CodeSculpt)
+[![Nuget](https://img.shields.io/nuget/dt/CodeSculpt)](https://www.nuget.org/packages/CodeSculpt)
+
 **Installation**
 
 The library is available on [NuGet](https://www.nuget.org/packages/CodeSculpt). Just search *CodeSculpt* in the **Package Manager GUI** or run the following command in the **Package Manager Console**:
 
-    Install-Package CodeSculpt
+    Install-Package CodeSculpt
+
+## Wpf helper library
+
+[![NuGet](https://img.shields.io/nuget/v/CodeSculpt.Wpf.svg?style=flat-square)](https://www.nuget.org/packages/CodeSculpt.Wpf)
+[![Nuget](https://img.shields.io/nuget/dt/CodeSculpt.Wpf)](https://www.nuget.org/packages/CodeSculpt.Wpf)
+
+**Installation**
+
+The library is available on [NuGet](https://www.nuget.org/packages/CodeSculpt.Wpf). Just search *CodeSculpt* in the **Package Manager GUI** or run the following command in the **Package Manager Console**:
+
+    Install-Package CodeSculpt.Wpf
diff --git a/src/CodeSculpt.Wpf/AttachedProperties/PasswordBoxAssistant.cs b/src/CodeSculpt.Wpf/AttachedProperties/PasswordBoxAssistant.cs
@@ -0,0 +1,80 @@
+using System.Windows;
+using System.Windows.Controls;
+
+namespace CodeSculpt.Wpf.AttachedProperties;
+public static class PasswordBoxAssistant
+{
+    public static readonly DependencyProperty BoundPassword = DependencyProperty.RegisterAttached("BoundPassword", typeof(string), typeof(PasswordBoxAssistant), new PropertyMetadata(string.Empty, OnBoundPasswordChanged));
+    public static readonly DependencyProperty BindPassword = DependencyProperty.RegisterAttached("BindPassword ", typeof(bool), typeof(PasswordBoxAssistant), new PropertyMetadata(false, OnBindPasswordChanged));
+    public static readonly DependencyProperty UpdatingPassword = DependencyProperty.RegisterAttached("UpdatingPassword", typeof(bool), typeof(PasswordBoxAssistant), new PropertyMetadata(false));
+
+    private static void OnBoundPasswordChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
+    {
+        var box = d as PasswordBox;
+
+        // only handle this event when the property is attached to a PasswordBox
+        // and when the BindPassword attached property has been set to true
+        if (d == null || !GetBindPassword(d))
+        {
+            return;
+        }
+
+        // avoid recursive updating by ignoring the box's changed event
+        box!.PasswordChanged -= HandlePasswordChanged;
+
+        var newPassword = (string)e.NewValue;
+
+        if (!GetUpdatingPassword(box))
+        {
+            box.Password = newPassword;
+        }
+
+        box.PasswordChanged += HandlePasswordChanged;
+    }
+
+    private static void OnBindPasswordChanged(DependencyObject dp, DependencyPropertyChangedEventArgs e)
+    {
+        // when the BindPassword attached property is set on a PasswordBox,
+        // start listening to its PasswordChanged event
+
+        if (dp is not PasswordBox box)
+        {
+            return;
+        }
+
+        var wasBound = (bool)e.OldValue;
+        var needToBind = (bool)e.NewValue;
+
+        if (wasBound)
+        {
+            box.PasswordChanged -= HandlePasswordChanged;
+        }
+
+        if (needToBind)
+        {
+            box.PasswordChanged += HandlePasswordChanged;
+        }
+    }
+    private static void HandlePasswordChanged(object sender, RoutedEventArgs e)
+    {
+        var box = sender as PasswordBox;
+
+        // set a flag to indicate that we're updating the password
+        SetUpdatingPassword(box!, true);
+        // push the new password into the BoundPassword property
+        SetBoundPassword(box!, box!.Password);
+        SetUpdatingPassword(box, false);
+    }
+
+    public static void SetBindPassword(DependencyObject dp, bool value) => dp.SetValue(BindPassword, value);
+
+    public static bool GetBindPassword(DependencyObject dp) => (bool)dp.GetValue(BindPassword);
+
+    public static string GetBoundPassword(DependencyObject dp) => (string)dp.GetValue(BoundPassword);
+
+    public static void SetBoundPassword(DependencyObject dp, string value) => dp.SetValue(BoundPassword, value);
+
+    private static bool GetUpdatingPassword(DependencyObject dp) => (bool)dp.GetValue(UpdatingPassword);
+
+    private static void SetUpdatingPassword(DependencyObject dp, bool value) => dp.SetValue(UpdatingPassword, value);
+}