WPF MVVM密碼框綁定

我目前在WPF應用程序的密碼框中使用以下附加行爲。我可以使用UI設置密碼，我加密這個值並存儲在數據庫中。加載視圖模型並設置綁定到密碼框的SecureString屬性時，密碼字段顯示爲空。（即使密碼已成功加載）。WPF MVVM密碼框綁定

爲了使PasswordBox在ViewModel中設置值時顯示爲填充，我需要更改什麼？

我已經添加了在XAML和ViewModel中使用的代碼。 LoadPassword（）方法返回一個SecureString。

行爲

/// <summary> 
/// Provides additional properties to use against PasswordBox controls. 
/// </summary> 
/// <remarks> 
/// Sometimes controls have properties that don't support binding. PasswordBox is one of these, where Microsoft's implementation does not support binding against the entered 
/// password (for 'security purposes'). 
/// 
/// This class provides an 'attached property' which allows us to bridge the gap between the view and view model. 
/// </remarks> 
public static class Password 
{ 
    #region Dependency properties 

    /// <summary> 
    /// SecurePassword property. 
    /// </summary> 
    public static readonly DependencyProperty SecurePasswordProperty = DependencyProperty.RegisterAttached("SecurePassword", typeof(SecureString), typeof(Password), new FrameworkPropertyMetadata(OnSecurePasswordChanged)); 

    /// <summary> 
    /// HasSecurePassword property. 
    /// </summary> 
    private static readonly DependencyProperty HasSecurePasswordProperty = DependencyProperty.RegisterAttached("HasSecurePassword", typeof(bool), typeof(Password)); 

    #endregion 

    #region Methods 

    /// <summary> 
    /// Sets the value of the SecurePassword property. 
    /// </summary> 
    /// <param name="dependencyObject">The object to set the property for.</param> 
    /// <param name="value">The value to set.</param> 
    public static void SetSecurePassword(DependencyObject dependencyObject, SecureString value) 
    { 
     if (dependencyObject == null) 
      throw new ArgumentNullException(nameof(dependencyObject)); 

     dependencyObject.SetValue(Password.SecurePasswordProperty, value); 
    } 

    /// <summary> 
    /// Gets the value of the SecurePassword property. 
    /// </summary> 
    /// <param name="dependencyObject">The object to get the property for.</param> 
    /// <returns>The current value.</returns> 
    public static SecureString GetSecurePassword(DependencyObject dependencyObject) 
    { 
     if (dependencyObject == null) 
      throw new ArgumentNullException(nameof(dependencyObject)); 

     return (SecureString)dependencyObject.GetValue(Password.SecurePasswordProperty); 
    } 

    #endregion 

    /// <summary> 
    /// Handles the SecurePassword value changing. 
    /// </summary> 
    private static void OnSecurePasswordChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs e) 
    { 
     PasswordBox password = dependencyObject as PasswordBox; 

     bool? isRegistered = (bool?)password?.GetValue(Password.HasSecurePasswordProperty); 
     if (isRegistered == false) 
     { 
      // register with the PasswordBox's PasswordChanged event so that we can keep updated with the latest value entered by the user 
      password.PasswordChanged += (s, ee) => SetSecurePassword(password, password.SecurePassword); 
      password.SetValue(Password.HasSecurePasswordProperty, true); 
     } 
    } 
}

XAML

<PasswordBox Grid.Column="1" Grid.Row="2" behaviours:Password.SecurePassword="{Binding Path=Password, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" Margin="2"/>

視圖模型

public SecureString Password 
{ 
    get { return this._password; } 
    set { base.SetProperty(ref _password, value); } 
} 

public SettingsViewModel() 
{ 
    this.Password = LoadPassword(); 
}

來源

2016-04-21 seanzi

您可以包含屬性的PasswordBox XAML和ViewModel代碼嗎？ –

@GlenThomas我添加了更多的代碼示例，它們顯示了更大的圖片。我原本應該包括他們，對此很抱歉。 – seanzi

你根本無法設置SecurePassword。這是一個只讀屬性。如果你想填寫密碼框，你必須設置不安全字符串Password屬性。

來源

2016-04-22 06:57:19

WPF MVVM密碼框綁定

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