如何在MVVM绑定到密码盒

我遇到了绑定到密码盒的问题。这似乎是一个安全风险，但我正在使用MVVM模式，所以我希望绕过这个。我在这里发现了一些有趣的代码(有人使用过这个或类似的代码吗?)

http://www.wpftutorial.net/PasswordBox.html

从技术上讲，它看起来很棒，但我不确定如何检索密码。

我基本上有属性在我的LoginViewModel用户名和密码。用户名是好的，正在工作，因为它是一个文本框。

我使用上面的代码，并输入这个

<PasswordBox ff:PasswordHelper.Attach="True"
    ff:PasswordHelper.Password="{Binding Path=Password}" Width="130"/>

当我有PasswordBox作为一个文本框和绑定路径=密码，然后在我的LoginViewModel属性更新。

我的代码非常简单，基本上我有一个命令为我的按钮。当我按下它CanLogin被调用，如果它返回真，它调用Login。你可以看到，我检查了我的用户名属性，这很好。

在登录我发送到我的服务的用户名和密码，用户名包含数据从我的视图，但密码是空|空

private DelegateCommand loginCommand;

public string Username { get; set; }
public string Password { get; set; }


public ICommand LoginCommand
{
    get
    {
        if (loginCommand == null)
        {
            loginCommand = new DelegateCommand(
                Login, CanLogin );
        }
        return loginCommand;
    }
}

private bool CanLogin()
{
    return !string.IsNullOrEmpty(Username);
}

private void Login()
{
    bool result = securityService.IsValidLogin(Username, Password);

    if (result) { }
    else { }
}

这就是我正在做的

<TextBox Text="{Binding Path=Username, UpdateSourceTrigger=PropertyChanged}"
         MinWidth="180" />

<PasswordBox ff:PasswordHelper.Attach="True" 
             ff:PasswordHelper.Password="{Binding Path=Password}" Width="130"/>

我有我的文本框，这是没有问题的，但在我的ViewModel密码是空的。

是我做错了什么还是漏了一步?

我放了一个断点，果然代码进入静态助手类，但它从不更新我的ViewModel中的密码。

当前回答

using System; using System.Windows; using System.Windows.Controls; using Caliburn.Micro; namespace Elections.Server.Handler.ViewModels { public class LoginViewModel : PropertyChangedBase { MainViewModel _mainViewModel; public void SetMain(MainViewModel mainViewModel) { _mainViewModel = mainViewModel; } public void Login(Object password) { var pass = (PasswordBox) password; MessageBox.Show(pass.Password); //_mainViewModel.ScreenView = _mainViewModel.ControlPanelView; //_mainViewModel.TitleWindow = "Panel de Control"; //HandlerBootstrapper.Title(_mainViewModel.TitleWindow); } } }

,简单!

2016-07-28 19:49:03

其他回答

对我来说，这两件事都不对:

实现明文密码属性将PasswordBox作为命令参数发送给ViewModel

像Steve在CO中描述的那样传输SecurePassword (SecureString实例)似乎是可以接受的。我更喜欢行为而不是背后的代码，而且我还需要能够从视图模型重置密码。

Xaml (Password是ViewModel属性):

<PasswordBox>
    <i:Interaction.Behaviors>
        <behaviors:PasswordBinding BoundPassword="{Binding Password, Mode=TwoWay}" />
    </i:Interaction.Behaviors>
</PasswordBox>

行为:

using System.Security;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Interactivity;

namespace Evidence.OutlookIntegration.AddinLogic.Behaviors
{
    /// <summary>
    /// Intermediate class that handles password box binding (which is not possible directly).
    /// </summary>
    public class PasswordBoxBindingBehavior : Behavior<PasswordBox>
    {
        // BoundPassword
        public SecureString BoundPassword { get { return (SecureString)GetValue(BoundPasswordProperty); } set { SetValue(BoundPasswordProperty, value); } }
        public static readonly DependencyProperty BoundPasswordProperty = DependencyProperty.Register("BoundPassword", typeof(SecureString), typeof(PasswordBoxBindingBehavior), new FrameworkPropertyMetadata(OnBoundPasswordChanged));

        protected override void OnAttached()
        {
            this.AssociatedObject.PasswordChanged += AssociatedObjectOnPasswordChanged;
            base.OnAttached();
        }

        /// <summary>
        /// Link up the intermediate SecureString (BoundPassword) to the UI instance
        /// </summary>
        private void AssociatedObjectOnPasswordChanged(object s, RoutedEventArgs e)
        {
            this.BoundPassword = this.AssociatedObject.SecurePassword;
        }

        /// <summary>
        /// Reacts to password reset on viewmodel (ViewModel.Password = new SecureString())
        /// </summary>
        private static void OnBoundPasswordChanged(object s, DependencyPropertyChangedEventArgs e)
        {
            var box = ((PasswordBoxBindingBehavior)s).AssociatedObject;
            if (box != null)
            {
                if (((SecureString)e.NewValue).Length == 0)
                    box.Password = string.Empty;
            }
        }

    }
}

2014-10-07 17:15:10

以下是我的看法:

Using an attached property to bind the password defeats the purpose of securing the password. The Password property of a password box is not bindable for a reason. Passing the password box as command parameter will make the ViewModel aware of the control. This will not work if you plan to make your ViewModel reusable cross platform. Don't make your VM aware of your View or any other controls. I don't think introducing a new property, an interface, subscribing to password changed events or any other complicated things is necessary for a simple task of providing the password.

XAML

<PasswordBox x:Name="pbPassword" />
<Button Content="Login" Command="{Binding LoginCommand}" x:Name="btnLogin"/>

代码背后——使用代码背后并不一定违反MVVM。只要你不把任何业务逻辑放在里面。

btnLogin.CommandParameter = new Func<string>(()=>pbPassword.Password);

ViewModel

LoginCommand = new RelayCommand<Func<string>>(getpwd=> { service.Login(username, getpwd()); });

2018-08-22 14:22:02

对于像我这样的新手，这里有一个完整的工作样本。谢谢Konamiman。

XAML

    <PasswordBox x:Name="textBoxPassword"/>
    <Button x:Name="buttonLogin" Content="Login"
            Command="{Binding PasswordCommand}"
            CommandParameter="{Binding ElementName=textBoxPassword}"/>

ViewModel

public class YourViewModel : ViewModelBase
{
    private ICommand _passwordCommand;
    public ICommand PasswordCommand
    {
        get {
            if (_passwordCommand == null) {
                _passwordCommand = new RelayCommand<object>(PasswordClick);
            }
            return _passwordCommand;
        }
    }

    public YourViewModel()
    {
    }

    private void PasswordClick(object p)
    {
        var password = p as PasswordBox;
        Console.WriteLine("Password is: {0}", password.Password);
    }
}

2018-09-07 10:59:42

这个实现略有不同。通过绑定ViewModel中的属性将PasswordBox传递给View。它不使用任何命令参数。ViewModel对视图保持无知。我有一个VB VS 2010项目，可以从SkyDrive下载。WPF MVVM PassWordBox Example.zip

我在WPF MVVM应用程序中使用PasswordBox的方式非常简单，对我来说工作得很好。

基本上你创建了一个公共只读属性，视图可以绑定到PasswordBox(实际控件):

Private _thePassWordBox As PasswordBox
Public ReadOnly Property ThePassWordBox As PasswordBox
    Get
        If IsNothing(_thePassWordBox) Then _thePassWordBox = New PasswordBox
        Return _thePassWordBox
    End Get
End Property

我使用了一个支持字段来完成属性的自我初始化。

然后从Xaml中绑定ContentControl或Control Container的内容:

 <ContentControl Grid.Column="1" Grid.Row="1" Height="23" Width="120" Content="{Binding Path=ThePassWordBox}" HorizontalAlignment="Center" VerticalAlignment="Center" />

从那里你可以完全控制密码盒。我还使用PasswordAccessor(只是一个字符串的函数)返回密码值时，做登录或任何其他你想要的密码。在这个例子中，我在通用用户对象模型中有一个公共属性。例子:

Public Property PasswordAccessor() As Func(Of String)

在用户对象中，密码字符串属性是只读的，没有任何备份存储。它只是从PasswordBox返回Password。例子:

Public ReadOnly Property PassWord As String
    Get
        Return If((PasswordAccessor Is Nothing), String.Empty, PasswordAccessor.Invoke())
    End Get
End Property

然后在ViewModel中，我确保Accessor被创建并设置为PasswordBox。密码属性:

Public Sub New()
    'Sets the Accessor for the Password Property
    SetPasswordAccessor(Function() ThePassWordBox.Password)
End Sub

Friend Sub SetPasswordAccessor(ByVal accessor As Func(Of String))
    If Not IsNothing(VMUser) Then VMUser.PasswordAccessor = accessor
End Sub

当我需要密码字符串说登录，我只是得到用户对象密码属性，真正调用函数抓取密码并返回它，然后实际的密码不存储在用户对象。例如:将在ViewModel中

Private Function LogIn() as Boolean
    'Make call to your Authentication methods and or functions. I usally place that code in the Model
    Return AuthenticationManager.Login(New UserIdentity(User.UserName, User.Password)
End Function

That should do it. The ViewModel doesn't need any knowledge of the View's Controls. The View just binds to the Property in the ViewModel, not any different than the View Binding to an image or other resource. In this case that resource(Property) just happens to be a usercontrol. It allows for testing as the ViewModel creates and owns the Property and the Property is independent of the View. As for security I don't know how good this implementation is. But by using a Function the value is not stored in the Property itself just accessed by the Property.

2011-08-31 06:36:36

正如你所看到的，我绑定到密码，但也许它绑定到静态类..

它是一个附加属性。这种属性可以应用于任何类型的DependencyObject，而不仅仅是声明它的类型。因此，尽管它是在PasswordHelper静态类中声明的，但它还是应用于使用它的PasswordBox。

要使用这个附加属性，你只需要将它绑定到ViewModel中的Password属性:

<PasswordBox w:PasswordHelper.Attach="True" 
         w:PasswordHelper.Password="{Binding Password}"/>

2009-09-27 16:45:54

如何在MVVM绑定到密码盒

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