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。
为了在不破坏MVVM的情况下解决OP问题，我将使用自定义值转换器和必须从密码框中检索的值(密码)的包装器。
public interface IWrappedParameter<T>
{
T Value { get; }
}
public class PasswordBoxWrapper : IWrappedParameter<string>
{
private readonly PasswordBox _source;
public string Value
{
get { return _source != null ? _source.Password : string.Empty; }
}
public PasswordBoxWrapper(PasswordBox source)
{
_source = source;
}
}
public class PasswordBoxConverter : IValueConverter
{
public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
{
// Implement type and value check here...
return new PasswordBoxWrapper((PasswordBox)value);
}
public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
{
throw new InvalidOperationException("No conversion.");
}
}
在视图模型中:
public string Username { get; set; }
public ICommand LoginCommand
{
get
{
return new RelayCommand<IWrappedParameter<string>>(password => { Login(Username, password); });
}
}
private void Login(string username, string password)
{
// Perform login here...
}
因为视图模型使用IWrappedParameter<T>，所以它不需要任何关于PasswordBoxWrapper或PasswordBoxConverter的知识。这样您就可以将PasswordBox对象与视图模型隔离开来，并且不会破坏MVVM模式。
在视图中:
<Window.Resources>
<h:PasswordBoxConverter x:Key="PwdConverter" />
</Window.Resources>
...
<PasswordBox Name="PwdBox" />
<Button Content="Login" Command="{Binding LoginCommand}"
CommandParameter="{Binding ElementName=PwdBox, Converter={StaticResource PwdConverter}}" />
我想我应该把我的解决方案放在一起，因为这是一个很常见的问题……拥有大量的选择总是一件好事。
I simply wrapped a PasswordBox in a UserControl and implemented a DependencyProperty to be able to bind. I'm doing everything I can to avoid storing any clear text in the memory, so everything is done through a SecureString and the PasswordBox.Password property. During the foreach loop, each character does get exposed, but it's very brief. Honestly, if you're worried about your WPF application to be compromised from this brief exposure, you've got bigger security issues that should be handled.
这样做的好处是你没有违反任何MVVM规则，即使是“最纯粹的”规则，因为这是一个UserControl，所以它允许有代码隐藏。当你使用它时，你可以在View和ViewModel之间进行纯通信，而你的VideModel不知道View的任何部分或密码的来源。只要确保你在ViewModel中绑定到SecureString。
BindablePasswordBox.xaml
<UserControl x:Class="BK.WPF.CustomControls.BindanblePasswordBox"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
mc:Ignorable="d" d:DesignHeight="22" d:DesignWidth="150">
<PasswordBox x:Name="PswdBox"/>
</UserControl>
BindablePasswordBox.xaml.cs(版本1 -不支持双向绑定)
using System.ComponentModel;
using System.Security;
using System.Windows;
using System.Windows.Controls;
namespace BK.WPF.CustomControls
{
public partial class BindanblePasswordBox : UserControl
{
public static readonly DependencyProperty PasswordProperty =
DependencyProperty.Register("Password", typeof(SecureString), typeof(BindanblePasswordBox));
public SecureString Password
{
get { return (SecureString)GetValue(PasswordProperty); }
set { SetValue(PasswordProperty, value); }
}
public BindanblePasswordBox()
{
InitializeComponent();
PswdBox.PasswordChanged += PswdBox_PasswordChanged;
}
private void PswdBox_PasswordChanged(object sender, RoutedEventArgs e)
{
var secure = new SecureString();
foreach (var c in PswdBox.Password)
{
secure.AppendChar(c);
}
Password = secure;
}
}
}
版本1的用法:
<local:BindanblePasswordBox Width="150" HorizontalAlignment="Center"
VerticalAlignment="Center"
Password="{Binding Password, Mode=OneWayToSource}"/>
BindablePasswordBox.xaml.cs(版本2 -支持双向绑定)
public partial class BindablePasswordBox : UserControl
{
public static readonly DependencyProperty PasswordProperty =
DependencyProperty.Register("Password", typeof(SecureString), typeof(BindablePasswordBox),
new PropertyMetadata(PasswordChanged));
public SecureString Password
{
get { return (SecureString)GetValue(PasswordProperty); }
set { SetValue(PasswordProperty, value); }
}
public BindablePasswordBox()
{
InitializeComponent();
PswdBox.PasswordChanged += PswdBox_PasswordChanged;
}
private void PswdBox_PasswordChanged(object sender, RoutedEventArgs e)
{
var secure = new SecureString();
foreach (var c in PswdBox.Password)
{
secure.AppendChar(c);
}
if (Password != secure)
{
Password = secure;
}
}
private static void PasswordChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
var pswdBox = d as BindablePasswordBox;
if (pswdBox != null && e.NewValue != e.OldValue)
{
var newValue = e.NewValue as SecureString;
if (newValue == null)
{
return;
}
var unmanagedString = IntPtr.Zero;
string newString;
try
{
unmanagedString = Marshal.SecureStringToGlobalAllocUnicode(newValue);
newString = Marshal.PtrToStringUni(unmanagedString);
}
finally
{
Marshal.ZeroFreeGlobalAllocUnicode(unmanagedString);
}
var currentValue = pswdBox.PswdBox.Password;
if (currentValue != newString)
{
pswdBox.PswdBox.Password = newString;
}
}
}
}
版本2的用途:
<local:BindanblePasswordBox Width="150" HorizontalAlignment="Center"
VerticalAlignment="Center"
Password="{Binding Password, Mode=TwoWay}"/>
