다양한 솔루션을 살펴 보는 데 많은 시간을 보냈습니다. 나는 데코레이터 아이디어를 좋아하지 않았고, 행동은 유효성 검사 UI를 뒤섞 고 코드 뒤에 ... 정말?
가장 좋은 방법은 사용자 정의 첨부 속성을 유지하고 SecureString뷰 모델에서 속성에 바인딩하는 것 입니다. 최대한 오래 보관하십시오. 일반 비밀번호에 빠르게 액세스해야 할 때마다 아래 코드를 사용하여 임시로 안전하지 않은 문자열로 변환하십시오.
namespace Namespace.Extensions
{
using System;
using System.Runtime.InteropServices;
using System.Security;
/// <summary>
/// Provides unsafe temporary operations on secured strings.
/// </summary>
[SuppressUnmanagedCodeSecurity]
public static class SecureStringExtensions
{
/// <summary>
/// Converts a secured string to an unsecured string.
/// </summary>
public static string ToUnsecuredString(this SecureString secureString)
{
// copy&paste from the internal System.Net.UnsafeNclNativeMethods
IntPtr bstrPtr = IntPtr.Zero;
if (secureString != null)
{
if (secureString.Length != 0)
{
try
{
bstrPtr = Marshal.SecureStringToBSTR(secureString);
return Marshal.PtrToStringBSTR(bstrPtr);
}
finally
{
if (bstrPtr != IntPtr.Zero)
Marshal.ZeroFreeBSTR(bstrPtr);
}
}
}
return string.Empty;
}
/// <summary>
/// Copies the existing instance of a secure string into the destination, clearing the destination beforehand.
/// </summary>
public static void CopyInto(this SecureString source, SecureString destination)
{
destination.Clear();
foreach (var chr in source.ToUnsecuredString())
{
destination.AppendChar(chr);
}
}
/// <summary>
/// Converts an unsecured string to a secured string.
/// </summary>
public static SecureString ToSecuredString(this string plainString)
{
if (string.IsNullOrEmpty(plainString))
{
return new SecureString();
}
SecureString secure = new SecureString();
foreach (char c in plainString)
{
secure.AppendChar(c);
}
return secure;
}
}
}
GC가 UI 요소를 수집 할 수 있도록하십시오. 따라서의 PasswordChanged이벤트에 정적 이벤트 핸들러를 사용해야한다는 충동에 저항 하십시오 PasswordBox. 또한 컨트롤 SecurePassword을 설정하기 위해 속성을 사용할 때 컨트롤이 UI를 업데이트하지 않는 예외를 발견했습니다 Password. 비밀번호를 대신 복사하는 이유 입니다.
namespace Namespace.Controls
{
using System.Security;
using System.Windows;
using System.Windows.Controls;
using Namespace.Extensions;
/// <summary>
/// Creates a bindable attached property for the <see cref="PasswordBox.SecurePassword"/> property.
/// </summary>
public static class PasswordBoxHelper
{
// an attached behavior won't work due to view model validation not picking up the right control to adorn
public static readonly DependencyProperty SecurePasswordBindingProperty = DependencyProperty.RegisterAttached(
"SecurePassword",
typeof(SecureString),
typeof(PasswordBoxHelper),
new FrameworkPropertyMetadata(new SecureString(),FrameworkPropertyMetadataOptions.BindsTwoWayByDefault, AttachedPropertyValueChanged)
);
private static readonly DependencyProperty _passwordBindingMarshallerProperty = DependencyProperty.RegisterAttached(
"PasswordBindingMarshaller",
typeof(PasswordBindingMarshaller),
typeof(PasswordBoxHelper),
new PropertyMetadata()
);
public static void SetSecurePassword(PasswordBox element, SecureString secureString)
{
element.SetValue(SecurePasswordBindingProperty, secureString);
}
public static SecureString GetSecurePassword(PasswordBox element)
{
return element.GetValue(SecurePasswordBindingProperty) as SecureString;
}
private static void AttachedPropertyValueChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
// we'll need to hook up to one of the element's events
// in order to allow the GC to collect the control, we'll wrap the event handler inside an object living in an attached property
// don't be tempted to use the Unloaded event as that will be fired even when the control is still alive and well (e.g. switching tabs in a tab control)
var passwordBox = (PasswordBox)d;
var bindingMarshaller = passwordBox.GetValue(_passwordBindingMarshallerProperty) as PasswordBindingMarshaller;
if (bindingMarshaller == null)
{
bindingMarshaller = new PasswordBindingMarshaller(passwordBox);
passwordBox.SetValue(_passwordBindingMarshallerProperty, bindingMarshaller);
}
bindingMarshaller.UpdatePasswordBox(e.NewValue as SecureString);
}
/// <summary>
/// Encapsulated event logic
/// </summary>
private class PasswordBindingMarshaller
{
private readonly PasswordBox _passwordBox;
private bool _isMarshalling;
public PasswordBindingMarshaller(PasswordBox passwordBox)
{
_passwordBox = passwordBox;
_passwordBox.PasswordChanged += this.PasswordBoxPasswordChanged;
}
public void UpdatePasswordBox(SecureString newPassword)
{
if (_isMarshalling)
{
return;
}
_isMarshalling = true;
try
{
// setting up the SecuredPassword won't trigger a visual update so we'll have to use the Password property
_passwordBox.Password = newPassword.ToUnsecuredString();
// you may try the statement below, however the benefits are minimal security wise (you still have to extract the unsecured password for copying)
//newPassword.CopyInto(_passwordBox.SecurePassword);
}
finally
{
_isMarshalling = false;
}
}
private void PasswordBoxPasswordChanged(object sender, RoutedEventArgs e)
{
// copy the password into the attached property
if (_isMarshalling)
{
return;
}
_isMarshalling = true;
try
{
SetSecurePassword(_passwordBox, _passwordBox.SecurePassword.Copy());
}
finally
{
_isMarshalling = false;
}
}
}
}
}
그리고 XAML 사용법 :
<PasswordBox controls:PasswordBoxHelper.SecurePassword="{Binding LogonPassword, UpdateSourceTrigger=PropertyChanged, ValidatesOnDataErrors=True}">
뷰 모델의 내 속성은 다음과 같습니다.
[RequiredSecureString]
public SecureString LogonPassword
{
get
{
return _logonPassword;
}
set
{
_logonPassword = value;
NotifyPropertyChanged(nameof(LogonPassword));
}
}
는 RequiredSecureString다음과 같은 논리가 단순한 사용자 정의 유효성 검사기입니다 :
[AttributeUsage(AttributeTargets.Property | AttributeTargets.Field, AllowMultiple = true)]
public class RequiredSecureStringAttribute:ValidationAttribute
{
public RequiredSecureStringAttribute()
:base("Field is required")
{
}
public override bool IsValid(object value)
{
return (value as SecureString)?.Length > 0;
}
}
여기 있습니다. 완벽하고 테스트 된 순수한 MVVM 솔루션.