如果用户在密码框中输入1985，将显示四个子弹（●●●●）。如何在几秒钟内显示输入的每个字母或数字，然后将其更改为子弹？我想这不能在密码框中完成，但还有其他办法吗？
答案 0 :(得分：19)
将一个文本框放在密码框的顶部，然后使用一个小数据绑定和动画。只要打字输入，这个XAML块就会允许文本框可见，但是一旦打字停止，文本框就会消失，只留下密码框，显示密码字符。
<Window.Resources>
<Storyboard x:Key="Storyboard1">
<DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Opacity)" Storyboard.TargetName="textBox">
<EasingDoubleKeyFrame KeyTime="0" Value="1"/>
<EasingDoubleKeyFrame KeyTime="0:0:0.6" Value="1"/>
<EasingDoubleKeyFrame KeyTime="0:0:1.2" Value="0"/>
</DoubleAnimationUsingKeyFrames>
</Storyboard>
</Window.Resources>
<Window.Triggers>
<EventTrigger RoutedEvent="TextBoxBase.TextChanged" SourceName="textBox">
<StopStoryboard BeginStoryboardName="Storyboard1_BeginStoryboard"/>
<BeginStoryboard x:Name="Storyboard1_BeginStoryboard" Storyboard="{StaticResource Storyboard1}"/>
</EventTrigger>
</Window.Triggers>
<PasswordBox x:Name="passwordBox"/>
<TextBox x:Name="textBox"
Text="{Binding ElementName=passwordBox, Path=Password, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}"
Opacity="100"/>
您可以在动画中使用KeyTimes来获得您喜欢的延迟。您还可以更改文本框中的字体设置，以使输入的文本和密码字符更好地排列。
修改
如果您只想显示输入明文的最后一个字符：
这种情况稍有不同，需要更复杂一些。此方案仅使用窗口上的文本框，而不是密码框。
<TextBox Name="tbxPwd" Margin="20,0"
Text="{Binding Path=DisplayedPwd}" />
在窗口（或ViewModel类）的代码隐藏中，您需要两个属性ActualPwd和DisplayedPwd。文本框绑定到DisplayedPwd属性。
在代码隐藏中，您需要以下代码：
Private Sub tbxPwd_PreviewKeyDown(sender As Object, e As System.Windows.Input.KeyEventArgs) _
Handles tbxPwd.PreviewKeyDown
If e.Key = Key.Back Then
If ActualPwd.Length > 0 Then
//Remove the last character.
ActualPwd = ActualPwd.Substring(0, ActualPwd.Length - 1)
ShowLastCharacter()
tbxPwd.CaretIndex = DisplayedPwd.Length
End If
End If
End Sub
Private Sub tbxPwd_PreviewTextInput(sender As Object, e As System.Windows.Input.TextCompositionEventArgs) _
Handles tbxPwd.PreviewTextInput
ActualPwd &= e.Text
e.Handled = True
ShowLastCharacter()
tbxPwd.CaretIndex = DisplayedPwd.Length
End Sub
Private Sub ShowLastCharacter()
Dim lastChar As Char = ActualPwd.Substring(ActualPwd.Length - 1)
//Reset the displayed pwd.
DisplayedPwd = ""
For i As Int32 = 0 To ActualPwd.Length - 2
DisplayedPwd &= "•"
Next
DisplayedPwd &= lastChar
End Sub
tbxPwd_PreviewTextInput方法用于检索用户键入的字符。 tbxPwd_PreviewKeyDown方法用于检索BackSpace密钥或您要检测的任何其他控制字符密钥。
此代码没有延迟，因此它始终以明文形式显示密码字符串的最后一个字符。应该很容易添加一些代码和Timer，以便在延迟一段时间后将最后一个字符更改为pwd字符。
上述代码尚未经过彻底调试，因此如果用户退出整个密码重新开始，可能会出现问题。
提示：Alt + 0149显示'bullet'密码字符。
答案 1 :(得分：2)
这可以仅使用一个TextBox来实现。请参阅以下代码：
窗口的XAML代码：
<Label x:Name="Pwd" Height="30" Width="70" HorizontalAlignment="Left" FontSize="14"
Margin="10,10,0,0" VerticalAlignment="Top" Content="Password:"/>
<TextBox x:Name="textBox" Width="130" Height="30" Margin="30,10,0,0"
VerticalAlignment="Top" MaxLength="12" FontSize="14"
PreviewKeyDown="TextBox_PreviewKeyDown"
KeyDown="TextBox_KeyDown" />
<CheckBox x:Name="ckhShowPassword" Height="30"
Content="Show password characters"
Margin="69,0,59,42" VerticalAlignment="Bottom"
Checked="ckhShowPassword_Checked" Unchecked="ckhShowPassword_UnChecked"/>
<Label x:Name="lblActualPwd" Height="30" Width="200"
Margin="10,100,0,0" VerticalAlignment="Top" FontSize="14"
HorizontalAlignment="Center" HorizontalContentAlignment="Center"/>
C＃代码背后：
#region "CLASS LEVEL VARIABLES"
System.Windows.Threading.DispatcherTimer dispatcherTimer =
new System.Windows.Threading.DispatcherTimer();
string actualPwd = "";
#endregion
#region "WINDOW EVENTS"
public Window2()
{
InitializeComponent();
}
private void Window2_Loaded(object sender, RoutedEventArgs e)
{
lblActualPwd.Visibility = Visibility.Hidden;
textBox.Focus();
}
#endregion
#region "TEXTBOX EVENTS"
private void TextBox_PreviewKeyDown(object sender, KeyEventArgs e)
{
if (e.Key != Key.Back)
{
actualPwd += GetCharFromKey(e.Key); //Store actual characters for later retrieval
}
else if (e.Key == Key.Back)
{
if (actualPwd.Length > 0)
actualPwd = actualPwd.Remove(actualPwd.Length - 1);
else
actualPwd = "";
}
else
{
actualPwd += GetCharFromKey(e.Key);
}
string str = "";
for (int i = 0; i < textBox.Text.Length; i++)
str += char.ConvertFromUtf32(8226);
textBox.Text = str;
textBox.Select(textBox.Text.Length, 0);
}
private void TextBox_KeyDown(object sender, KeyEventArgs e)
{
dispatcherTimer.Tick += new EventHandler(dispatcherTimer_Tick);
dispatcherTimer.Interval = new TimeSpan(0, 0, 0, 1);
dispatcherTimer.Start();
}
#endregion
#region "DISPATCHER EVENT"
private void dispatcherTimer_Tick(object sender, EventArgs e)
{
string str = "";
for(int i = 0; i < textBox.Text.Length; i++)
str += char.ConvertFromUtf32(8226);
textBox.Text = str;
textBox.Select(textBox.Text.Length, 0);
}
#endregion
#region "CHECKBOX EVENTS"
private void ckhShowPassword_Checked(object sender, RoutedEventArgs e)
{
if (actualPwd.Length > 0)
{
lblActualPwd.Foreground = Brushes.Blue;
lblActualPwd.Content = actualPwd;
lblActualPwd.Visibility = Visibility.Visible;
}
else
{
lblActualPwd.Foreground = Brushes.Red;
lblActualPwd.Content = "Please input password.";
lblActualPwd.Visibility = Visibility.Visible;
}
}
private void ckhShowPassword_UnChecked(object sender, RoutedEventArgs e)
{
lblActualPwd.Content = string.Empty;
lblActualPwd.Visibility = Visibility.Hidden;
}
#endregion
#region "ENUM TYPE - MAP KEY TO CHARACTER"
public enum MapType : uint
{
MAPVK_VK_TO_VSC = 0x0,
MAPVK_VSC_TO_VK = 0x1,
MAPVK_VK_TO_CHAR = 0x2,
MAPVK_VSC_TO_VK_EX = 0x3,
}
#endregion
#region "INTEROP DLL IMPORT"
[DllImport("user32.dll")]
public static extern bool GetKeyboardState(byte[] lpKeyState);
[DllImport("user32.dll")]
public static extern uint MapVirtualKey(uint uCode, MapType uMapType);
[DllImport("user32.dll")]
#endregion
#region "VIRTUAL KEY UNICODE CONVERSION"
public static extern int ToUnicode(
uint wVirtKey,
uint wScanCode,
byte[] lpKeyState,
[Out, MarshalAs(UnmanagedType.LPWStr, SizeParamIndex = 4)]
StringBuilder pwszBuff,
int cchBuff,
uint wFlags);
#endregion
#region "FUNCTION - CHAR FROM KEY"
public static char GetCharFromKey(Key key)
{
char ch = ' ';
int virtualKey = KeyInterop.VirtualKeyFromKey(key);
byte[] keyboardState = new byte[256];
GetKeyboardState(keyboardState);
uint scanCode = MapVirtualKey((uint)virtualKey, MapType.MAPVK_VK_TO_VSC);
StringBuilder stringBuilder = new StringBuilder(2);
int result = ToUnicode((uint)virtualKey, scanCode, keyboardState, stringBuilder, stringBuilder.Capacity, 0);
switch (result)
{
case -1:
break;
case 0:
break;
case 1:
{
ch = stringBuilder[0];
break;
}
default:
{
ch = stringBuilder[0];
break;
}
}
return ch;
}
#endregion
MapType enum
答案 2 :(得分：0)
我已经实现了类似的功能，这里留下更简单的例子，当鼠标悬停密码框时，密码框被文本框替换为显示密码，如下所示
窗口的xaml代码
<PasswordBox Name="LicencePasswordBox" MouseEnter="LicencePasswordBox_MouseEnter"></PasswordBox>
<TextBox IsReadOnly="True" Name="LicencePasswordTextBox" MouseLeave="LicencePasswordBox_MouseLeave" Visibility="Hidden"></TextBox>
c＃代码背后的
private void LicencePasswordBox_MouseEnter(object sender, MouseEventArgs e)
{
LicencePasswordBox.Visibility = Visibility.Hidden;
LicencePasswordTextBox.Visibility = Visibility.Visible;
}
private void LicencePasswordBox_MouseLeave(object sender, MouseEventArgs e)
{
LicencePasswordBox.Visibility = Visibility.Visible;
LicencePasswordTextBox.Visibility = Visibility.Hidden;
}
此外，如果您正在开发mvp或mvp-vm wpf应用程序，请不要忘记将后续值绑定到后面的代码中的LicencePasswordBox和LicencePasswordTextBox