1，效果

 

2，代码：

        WPF的PasswordBox不能像Winform中的PasswordBox那样，通过PasswordBox.PasswordChar=(char)0显示明文。所以这里使用无外观控件构筑掩码明文切换。

无外观控件遵守Themes/Generic.xaml文件配置.

<ResourceDictionary
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:local="clr-namespace:StudentInfoManagerWPF">


    <Style TargetType="{x:Type local:PasswordBoxExt}">
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type local:PasswordBoxExt}">
                    <Grid>
                        <PasswordBox  x:Name="Part_Pwd"  VerticalContentAlignment="Center" Padding="0,0,30,0"  PasswordChar="{TemplateBinding PasswordChar}"></PasswordBox>
                        <TextBox x:Name="Part_TxtBox" VerticalContentAlignment="Center" Padding="0,0,30,0" Visibility="Collapsed" Text="{Binding RelativeSource={RelativeSource  Mode=FindAncestor,   AncestorType=local:PasswordBoxExt, AncestorLevel=1}, Path=Password}"></TextBox>

                        <ToggleButton x:Name="Part_Toggle"  HorizontalAlignment="Right" MaxWidth="30" >
                            <ToggleButton.Template>
                                <ControlTemplate TargetType="ToggleButton">
                                    <Grid>
                                        <Image x:Name="Part_ImgShow" Source="/icon/1.png" Visibility="Collapsed"></Image>
                                        <Image x:Name="Part_ImgHide" Source="/Icon/2.png" Visibility="Visible"></Image>
                                    </Grid>
                                    <ControlTemplate.Triggers >
                                        <Trigger Property="IsChecked" Value="true">
                                            <Setter Property="Visibility" Value="Visible" TargetName="Part_ImgShow"></Setter>
                                            <Setter Property="Visibility" Value="Collapsed" TargetName="Part_ImgHide"></Setter>
                                        </Trigger>
                                    </ControlTemplate.Triggers>
                                </ControlTemplate>
                            </ToggleButton.Template>
                        </ToggleButton>
                    </Grid>
                    <ControlTemplate.Triggers>
                        <Trigger SourceName="Part_Toggle" Property="IsChecked" Value="true">
                            <Setter TargetName="Part_TxtBox" Property="Visibility" Value="Visible"></Setter>
                        </Trigger>
                        
                    </ControlTemplate.Triggers>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</ResourceDictionary>

public class PasswordBoxExt : Control
    {
        public static readonly DependencyProperty PasswordProperty;
        public static readonly DependencyProperty PasswordCharProperty;
        PasswordBox passwordBox;
        static PasswordBoxExt()
        {
            DefaultStyleKeyProperty.OverrideMetadata(typeof(PasswordBoxExt), new FrameworkPropertyMetadata(typeof(PasswordBoxExt)));
            PasswordProperty = DependencyProperty.Register("Password", typeof(string), typeof(PasswordBoxExt),new PropertyMetadata(new PropertyChangedCallback(PasswordPropertyChanged)));
            PasswordCharProperty = DependencyProperty.Register("PasswordChar", typeof(char), typeof(PasswordBoxExt), new PropertyMetadata('*'));
        }

        private static void PasswordPropertyChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
        {
            //如此每次变化均导致passwordbox被重新覆盖新值，致使光标每次置于字符串首位而不是字符串末尾
           //if( (d as PasswordBoxExt).passwordBox != null)
           // {
           //     (d as PasswordBoxExt).passwordBox.Password = e.NewValue.ToString();
           // }
            
        }

        /// <summary>
        /// 密码
        /// </summary>
        public string Password
        {
            get
            {
                return (string)GetValue(PasswordProperty);
            }
            set
            {
                SetValue(PasswordProperty, value);
            }
        }
        /// <summary>
        /// 掩码字符
        /// </summary>
        public char PasswordChar
        {
            get
            {
               return (char)GetValue(PasswordCharProperty);
            }
            set
            {
                SetValue(PasswordCharProperty, value);
            }
        }

     

        public override void OnApplyTemplate()
        {
            base.OnApplyTemplate();
          passwordBox=  this.GetTemplateChild("Part_Pwd") as PasswordBox;
            ToggleButton btn = this.GetTemplateChild("Part_Toggle") as ToggleButton;
            if (passwordBox != null)
            {
                passwordBox.PasswordChanged += Pwdbox_PasswordChanged;
            }
            if (btn != null)
            {
                btn.Click += Btn_Click;
            }
        }

        private void Btn_Click(object sender, RoutedEventArgs e)
        {
           if((sender as ToggleButton).IsChecked == false)
            {
                passwordBox.Password = Password;
            }
        }

        private void Pwdbox_PasswordChanged(object sender, RoutedEventArgs e)
        {
           if(sender is PasswordBox)
            {
                Password = (sender as PasswordBox).Password;
            }
        }
    }

添加自定义控件

<DockPanel  Grid.Row="2" Grid.Column="1"  VerticalAlignment="Center">
            <TextBlock Text="密码:"  DockPanel.Dock="Left"   FontSize="16"></TextBlock>
            <local:PasswordBoxExt x:Name="pwd01" PasswordChar="#" DockPanel.Dock="Right"  MinHeight="30" Margin="10,0,0,0"></local:PasswordBoxExt>
        </DockPanel>