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Why is WPF PasswordBox sometimes empty but not others?

I am including an example program: it seems that when pasting into a PasswordBox, typing and tabbing makes PasswordBox empty. But double-clicking in PasswordBox, typing and tabbing is not. Why is this happening?

Edit: I found that this also happens with TextBox, so this is not a bug specific to PasswordBox.

Steps to recreate each scenario:

Disable password

  • Click Create.
  • One click in the name field.
  • Enter something
  • Press the Tab key
  • Enter something
  • Press the Tab key
  • Press the TAB key (yes, the save event is saved twice as much)
  • Enter something
  • Pay attention to dots instead of text - PasswordBox works!
  • Press the Tab key.
  • Amaze your friends when PasswordBox is empty!

Make password DO NOT disappear

  • Click Create.
  • One click in the name field.
  • Enter something
  • Press the Tab key
  • Enter something
  • Double-click in the password field.
  • Enter something
  • Pay attention to dots instead of text - PasswordBox works!
  • Press the Tab key.
  • , .. , PasswordBox ? WTF?

:

using System;
using System.Collections.ObjectModel;
namespace WpfApplication1 {
    public sealed class MyData    {
        private ObservableCollection<MyDataRow> dataList;
        public ObservableCollection<MyDataRow> DataList { get { return dataList; } }
        public MyData() { dataList = new ObservableCollection<MyDataRow>(); }
        public void AddBlankRow() { DataList.Add(new MyDataRow(this)); }
    }
    public sealed class MyDataRow     {
        private readonly MyData myData;
        public MyDataRow(MyData myData) { this.myData = myData; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public string Password { get; set; }
    }
}

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;

namespace WpfApplication1 {
    public partial class MainWindow : Window  {
        private MyData Data { get { return (MyData)DataContext; } }

        public MainWindow() { InitializeComponent(); }

        private void PasswordBox_PasswordChanged(object sender, RoutedEventArgs e)  {
            PasswordBox pb = (PasswordBox)sender;
            if (pb != null) {
                MyDataRow row = pb.DataContext as MyDataRow;
                if (row != null) { row.Password = pb.Password; }
            }
        }

        private void Window_Loaded(object sender, RoutedEventArgs e) { DataContext = new MyData(); }
        private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e) { }
        private void SaveExecute(object sender, ExecutedRoutedEventArgs e) { }
        private void NewExecute(object sender, ExecutedRoutedEventArgs e) { Data.AddBlankRow(); }
        private void CancelExecute(object sender, ExecutedRoutedEventArgs e) { Close(); }
    }
}

<Window x:Class="WpfApplication1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="350" Width="525" Loaded="Window_Loaded" WindowStartupLocation="CenterScreen" Closing="Window_Closing">
    <Window.CommandBindings>
        <CommandBinding Command="Save" Executed="SaveExecute" />
        <CommandBinding Command="New" Executed="NewExecute" />
        <CommandBinding Command="Close" Executed="CancelExecute" />
    </Window.CommandBindings>
    <Grid Margin="0,10,0,0">
        <DataGrid ItemsSource="{Binding DataList}" ColumnWidth="*" Margin="10,0,9,38" HorizontalAlignment="Stretch" 
                  AutoGenerateColumns="False" GridLinesVisibility="Horizontal"
                  HeadersVisibility="Column" HorizontalGridLinesBrush="LightGray" CanUserReorderColumns="False" Background="White" >
            <DataGrid.Columns>
                <DataGridTextColumn Header="First Name"  Binding="{Binding FirstName}"/>
                <DataGridTextColumn Header="Last Name"  Binding="{Binding LastName}"/>
                <DataGridTemplateColumn Header="Password" >
                    <DataGridTemplateColumn.CellTemplate>
                        <DataTemplate>
                            <PasswordBox PasswordChanged="PasswordBox_PasswordChanged"   BorderThickness="0"
                                     Height="23" HorizontalAlignment="Stretch"/>
                        </DataTemplate>
                    </DataGridTemplateColumn.CellTemplate>
                </DataGridTemplateColumn>
            </DataGrid.Columns>
        </DataGrid>
        <Button  
            Content="_New" Command="New"
            Width="75" Height="23" Margin="10,10,10,10"
            HorizontalAlignment="Left" VerticalAlignment="Bottom"/>
        <Button 
            Content="_Save" Command="Save"
            IsDefault="True"
            IsEnabled="True"
            Width="75" Height="23" Margin="10,10,91,10"
            HorizontalAlignment="Right" VerticalAlignment="Bottom" />
        <Button
            Content="Cancel" Command="Close"
            IsEnabled="True"
            Width="75" Height="23" Margin="10,10,10,10"
            HorizontalAlignment="Right" VerticalAlignment="Bottom"/>
    </Grid>
</Window>

CellTemplate EditingCellTemplate, - - - ( elipse). , , PasswordBox , elipse. , , . David Edey DataGrid_PreparingCellForEdit .

.

    <Grid.Resources>
        <DataTemplate x:Key="PasswordTemplate" >
            <Label BorderThickness="0" Height="23" HorizontalAlignment="Stretch" Content="..."/>
        </DataTemplate>
        <DataTemplate x:Key="EditingPasswordTemplate" >
            <PasswordBox PasswordChanged="PasswordBox_PasswordChanged"   BorderThickness="0" 
                                 Height="23" HorizontalAlignment="Stretch" />
        </DataTemplate>
    </Grid.Resources>
+4
1

, : (CellEditingTemplate) (CellTemplate). - , : http://msdn.microsoft.com/en-us/library/system.windows.controls.datagridtemplatecolumn.celltemplate(v=vs.110).aspx

, , PasswordBox Password ( Password ) . ( , , , , , , ), : http://wpftutorial.net/PasswordBox.html - .

, , , , PreparingCellForEdit, <2 >

, :

using System;
using System.Collections.ObjectModel;
namespace WpfApplication1 {
    public sealed class MyData    {
        private ObservableCollection<MyDataRow> dataList;
        public ObservableCollection<MyDataRow> DataList { get { return dataList; } }
        public MyData() { dataList = new ObservableCollection<MyDataRow>(); }
        public void AddBlankRow() { DataList.Add(new MyDataRow(this)); }
    }
    public sealed class MyDataRow     {
        private readonly MyData myData;
        public MyDataRow(MyData myData) { this.myData = myData; }
        public string FirstName { get; set; }
        public string LastName { get; set; }
        public string Password { get; set; }
    }
}

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;
using System.Windows.Media;

namespace WpfApplication1 {
    public partial class MainWindow : Window
    {
        public MainWindow() { InitializeComponent(); }
        private MyData Data { get { return (MyData)DataContext; } }

        void DataGrid_PreparingCellForEdit(object sender, DataGridPreparingCellForEditEventArgs e)
        {
            var inputElement = VisualTreeHelper.GetChild(e.EditingElement, 0) as PasswordBox;
            if (inputElement != null)
            {
                Keyboard.Focus(inputElement);
            }
        }

        private void Window_Loaded(object sender, RoutedEventArgs e) { DataContext = new MyData(); }
        private void Window_Closing(object sender, System.ComponentModel.CancelEventArgs e) { }
        private void SaveExecute(object sender, ExecutedRoutedEventArgs e) { }
        private void NewExecute(object sender, ExecutedRoutedEventArgs e) { Data.AddBlankRow(); }
        private void CancelExecute(object sender, ExecutedRoutedEventArgs e) { Close(); }
    }

xaml:

<Window x:Class="WpfApplication1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:w="clr-namespace:WpfApplication1"
        Title="MainWindow" Height="350" Width="525" Loaded="Window_Loaded" WindowStartupLocation="CenterScreen" Closing="Window_Closing">
    <Window.CommandBindings>
        <CommandBinding Command="Save" Executed="SaveExecute" />
        <CommandBinding Command="New" Executed="NewExecute" />
        <CommandBinding Command="Close" Executed="CancelExecute" />
    </Window.CommandBindings>
    <Grid Margin="0,10,0,0">
        <DataGrid ItemsSource="{Binding DataList, Mode=OneTime}" ColumnWidth="*" Margin="10,0,9,38" HorizontalAlignment="Stretch"
                  AutoGenerateColumns="False" GridLinesVisibility="Horizontal"
                  HeadersVisibility="Column" HorizontalGridLinesBrush="LightGray" CanUserReorderColumns="False" Background="White"
                  PreparingCellForEdit="DataGrid_PreparingCellForEdit">
            <DataGrid.Resources>
                <DataTemplate x:Key="PasswordTemplate">
                    <PasswordBox w:PasswordHelper.Attach="True" w:PasswordHelper.Password="{Binding Password, Mode=TwoWay}" 
                                 BorderThickness="0" Height="23" HorizontalAlignment="Stretch" Width="130" />
                </DataTemplate>
            </DataGrid.Resources>
            <DataGrid.Columns>
                <DataGridTextColumn Header="First Name"  Binding="{Binding FirstName}"/>
                <DataGridTextColumn Header="Last Name"  Binding="{Binding LastName}"/>
                <DataGridTemplateColumn Header="Password" CellTemplate="{StaticResource PasswordTemplate}"
                                        CellEditingTemplate="{StaticResource PasswordTemplate}" />
            </DataGrid.Columns>
        </DataGrid>
        <Button
            Content="_New" Command="New"
            Width="75" Height="23" Margin="10,10,10,10"
            HorizontalAlignment="Left" VerticalAlignment="Bottom"/>
        <Button
            Content="_Save" Command="Save"
            IsDefault="True"
            IsEnabled="True"
            Width="75" Height="23" Margin="10,10,91,10"
            HorizontalAlignment="Right" VerticalAlignment="Bottom" />
        <Button
            Content="Cancel" Command="Close"
            IsEnabled="True"
            Width="75" Height="23" Margin="10,10,10,10"
            HorizontalAlignment="Right" VerticalAlignment="Bottom"/>
    </Grid>
</Window>

PasswordHelper http://wpftutorial.net/PasswordBox.html voila.

+3

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