如何将NotifyDataErrorInfo传递到自定义TextBox用户控件？

Question

目标

我正在练习如何将

TextBox

与绑定到

Type

属性的不同

Text

一起使用。

有很多线程讨论这个问题。但是，我缺少一些步骤，希望得到一些支持。

输入值必须在特定范围内
仅允许正整数

space

、

backspace

和

delete

击键，以防止

System.Windows.Data Error

设定

使用 .Net 8 的 Wpf 应用程序
MVVM模式；依赖注入
社区工具包.Mvvm
GitHub 上的公共存储库

View包含三个TextBox

控件，它们绑定到

ViewModel的相同属性。 CommunityToolkit.Mvvm

 用于减少样板代码。

    [ObservableProperty]
    [NotifyCanExecuteChangedFor(nameof(SaveDataButtonCommand))]
    [NotifyCanExecuteChangedFor(nameof(DiscardButtonCommand))]
    [NotifyDataErrorInfo]
    [Range(9, 999, ErrorMessage = "Value is out of range")]
    private int _intValue = 0;
    private int _backupIntValue = 0;

Integer TextBox 是具有标准行为的 TextBox
CustomTextBox 是一个 TextBox
```
，其中事件处理程序添加在 
```
HomeView.xaml.cs
中

自定义 IntegerTextBox 是一个名为 IntegerTextBox.xaml

 的自定义用户控件，其中添加了事件处理程序并注册了名为

DependencyProperty

的

Value

。

                <!-- Integer components -->
                <Label Grid.Row="2" Grid.Column="1" Content="Integer TextBox" />
                <TextBox Grid.Row="3" Grid.Column="1"
                         MinWidth="200"
                         Text="{Binding IntValue, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnNotifyDataErrors=True}" />
                <Label Grid.Row="2" Grid.Column="3" Content="Custom TextBox" />
                <TextBox x:Name="CustomTextBox" 
                         Grid.Row="3" Grid.Column="3"
                         HorizontalContentAlignment="Right"
                         MinWidth="200"
                         Text="{Binding IntValue, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnNotifyDataErrors=True}" />
                <Label Grid.Row="2" Grid.Column="5" Content="Custom IntegerTextBox" />
                <customControls:IntegerTextBox Grid.Row="3" Grid.Column="5"
                         MinWidth="200"
                         Value="{Binding IntValue, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnNotifyDataErrors=True}" />

实现目标的步骤

在

ResourceDictionary

 中，所有

TextBox

 控件的行为都会被修改，以便在发现验证错误时删除“红框”，并显示

ViewModel 中提供的验证错误。

<ResourceDictionary xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
    <Style TargetType="TextBox">
        <!-- Sets basic look of the TextBox -->
        <Setter Property="Padding" Value="2 1" />
        <Setter Property="BorderBrush" Value="LightGray" />
        <Setter Property="BorderThickness" Value="1" />

        <!-- Removes the red border around the TextBox, if validation found errors -->
        <Setter Property="Validation.ErrorTemplate">
            <Setter.Value>
                <ControlTemplate>
                    <AdornedElementPlaceholder />
                </ControlTemplate>
            </Setter.Value>
        </Setter>      
        
        <!-- Enables the UI to show the error messages -->
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate>
                    <StackPanel>
                        <Border Padding="{TemplateBinding Padding}" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" CornerRadius="3">
                            <ScrollViewer x:Name="PART_ContentHost" />
                        </Border>
                        <ItemsControl ItemsSource="{TemplateBinding Validation.Errors}" Margin="0 5 0 5">
                            <ItemsControl.ItemTemplate>
                                <DataTemplate>
                                    <TextBlock Foreground="Red" FontStyle="Italic" Text="{Binding ErrorContent}" />
                                </DataTemplate>
                            </ItemsControl.ItemTemplate>
                        </ItemsControl>
                    </StackPanel>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>
</ResourceDictionary>

此外，还添加了一些事件来在将数据输入到

TextBox

 控件时验证输入。那里的线程显示了我最喜欢的两个解决方案。一种是使用

Regex

，另一种是使用

int.TryParse()

。为了捕获像

space

、

backspace

和

delete

 这样的输入，事件处理程序正在处理这些输入。

    [GeneratedRegex("[^0-9]+")]
    private static partial Regex IntegerPositiveValuesOnlyRegex();

    // one option
    private void TextBox_PreviewTextInput(object sender, TextCompositionEventArgs e)
    {
        e.Handled = IntegerPositiveValuesOnlyRegex().IsMatch(e.Text);
    }

    // another option
    private void TextBox_PreviewTextInput(object sender, TextCompositionEventArgs e)
    {
        e.Handled = !int.TryParse((sender as TextBox)!.Text,
            NumberStyles.Integer,
            CultureInfo.InvariantCulture,
            out int validInteger);
    }

存在的问题

验证错误的可视化

TextBox

正在按预期工作（没有红色框；控件下方有红色错误消息）

Custom TextBox

 正在按预期工作（没有红色框；控件下方有红色错误消息）

Custom IntegerTextBox
```
显示红色框且不显示错误消息
```

捕捉输入

TextBox

抛出很多异常并接受所有键和值（但是，这是预期的结果）

Custom TextBox

 只允许整数；没有逗号，没有小数点，没有

-

；但按

space

、

backspace

或

delete

 会引发异常

Custom IntegerTextBox

按预期工作（完全没有例外；仅接受正整数值）

这就是我需要你帮助的地方！

我遗漏了一些东西，为什么

TextBox

控件的行为不同。至少

Custom IntegerTextBox

我想按预期工作。

完整代码

HomeView.xaml

<UserControl x:Class="SampleTextBoxValidation.Views.Screens.HomeView"
             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" 
             xmlns:local="clr-namespace:SampleTextBoxValidation.Views.Screens" 
             xmlns:viewModels="clr-namespace:SampleTextBoxValidation.ViewModels" 
             xmlns:customControls="clr-namespace:SampleTextBoxValidation.Views.CustomControls"
             mc:Ignorable="d" 
             d:DataContext="{d:DesignInstance Type=viewModels:HomeViewModel}"
             d:DesignHeight="600" d:DesignWidth="800">

    <Border CornerRadius="10" BorderThickness="1" BorderBrush="Black" Background="MintCream" Padding="5">
        <DockPanel>
            <!-- *** The UI's title *** -->
            <Label DockPanel.Dock="Top" HorizontalAlignment="Center"
               Content="Home Screen" 
               Margin="0 0 0 20"
               FontSize="14" FontWeight="Bold">
            </Label>

            <!-- *** The UI's footer *** -->
            <Label DockPanel.Dock="Bottom" HorizontalAlignment="Center"
               Content="Testing CommunityToolkit.Mvvm => ObservableValidator on several user controls." 
               Margin="0 20 0 0"
               FontSize="10" FontWeight="Bold">
            </Label>

            <!-- Button components -->
            <StackPanel DockPanel.Dock="Bottom" Orientation="Horizontal" HorizontalAlignment="Center">
                <Button  
                        Margin="15 20 15 5"
                        Command="{Binding DiscardButtonCommand}"
                        Content="Discard" />
                <Button 
                        Margin="15 20 15 5"
                        Command="{Binding LoadDataButtonCommand}"
                        Content="Load Data" />
                <Button 
                        Margin="15 20 15 5"
                        Command="{Binding SaveDataButtonCommand}"
                        Content="Save Data" />
            </StackPanel>

            <!-- *** The UI's body *** -->
            <Grid DockPanel.Dock="Top" HorizontalAlignment="Center">
                <Grid.ColumnDefinitions>
                    <ColumnDefinition Width="*" />
                    <ColumnDefinition Width="Auto" />
                    <ColumnDefinition Width="Auto" />
                    <ColumnDefinition Width="Auto" />
                    <ColumnDefinition Width="Auto" />
                    <ColumnDefinition Width="Auto" />
                    <ColumnDefinition Width="*" />
                </Grid.ColumnDefinitions>
                <Grid.RowDefinitions>
                    <RowDefinition Height="Auto"/>
                    <RowDefinition Height="Auto"/>
                    <RowDefinition Height="Auto"/>
                    <RowDefinition Height="Auto"/>
                    <RowDefinition Height="Auto"/>
                    <RowDefinition Height="Auto"/>
                    <RowDefinition Height="Auto"/>
                    <RowDefinition Height="Auto"/>
                    <RowDefinition Height="Auto"/>
                    <RowDefinition Height="*"/>
                </Grid.RowDefinitions>

                <!-- A column to seperate the user components on the left and right -->
                <Rectangle Grid.Column="2" Grid.Row="0" Grid.RowSpan="10" MinWidth=" 20" />
                <Rectangle Grid.Column="4" Grid.Row="0" Grid.RowSpan="10" MinWidth=" 20" />

                <!-- FirstName components -->
                <Label Grid.Row="0" Grid.Column="1" Content="First Name" />
                <TextBox Grid.Row="1" Grid.Column="1"
                         MinWidth="200"
                         Text="{Binding FirstName, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnNotifyDataErrors=True}" />
                <!-- LastName components -->
                <Label Grid.Row="0" Grid.Column="3" Content="Last Name" />
                <TextBox Grid.Row="1" Grid.Column="3"
                         MinWidth="200"
                         Text="{Binding LastName, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnNotifyDataErrors=True}" />

                <!-- Integer components -->
                <Label Grid.Row="2" Grid.Column="1" Content="Integer TextBox" />
                <TextBox Grid.Row="3" Grid.Column="1"
                         MinWidth="200"
                         Text="{Binding IntValue, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnNotifyDataErrors=True}" />
                <Label Grid.Row="2" Grid.Column="3" Content="Custom TextBox" />
                <TextBox x:Name="CustomTextBox" 
                         Grid.Row="3" Grid.Column="3"
                         HorizontalContentAlignment="Right"
                         MinWidth="200"
                         Text="{Binding IntValue, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnNotifyDataErrors=True}" />
                <Label Grid.Row="2" Grid.Column="5" Content="Custom IntegerTextBox" />
                <customControls:IntegerTextBox Grid.Row="3" Grid.Column="5"
                         MinWidth="200"
                         Value="{Binding IntValue, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnNotifyDataErrors=True}" />

                <!-- Decimal components -->
                <Label Grid.Row="4" Grid.Column="1" Content="Decimal StringFormat {0:C}" />
                <TextBox Grid.Row="5" Grid.Column="1"
                         MinWidth="200"
                         Text="{Binding DecimalValue, StringFormat={}{0:C}, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnNotifyDataErrors=True}" />
                <Label Grid.Row="4" Grid.Column="3" Content="Decimal As String" />
                <TextBox Grid.Row="5" Grid.Column="3"
                         MinWidth="200"
                         Text="{Binding DecimalValueAsString, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnNotifyDataErrors=True}" />

                <!-- Double components -->
                <Label Grid.Row="6" Grid.Column="1" Content="Double StringFormat {0:F2}" />
                <TextBox Grid.Row="7" Grid.Column="1"
                         MinWidth="200"
                         Text="{Binding DoubleValue, StringFormat={}{0:F2}, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnNotifyDataErrors=True}" />
                <Label Grid.Row="6" Grid.Column="3" Content="Double As String" />
                <TextBox Grid.Row="7" Grid.Column="3"
                         MinWidth="200"
                         Text="{Binding DoubleValueAsString, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnNotifyDataErrors=True}" />

            </Grid>
        </DockPanel>

    </Border>
</UserControl>

HomeView.xaml.cs

using System.Diagnostics;
using System.Globalization;
using System.Text.RegularExpressions;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;

namespace SampleTextBoxValidation.Views.Screens;

public partial class HomeView : UserControl
{
    [GeneratedRegex("[^0-9]+")]
    private static partial Regex IntegerPositiveValuesOnlyRegex();

    public HomeView()
    {
        InitializeComponent();

        CustomTextBox.GotFocus += TextBox_GotFocus;
        CustomTextBox.PreviewTextInput += TextBox_PreviewTextInput;
        CustomTextBox.PreviewKeyUp += TextBox_PreviewKeyDown;
        CustomTextBox.TextChanged += TextBox_TextChanged;
    }

    private void TextBox_GotFocus(object sender, RoutedEventArgs e)
    {
        Debug.WriteLine($"Entered {nameof(TextBox_GotFocus)}");

        (sender as TextBox)!.SelectAll();
    }

    private void TextBox_PreviewTextInput(object sender, TextCompositionEventArgs e)
    {
        Debug.WriteLine($"Entered {nameof(TextBox_PreviewTextInput)}");

        e.Handled = IntegerPositiveValuesOnlyRegex().IsMatch(e.Text);
    }

    private void TextBox_PreviewKeyDown(object sender, KeyEventArgs e)
    {
        Debug.WriteLine($"Entered {nameof(TextBox_PreviewKeyDown)}");

        if (e.Key == Key.Space)
        {
            e.Handled = true;
        }
        else if (e.Key == Key.Back)
        {
            if ((sender as TextBox)!.Text.Length == 1)
            {
                (sender as TextBox)!.SelectAll();
                e.Handled = true;
            }
        }
        else if (e.Key == Key.Delete)
        {
            if ((sender as TextBox)!.Text.Length == 1)
            {
                (sender as TextBox)!.SelectAll();
                e.Handled = true;
            }
        }
    }

    private void TextBox_TextChanged(object sender, TextChangedEventArgs e)
    {
        Debug.WriteLine($"Entered {nameof(TextBox_TextChanged)}");

        bool valid = int.TryParse((sender as TextBox)!.Text,
            NumberStyles.Integer,
            CultureInfo.InvariantCulture,
            out int validInteger);

        if (valid)
        {
            CustomTextBox.Text = validInteger.ToString();
        }
        else
        {
            CustomTextBox.Text = 999.ToString(); // For testing, only, to show there was a problem.
        }
    }

}

IntegerTextBox.xaml

<UserControl x:Class="SampleTextBoxValidation.Views.CustomControls.IntegerTextBox"
             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" 
             xmlns:local="clr-namespace:SampleTextBoxValidation.Views.CustomControls"
             mc:Ignorable="d" 
             d:DesignHeight="450" d:DesignWidth="800">

    <!-- Refer to the code behind file to see this user control's logic! -->
    <!-- Binding Value => this is a custom dependency property that is registered to this user control -->
    <!-- RelativeSource => this is needed to enable the databinding in both directions -->
    <TextBox x:Name="CustomIntegerTextBox"
             HorizontalContentAlignment="Right"
             Text="{Binding Value, 
                    Mode=TwoWay, 
                    UpdateSourceTrigger=PropertyChanged, 
                    ValidatesOnNotifyDataErrors=True,
                    RelativeSource={RelativeSource Mode=FindAncestor, AncestorType={x:Type UserControl}}}" />

</UserControl>

IntegerTextBox.xaml.cs

using System.Diagnostics;
using System.Globalization;
using System.Text.RegularExpressions;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;

namespace SampleTextBoxValidation.Views.CustomControls
{
    public partial class IntegerTextBox : UserControl
    {
        [GeneratedRegex("[^0-9]+")]
        private static partial Regex IntegerPositiveValuesOnlyRegex();

        public static readonly DependencyProperty DependencyPropertyOfValue =
            DependencyProperty.Register(nameof(Value), typeof(int), typeof(IntegerTextBox), new PropertyMetadata(0));

        public int Value
        {
            get { return (int)GetValue(DependencyPropertyOfValue); }
            set { SetValue(DependencyPropertyOfValue, value); }
        }

        public IntegerTextBox()
        {
            InitializeComponent();

            CustomIntegerTextBox.TextChanged += TextBox_TextChanged;
            CustomIntegerTextBox.GotFocus += TextBox_GotFocus;
            CustomIntegerTextBox.PreviewTextInput += TextBox_PreviewTextInput;
            CustomIntegerTextBox.PreviewKeyDown += TextBox_PreviewKeyDown;
        }

        private void TextBox_GotFocus(object sender, RoutedEventArgs e)
        {
            Debug.WriteLine($"Entered {nameof(TextBox_GotFocus)}");

            (sender as TextBox)!.SelectAll();
        }

        private void TextBox_PreviewTextInput(object sender, TextCompositionEventArgs e)
        {
            Debug.WriteLine($"Entered {nameof(TextBox_PreviewTextInput)}");

            e.Handled = IntegerPositiveValuesOnlyRegex().IsMatch(e.Text);
        }

        private void TextBox_PreviewKeyDown(object sender, KeyEventArgs e)
        {
            Debug.WriteLine($"Entered {nameof(TextBox_PreviewKeyDown)}");

            if (e.Key == Key.Space)
            {
                e.Handled = true;
            }
            else if (e.Key == Key.Back)
            {
                if ((sender as TextBox)!.Text.Length == 1)
                {
                    (sender as TextBox)!.SelectAll();
                    e.Handled = true;
                }
            }
            else if (e.Key == Key.Delete)
            {
                if ((sender as TextBox)!.Text.Length == 1)
                {
                    (sender as TextBox)!.SelectAll();
                    e.Handled = true;
                }
            }
        }

        private void TextBox_TextChanged(object sender, TextChangedEventArgs e)
        {
            Debug.WriteLine($"Entered {nameof(TextBox_TextChanged)}");

            bool valid = int.TryParse((sender as TextBox)!.Text,
                NumberStyles.Integer,
                CultureInfo.InvariantCulture,
                out int validInteger);

            if (valid)
            {
                Value = validInteger;
            }
            else
            {
                Value = 999; // for testing, only, to show an error was not handled
            }
        }
    }
}

>><<< Edit after implementing the changes provided by >

更新代码后，仍然有一个问题。

Custom TextBox 中输入值，则 Custom IntegerTextBox 正在正确验证输入；它显示错误消息，但没有红色框；但Custom IntegerTextBox中没有显示任何内容
Custom IntegerTextBox 中输入值，则验证正常工作并且其他两个控件显示内容

不知何故，属性

Value

需要更新和显示。这是如何实现的？

添加

PropertyChanged

 并没有改变行为。

    public int Value
    {
        get { return (int)GetValue(DependencyPropertyOfValue); }
        set 
        { 
            SetValue(DependencyPropertyOfValue, value);
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Value)));
        }
    }

代码现在看起来像这样。请注意，类名称暂时从

IntegerTextBox

 更改为

CustomTextBox

。

<customControls:CustomTextBox
            Grid.Row="3" Grid.Column="5"
            MinWidth="200"
            HorizontalContentAlignment="Right"
            Value="{Binding IntValue, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged, ValidatesOnNotifyDataErrors=True}" />
 />

using System.Diagnostics;
using System.Globalization;
using System.Text.RegularExpressions;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Input;

namespace SampleTextBoxValidation.Views.CustomControls;

public partial class CustomTextBox : TextBox
{
    [GeneratedRegex("[^0-9]+")]
    private static partial Regex IntegerPositiveValuesOnlyRegex();

    public static readonly DependencyProperty DependencyPropertyOfValue =
        DependencyProperty.Register(nameof(Value), typeof(int), typeof(CustomTextBox), new PropertyMetadata(0));

    public int Value
    {
        get { return (int)GetValue(DependencyPropertyOfValue); }
        set { SetValue(DependencyPropertyOfValue, value); }
    }

    public CustomTextBox()
    {
        TextChanged += TextBox_TextChanged;
        GotFocus += TextBox_GotFocus;
        PreviewTextInput += TextBox_PreviewTextInput;
        PreviewKeyDown += TextBox_PreviewKeyDown;
    }

    private void TextBox_GotFocus(object sender, RoutedEventArgs e)
    {
        Debug.WriteLine($"Entered {nameof(TextBox_GotFocus)}");

        (sender as TextBox)!.SelectAll();
    }

    private void TextBox_PreviewTextInput(object sender, TextCompositionEventArgs e)
    {
        Debug.WriteLine($"Entered {nameof(TextBox_PreviewTextInput)}");

        e.Handled = IntegerPositiveValuesOnlyRegex().IsMatch(e.Text);
    }

    private void TextBox_PreviewKeyDown(object sender, KeyEventArgs e)
    {
        Debug.WriteLine($"Entered {nameof(TextBox_PreviewKeyDown)}");

        if (e.Key == Key.Space)
        {
            e.Handled = true;
        }
        else if (e.Key == Key.Back)
        {
            if ((sender as TextBox)!.Text.Length == 1)
            {
                (sender as TextBox)!.SelectAll();
                e.Handled = true;
            }
        }
        else if (e.Key == Key.Delete)
        {
            if ((sender as TextBox)!.Text.Length == 1)
            {
                (sender as TextBox)!.SelectAll();
                e.Handled = true;
            }
        }
    }

    private void TextBox_TextChanged(object sender, TextChangedEventArgs e)
    {
        Debug.WriteLine($"Entered {nameof(TextBox_TextChanged)}");

        bool valid = int.TryParse((sender as TextBox)!.Text,
            NumberStyles.Integer,
            CultureInfo.InvariantCulture,
            out int validInteger);

        if (valid)
        {
            Value = validInteger;
        }
        else
        {
            Value = 999; // for testing, only, to show an error was not handled
        }
    }
}

Answer 1

自定义 IntegerTextBox 显示红色框且不显示错误消息

不同之处在于，

IntegerTextBox

是一个简单包装普通

UserControl

的

TextBox

。这不是定制的

TextBox

。您的自定义

Validation.ErrorTemplate

 将不适用于该控件。

您应该将

IntegerTextBox

 类修改为扩展

TextBox

 的自定义控件。删除 XAML 文件并创建一个独立的类：

public partial class IntegerTextBox : TextBox
{
    [GeneratedRegex("[^0-9]+")]
    private static partial Regex IntegerPositiveValuesOnlyRegex();

    public static readonly DependencyProperty DependencyPropertyOfValue =
        DependencyProperty.Register(nameof(Value), typeof(int), typeof(IntegerTextBox), new PropertyMetadata(0));

    public int Value
    {
        get { return (int)GetValue(DependencyPropertyOfValue); }
        set { SetValue(DependencyPropertyOfValue, value); }
    }

    public IntegerTextBox()
    {
        TextChanged += TextBox_TextChanged;
        GotFocus += TextBox_GotFocus;
        PreviewTextInput += TextBox_PreviewTextInput;
        PreviewKeyDown += TextBox_PreviewKeyDown;
    }

    private void TextBox_GotFocus(object sender, RoutedEventArgs e)
    {
        Debug.WriteLine($"Entered {nameof(TextBox_GotFocus)}");

        (sender as TextBox)!.SelectAll();
    }

    private void TextBox_PreviewTextInput(object sender, TextCompositionEventArgs e)
    {
        Debug.WriteLine($"Entered {nameof(TextBox_PreviewTextInput)}");

        e.Handled = IntegerPositiveValuesOnlyRegex().IsMatch(e.Text);
    }

    private void TextBox_PreviewKeyDown(object sender, KeyEventArgs e)
    {
        Debug.WriteLine($"Entered {nameof(TextBox_PreviewKeyDown)}");

        if (e.Key == Key.Space)
        {
            e.Handled = true;
        }
        else if (e.Key == Key.Back)
        {
            if ((sender as TextBox)!.Text.Length == 1)
            {
                (sender as TextBox)!.SelectAll();
                e.Handled = true;
            }
        }
        else if (e.Key == Key.Delete)
        {
            if ((sender as TextBox)!.Text.Length == 1)
            {
                (sender as TextBox)!.SelectAll();
                e.Handled = true;
            }
        }
    }

    private void TextBox_TextChanged(object sender, TextChangedEventArgs e)
    {
        Debug.WriteLine($"Entered {nameof(TextBox_TextChanged)}");

        bool valid = int.TryParse((sender as TextBox)!.Text,
            NumberStyles.Integer,
            CultureInfo.InvariantCulture,
            out int validInteger);

        if (valid)
        {
            Value = validInteger;
        }
        else
        {
            Value = 999; // for testing, only, to show an error was not handled
        }
    }
}

然后，根据

Style

 中的

TextBox

 样式为自定义控件定义

TextBoxStyle.xaml

：

<Style TargetType="customControls:IntegerTextBox" BasedOn="{StaticResource {x:Type TextBox}}" />

如何将NotifyDataErrorInfo传递到自定义TextBox用户控件？

问题描述投票：0回答：1

目标

设定

>><<< Edit after implementing the changes provided by >

1个回答

最新问题

如何将NotifyDataErrorInfo传递到自定义TextBox用户控件？

问题描述 投票：0回答：1

目标

设定

>><<< Edit after implementing the changes provided by >

1个回答

最新问题

问题描述投票：0回答：1