当我的 wpf 绑定验证失败并且包含面板不再可见时，如何摆脱红色矩形?

问题描述

我遇到了使用 ExceptionValidationRule 使用 wpf 数据绑定和验证的情况.

I have a situation where I am using wpf data binding and validation using the ExceptionValidationRule.

解决方案的另一部分涉及折叠一些面板并显示其他面板.

Another part of the solution invovles collapsing some panels and showing others.

如果设置了验证异常 - 即 UI 在存在验证问题的 UI 元素周围显示红色边框，并且包含面板已折叠，但仍会显示红色边框.这显然不是故意的?有解决方法吗?有谁知道这是设计使然吗?

If a validation exception is set - i.e. the UI is showing a red border around the UI element with the validation problem, and the containing panel is collapsed, the red border is still displayed. This is clearly not meant to be? Is there a workaround for this? Anyone know if this is by design?

提供了最少的代码示例(不是我的实际代码，而是复制了问题).创建一个新的 WpfApplication(我称之为 WpfDataBindingProblem).

Minimal code example provided (not my actual code, but replicates the problem). Create a new WpfApplication (I called mine WpfDataBindingProblem).

window1的xaml如下:

The xaml for window1 is as follows:

<Window x:Class="WpfDataBindingProblem.Window1"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="Window1" Height="300" Width="300">
    <StackPanel Margin="5">

        <StackPanel Name="panel1" Visibility="Visible" Margin="5">
            <TextBox Name="DataBoundTextBox">
                <Binding Path="TextValue">
                    <Binding.ValidationRules>
                        <ExceptionValidationRule/>
                    </Binding.ValidationRules>
                </Binding>
            </TextBox>
        </StackPanel>

        <StackPanel Name="panel2" Visibility="Collapsed" Margin="5">
            <TextBlock>
                The quick brown fox jumps over the lazy dog.
            </TextBlock>
        </StackPanel>

        <Button Click="Button_Click" Margin="5">
            Toggle panels
        </Button>

    </StackPanel>
</Window>

window1的代码如下:

The code for window1 is as follows:

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Data;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Windows.Navigation;
using System.Windows.Shapes;

namespace WpfDataBindingProblem {

    public partial class Window1 : Window {
        public Window1() {
            InitializeComponent();

            this.DataContext = new MyClass("default");
        }

        private void Button_Click(object sender, RoutedEventArgs e) {
            panel1.Visibility = panel1.Visibility == Visibility.Collapsed ?
                Visibility.Visible : Visibility.Collapsed;
            panel2.Visibility = panel2.Visibility == Visibility.Collapsed ?
                Visibility.Visible : Visibility.Collapsed;
        }
    }

    public class MyClass : INotifyPropertyChanged {

        private string mTextValue;

        public MyClass(string defaultText) {
            TextValue = defaultText;
        }

        public string TextValue {
            get {
                return mTextValue;
            }
            set {
                mTextValue = value;
                if (string.IsNullOrEmpty(mTextValue)) {
                    throw new ApplicationException("Text value cannot be empty");
                }
                OnPropertyChanged(new PropertyChangedEventArgs("TextValue"));
            }
        }

        public event PropertyChangedEventHandler PropertyChanged;

        protected virtual void OnPropertyChanged(PropertyChangedEventArgs e) {
            if (this.PropertyChanged != null) {
                this.PropertyChanged(this, e);
            }
        }
    }

}

要重现该问题，请运行该应用程序.从文本框中删除 default 文本并关闭标签 - 显示红色矩形表示验证问题.单击按钮.包含红色矩形控件的面板被隐藏并显示另一个面板，但红色矩形仍然存在.啊！

To reproduce the problem, run the application. Delete the default text from the textbox and tab off - red rectangle is shown indicating a validation problem. Click the button. Panel containing control with red rectangle is hidden and another panel is shown, but the red rectangle remains. Aargh!

非常感谢所有帮助.

PS 为长问题道歉！

推荐答案

如果我没记错的话，这是一个已知问题.我们重新设计了文本框以包含以下内容:

If I remember correctly, this is a known issue. We re-templated textbox to include the following:

<Setter Property="Validation.ErrorTemplate">
    <Setter.Value>
        <ControlTemplate>
            <ControlTemplate.Resources>
                <BooleanToVisibilityConverter x:Key="converter" />
        </ControlTemplate.Resources>
            <DockPanel LastChildFill="True">
                <Border 
                    BorderThickness="1"
                    BorderBrush="Red"
                    Visibility="{Binding ElementName=placeholder, Mode=OneWay, Path=AdornedElement.IsVisible, Converter={StaticResource converter}}">
                    <AdornedElementPlaceholder x:Name="placeholder" />
                </Border>
             </DockPanel>
         </ControlTemplate>
    </Setter.Value>
</Setter>

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