如何在启用文本框时触发新的验证

本文关键字：验证 启用 文本 | 更新日期: 2023-09-27 18:27:36

在wpf对话框窗口中，我有一个复选框，用于启用和禁用文本框。该文本框已将ValidatesDataErrors设置为True。通过IDataErrorInfo，如果复选框被选中，我只检查该文本框的值。

我的问题是，如果用户选中复选框，就不会对文本框执行新的验证，因此我不会得到指示错误的红色框。

为了演示，这里有一个小样本：

<Window x:Class="Validation.ValidationWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="ValidationWindow" Height="300" Width="300">
<DockPanel LastChildFill="False">
    <CheckBox DockPanel.Dock="Top" IsChecked="{Binding InputAllowed}">Input allowed</CheckBox>
    <StackPanel DockPanel.Dock="Top" Orientation="Horizontal">
        <Label>InputValue</Label>
        <TextBox Text="{Binding InputValue, ValidatesOnDataErrors=True}" IsEnabled="{Binding InputAllowed}" Width="50"/>
    </StackPanel>
    <StackPanel DockPanel.Dock="Top" Orientation="Horizontal">
        <Label>InputValue2</Label>
        <TextBox Text="{Binding InputValue2, ValidatesOnDataErrors=True}" Width="50"/>
    </StackPanel>
    <Button DockPanel.Dock="Bottom" Click="OnOk">Ok</Button>
</DockPanel>
</Window>

代码背后：

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
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.Shapes;
namespace Validation
{
/// <summary>
/// Interaction logic for ValidationWindow.xaml
/// </summary>
public partial class ValidationWindow : Window, IDataErrorInfo
{
    public bool InputAllowed
    {
        get { return (bool)GetValue(InputAllowedProperty); }
        set { SetValue(InputAllowedProperty, value); }
    }
    public static readonly DependencyProperty InputAllowedProperty =
        DependencyProperty.Register("InputAllowed", typeof(bool), typeof(ValidationWindow), new PropertyMetadata(false));
    public int InputValue
    {
        get { return (int)GetValue(InputValueProperty); }
        set { SetValue(InputValueProperty, value); }
    }
    public static readonly DependencyProperty InputValueProperty =
        DependencyProperty.Register("InputValue", typeof(int), typeof(ValidationWindow), new PropertyMetadata(0));
    public int InputValue2
    {
        get { return (int)GetValue(InputValue2Property); }
        set { SetValue(InputValue2Property, value); }
    }
    public static readonly DependencyProperty InputValue2Property =
        DependencyProperty.Register("InputValue2", typeof(int), typeof(ValidationWindow), new PropertyMetadata(0));

    public ValidationWindow()
    {
        InitializeComponent();
        DataContext = this;
    }
    private void OnOk(object sender, RoutedEventArgs e)
    {
        string msg = Error;
        if(!string.IsNullOrEmpty(Error))
        {
            MessageBox.Show(Error);
            return;
        }
        DialogResult = true;
    }
    #region IDataErrorInfo Members
    public string Error
    {
        get { return ((IDataErrorInfo)this)[null]; }
    }
    public string this[string columnName]
    {
        get
        {
            string msg = string.Empty;
            if(string.IsNullOrEmpty(columnName))
            {
                msg += ((IDataErrorInfo)this)["InputValue"];
                msg += ((IDataErrorInfo)this)["InputValue2"];
            }
            else
            {
                switch(columnName)
                {
                case "InputValue":
                    if(InputAllowed)
                    {
                        if(InputValue <= 0)
                        {
                            msg += "InputValue must be greater that 0!";
                        }
                    }
                    break;
                case "InputValue2":
                    if(InputValue2 <= 0)
                    {
                        msg += "InputValue2 must be greater that 0!";
                    }
                    break;
                }
            }
            return msg;
        }
    }
    #endregion
}
}

如何在启用文本框时触发新的验证

我们一直在使用它来强制验证程序正式更改文本后，如果您响应复选框的事件调用它，应该也能正常工作：

var binding = someTextBox.GetBindingExpression( TextBox.TextProperty );
if( binding == null )
  return;
binding.UpdateSource();

与stijn的解决方案没有实际区别，但由于我们都有点懒惰：

public static class DependencyPropertyExtensions
{
    public static bool UpdateSource(this FrameworkElement source, DependencyProperty property)
    {
        var binding = source.GetBindingExpression(property);
        if (binding != null)
        {
            binding.UpdateSource();
            return true;
        }
        return false;
    }
}
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