首页 > 解决方案 > WPF 绑定:禁用 TextBoxes + 验证和 DataContext 问题

问题描述

我的简单程序有两个窗口:

所述文本框的特征还在于验证绑定。现在我的验证任务完美无缺,但我无法使绑定到IsEnabledTextBox 属性工作。

这是我的 XAML 的片段,其中包含一个 TextBox(目前是我绑定的唯一一个):

<TextBox x:Name="tbSlave1" Validation.Error="ValidationError" IsEnabled="{Binding TextBoxEnabled}" Text="{Binding UpdateSourceTrigger=PropertyChanged, Path=SlavePoint1Name, ValidatesOnDataErrors=true, NotifyOnValidationError=true}"/>

虽然这是我的第二个窗口类:

public partial class GeneratorWindow : Window, INotifyPropertyChanged
{
    private readonly Validator validator = new Validator();

    private int noOfErrorsOnScreen;

    public GeneratorWindow()
    {
        this.InitializeComponent();
        this.grid.DataContext = this.validator;
    }

    public int NumberOfPoints { private get; set; }

    public int MainPDC { private get; set; }

    public event PropertyChangedEventHandler PropertyChanged;

    private void NotifyPropertyChanged(String info)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(info));
        }
    }

    private Boolean IsEnabled;
    public Boolean TextBoxEnabled
    {
        get { return IsEnabled; }

        set
        {
            IsEnabled = value;
            NotifyPropertyChanged("TextBoxEnabled");
        }
    }

    private void ValidationError(object sender, ValidationErrorEventArgs eventArgs)
    {
        if (eventArgs.Action == ValidationErrorEventAction.Added)
        {
            this.noOfErrorsOnScreen++;
        }
        else
        {
            this.noOfErrorsOnScreen--;
        }
    }

    private void ValidationCanBeExecuted(object sender, CanExecuteRoutedEventArgs eventArgs)
    {
        eventArgs.CanExecute = this.noOfErrorsOnScreen == 0;
        eventArgs.Handled = true;
    }

    private void ValidationExecuted(object sender, ExecutedRoutedEventArgs eventArgs)
    {
        // If the validation was successful, let's generate the files.
        this.Close();

        eventArgs.Handled = true;
    }
}

现在,我得到的是我的窗口被禁用(无法选择任何文本框),显然,这是:

System.Windows.Data 错误:40:BindingExpression 路径错误:在“对象”“验证器”(HashCode = 14499481)上找不到“TextBoxEnabled”属性。BindingExpression:Path=TextBoxEnabled; DataItem='验证器' (HashCode=14499481); 目标元素是'TextBox'(名称='tbSlave1');目标属性是“IsEnabled”(类型“布尔”)

据我所知,罪魁祸首是我DataContext在类构造函数中管理的方式。我可能需要在验证器行中添加一些东西或完全改变它,但我不明白怎么做。

标签: c#wpfbinding

解决方案


我认为如果您将 设置DataContextGeneratorWindow并相应地更新您的绑定,您应该没问题。为此,您需要更改Validator为公共财产。

更改验证器定义:

public Validator Validator { get; } = new Validator();

数据上下文:

this.grid.DataContext = this;

更新绑定:

<TextBox x:Name="tbSlave1" 
         Validation.Error="ValidationError" 
         IsEnabled="{Binding TextBoxEnabled}" 
         Text="{Binding UpdateSourceTrigger=PropertyChanged, 
                        Path=Validator.SlavePoint1Name, 
                        ValidatesOnDataErrors=true, 
                        NotifyOnValidationError=true}"/>

推荐阅读