WPF C# 数据绑定 - MessageBox.Show

Question

让我首先声明我已经阅读了很多我头疼的线程，我已经尝试了其中的大部分但仍然没有成功。

我的问题很简单。我有一些状态要更新控件，我有一个绑定到对象 class 的文本框。

当我逐步执行代码时，textbox.Text 正在更新，但从未呈现。我注意到的是，如果我使用我熟悉的其他以 windows 为中心的东西，例如 MessageBox.Show();在我的循环内部，它中断了 MainWindow 并更新了文本框..！

MessageBox.Show() 中究竟是什么 allows/forces/coerces 渲染发生了，我不能直接调用它吗？我处理这个问题的方式似乎是最简单的版本，当你需要数据绑定才能开箱即用而没有任何繁琐的工作时..希望我错过了简单的按钮..

任何帮助都将非常有价值。提前感谢您的宝贵时间。

public partial class MainWindow : Window{

private ExampleDataClass objClass = null;

public MainWindow()
{
    InitializeComponent();
    objClass = new ExampleDataClass();
    this.DataContext = objClass;
}

public int j = 0;

private string _someLocalString = "";

public string SomeLocalString
{
    get { return _someLocalString; }
    set { _someLocalString = value; }
}

public string strstr = ""; 


private void textBox_TextChanged(object sender, TextChangedEventArgs e)
{
    //MessageBox.Show(""); // this will make it work.. 
}

private void button_Click(object sender, RoutedEventArgs e)
{

    SomeLongRunningCode(out strstr);
}

public void SomeLongRunningCode(out string SomeProperty)
{
    for (int i = 1; i <= 600; i++)
    {
        SomeLocalString = i.ToString();
        objClass.X = _someLocalString;

        //   BindingOperations.GetBindingExpressionBase(textBox, TextBox.TextProperty).UpdateTarget();
        //    textBox.Dispatcher.BeginInvoke(System.Windows.Threading.DispatcherPriority.Normal,
        //       new Action(delegate() { textBox.Text = i.ToString();}));
    }



    SomeProperty = "Exited SomeLongRunningCode";
}}}

<Window x:Class="DataBinding.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
    xmlns:local="clr-namespace:DataBinding"
    mc:Ignorable="d"
    Title="MainWindow" Height="109.157" Width="176.303">
<Grid x:Name="myGrid">
    <TextBox x:Name="textBox" Text="{Binding X,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}" Focusable = "true" HorizontalAlignment="Left" Height="23" Margin="22,14,0,0" TextWrapping="Wrap"  VerticalAlignment="Top" Width="120" TextChanged="textBox_TextChanged" />
    <Button x:Name="button" Content="Button" HorizontalAlignment="Left" Margin="24,46,0,0" VerticalAlignment="Top" Width="75" Click="button_Click"/>

</Grid>

public class ExampleDataClass : INotifyPropertyChanged
{

    private string _x = "";
    public string X
    {
        get { return _x;}
        set
        {
            if (_x != null)
            {
                _x = value;
                OnPropertyChanged("X");
            }
        }
    }

    public event PropertyChangedEventHandler PropertyChanged;
    public void OnPropertyChanged(string info)
    {
        var handler = this.PropertyChanged;
        if (handler != null)
        {
            handler(this, new PropertyChangedEventArgs(info));
        }
    }

}}

Answer 1

textBox 未更新，因为线程在 for 循环期间被阻塞。

如果您运行 SomeLongRunningCode 异步，您将看到您的代码按预期工作。

private void button_Click(object sender, RoutedEventArgs e)
{

    Task.Run(() => SomeLongRunningCode(out strstr));
}

public void SomeLongRunningCode(out string SomeProperty)
{
    for (int i = 1; i <= 600; i++)
    {
        SomeLocalString = i.ToString();
        objClass.X = _someLocalString;
        Thread.Sleep(100);   // Slowing down so we can see the text change
    }



        SomeProperty = "Exited SomeLongRunningCode";
}

WPF C# 数据绑定 - MessageBox.Show

WPF C# Databinding - MessageBox.Show

c#

wpf

data-binding

messagebox