从代码隐藏到XAML的简单数据绑定

Question

我是WPF概念的新手.我想在文本框中显示一个字符串.我尝试了以下C#代码和XAML将字符串绑定到TextBox.Text属性.C#代码:

public partial class Window1 : Window
{
    public int TmpVal;
    public string TmpStr;

     public Window1()
    {
        TmpVal = 50;
        TmpStr = "Windows Created";
        InitializeComponent();
        this.DataContext = this;
    }
    private void viewButton_Click(object sender, RoutedEventArgs args)
    {
        TmpStr = "Button clicked";
    }
}

}

XAML:

 <Window x:Class="TestWPF.Window1"
   xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
   xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
Title="Window1" Height="600" Width="800" x:Name="ThisWindow">
<Grid>
    <TextBox Name="txtTest1" Margin="200,0,200,200" HorizontalAlignment="Left" Height="50" Width="200" Text="{Binding TmpStr, ElementName=ThisWindow}" />
    <Button Name="butTest1"  Click="viewButton_Click">Test123</Button>
</Grid>
</Window>

执行时,我的文本框中总是会出现空白文本(即使我调用了click事件).
我浏览了stackoverflow网站,但无法解决问题(虽然很多问题都接近这个问题)
有人建议我,如果有什么被忽视或错过了吗？

Answer 1

数据绑定不适用于字段.使用属性代替:

public int TmpVal {get; set;}
public string TmpStr {get; set;}

此外,如果您希望文本框自动从数据中获取更改,您理想情况下需要实现INotifyPropertyChanged或使其成为依赖项属性,或者为每个XXX属性设置XXXChanged事件(这不再起作用).

<Window x:Class="WpfApplication5.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" x:Name="ThisWindow">
    <StackPanel>
        <TextBox Name="txtTest1" Text="{Binding TmpStr, ElementName=ThisWindow}" />
        <Button Name="butTest1"  Click="viewButton_Click">Test123</Button>
    </StackPanel>
</Window>

而背后的代码:

public partial class Window1 : Window, INotifyPropertyChanged
{
    public Window1()
    {
        this.TmpStr = "Windows Created";
        this.InitializeComponent();
        this.DataContext = this;
    }

    public event PropertyChangedEventHandler PropertyChanged;

    public string TmpStr { get; set; }

    public int TmpVal { get; set; }

    private void viewButton_Click(object sender, RoutedEventArgs args)
    {
        this.TmpStr = "Button clicked";
        if (this.PropertyChanged != null)
        {
            this.PropertyChanged(this, new PropertyChangedEventArgs("TmpStr"));
        }
    }
}