设置值时 WPF 文本框绑定未更新

Question

我有一个小程序来测试文本框数据绑定，当我更改文本框本身的值时它可以工作，但是当我尝试从代码隐藏中更改值时，变量已更新但文本框未更新.我环顾四周，但未能找到解决方案，因为我所看到的大多数是用于更新变量的文本框，这与我需要的相反。代码如下：

XAML：

<Grid>
    <TextBox Text="{Binding FirstName, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" HorizontalAlignment="Left" Height="23" Margin="127,37,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="120"/>
    <TextBox Text="{Binding LastName, Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" HorizontalAlignment="Left" Height="23" Margin="127,88,0,0" TextWrapping="Wrap" VerticalAlignment="Top" Width="120"/>
    <TextBlock HorizontalAlignment="Left" Margin="28,40,0,0" TextWrapping="Wrap" Text="First Name" VerticalAlignment="Top"/>
    <TextBlock HorizontalAlignment="Left" Margin="28,91,0,0" TextWrapping="Wrap" Text="Last Name" VerticalAlignment="Top"/>
    <Button x:Name="Name" Content="Name!" HorizontalAlignment="Left" Margin="145,212,0,0" VerticalAlignment="Top" Width="75" Click="Name_Click"/>

</Grid>

还有我的代码：

namespace WpfApplication1
{
public class UIControls : INotifyPropertyChanged
{
    public event PropertyChangedEventHandler PropertyChanged;
    private string _firstName;
    private string _lastName;

    protected void Notify(string propertyName)
    {
        if(this.PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
    }

    public string FirstName
    {
        get { return _firstName; }
        set
        {
            if (value != _firstName)
            {
                _firstName = value;
                Notify("FirstName");
            }

        }
    }
    public string LastName
    {
        get { return _lastName; }
        set
        {
            if (value != _lastName)
            {
                _lastName = value;
                Notify("LastName");
            }
        }
    }
}

public partial class MainWindow : Window
{
    public MainWindow()
    {
        InitializeComponent();
        UIControls viewModel = new UIControls();
        this.DataContext = viewModel;
    }

    private void Name_Click(object sender, RoutedEventArgs e)
    {
        UIControls ui = new UIControls();
        ui.FirstName = "Mike";
        ui.LastName = "Smith";
    }
}

}

Answer 1

你在每次按钮点击时都创建了新的 UIControls。新的 UIControls 未绑定到文本框。尝试创建绑定到 MainWindow 的私有文件，如下所示：

public partial class MainWindow : Window
{

    private UIControls viewModel;
    public MainWindow()
    {
        InitializeComponent();
        viewModel = new UIControls();
        this.DataContext = viewModel;
    }

    private void Name_Click(object sender, RoutedEventArgs e)
    {
        viewModel.FirstName = "Mike";
        viewModel.LastName = "Smith";
    }