无法向可观察集合列表框添加新行

Question

在我的项目中，我有以下页面：

Mainwindow.xaml

窗口1.xaml

用户.cs

App.xaml

我在User.cs申报了Name和Age财产，MainWindow.xaml我为ListBox做了一个ObservableCollection。 MainWindow有一个Button Add.当我们点击时 Add button .然后显示Window1.xaml窗体。它有两个姓名和年龄TextBoxes和一个按钮（ADD Name）。现在，我希望当我们单击Add Name button时，两个文本框中的详细信息都将附加到Mainwindow.xaml.cs上定义的ObservableCollection。

请建议我想要我可以做：

public partial class Window1 : Window
{
    
    public Window1()
    {
        InitializeComponent();
    }
    private void OnInit(object sender, RoutedEventArgs e)
    {
        string textA=textBox1.Text;
        int textB=Convert.ToInt32(textBox2.Text);
        this.DataContext = new User(textA, textB);
    }
    private void button1_Click(object sender, RoutedEventArgs e)
    {
        User user = (User)(this.DataContext);
        new MainWindow().observableCollection.Add(user);
        this.Close();
    }
}

现在我运行了这段代码，我无法获取用户对象中的值。

Answer 1

问题是您没有访问MainWindow CbservableCollection，而是正在创建一个新的MainWindow。

如果此Window1是一个对话框，您有几个选项

1. 将主窗口作为其所有者传递到 Window1 中
2. 使用 Window1 作为对话框，并在关闭时获取更改

我个人认为第二种选择是最好的，但这取决于你如何称呼Window1

示例 2：

主窗口类

public partial class MainWindow : Window
{
    private ObservableCollection<User> _myList = new ObservableCollection<User>();
    public MainWindow()
    {
        InitializeComponent();
    }
    public ObservableCollection<User> MyCollection
    {
        get { return _myList; }
        set { _myList = value; }
    }
    private void button1_Click_1(object sender, RoutedEventArgs e)
    {
        var dialog = new Window1();
        if (dialog.ShowDialog() == true)
        {
            MyCollection.Add(dialog.NewUser);
        }
    }
}

主窗口 xaml

<Window x:Class="WpfApplication8.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="233" Width="405" Name="UI">
    <Grid DataContext="{Binding ElementName=UI}" >
        <ListBox ItemsSource="{Binding MyCollection}" DisplayMemberPath="TextA"  Margin="0,0,0,47" />
        <Button Content="Add" Height="23" HorizontalAlignment="Left" Margin="0,0,0,12" Name="button1" VerticalAlignment="Bottom" Width="75" Click="button1_Click_1" />
    </Grid>
</Window>

窗口1 xaml

<Window x:Class="WpfApplication8.Window1"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="Window1" Height="119" Width="300" Name="UI">
    <StackPanel DataContext="{Binding ElementName=UI}">
        <TextBox Text="{Binding NewUser.TextA}" />
        <TextBox Text="{Binding NewUser.TextB}" />
        <Button Click="button1_Click" HorizontalAlignment="Right" Width="90" Height="30" Content="Add" />
    </StackPanel>
</Window>

窗口 1 代码

public partial class Window1 : Window, INotifyPropertyChanged
{
    private User _newUser = new User();
    public Window1()
    {
        InitializeComponent();
    }
    public User NewUser
    {
        get { return _newUser; }
        set { _newUser = value; NotifyPropertyChanged("NewUser"); }
    }
    private void button1_Click(object sender, RoutedEventArgs e)
    {
        DialogResult = true;
    }
    public event PropertyChangedEventHandler PropertyChanged;
    public void NotifyPropertyChanged(string property)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(property));
        }
    }
}

用户类

public class User : INotifyPropertyChanged
{
    private string _textA;
    private string _textB;
    public string TextA
    {
        get { return _textA; }
        set { _textA = value; NotifyPropertyChanged("TextA"); }
    }
    public string TextB
    {
        get { return _textB; }
        set { _textB = value; NotifyPropertyChanged("TextB"); }
    }
    public event PropertyChangedEventHandler PropertyChanged;
    public void NotifyPropertyChanged(string property)
    {
        if (PropertyChanged != null)
        {
            PropertyChanged(this, new PropertyChangedEventArgs(property));
        }
    }
}