当用户更改 WPF 中的组合框时，SelectionChanged 未触发

Question

所以我的 selectionChanged 事件不会在用户更改时触发，但如果我在代码中更改它就会触发。

我正在使用 selectionchanged 从一个组合框中进行选择以填充另一个组合框。

<!--1st list -->
<ComboBox ItemsSource="{Binding djurKatList}" SelectedItem="{Binding SelectedDjurKat}" SelectionChanged="listKat_SelectionChanged" x:Name="listKat" HorizontalAlignment="Left" Margin="98,118,0,0" VerticalAlignment="Top" Width="120"/>

<!--2nd list that's filled after something is selected in 1st list-->
<ComboBox ItemsSource="{Binding djurArtList}" SelectedItem="{Binding SelectedDjurArt}" x:Name="listDjur" HorizontalAlignment="Left" Margin="98,154,0,0" VerticalAlignment="Top" Width="120"/>

这背后的代码填充了第二个组合框，并且在我更改第一个组合框时未执行：

private void listKat_SelectionChanged(object sender, SelectionChangedEventArgs e)
{            
    fyllDjurArtLista(hanterare, typeof(Daggdjur));
}

当我在代码中更改选择时，selectionChanged 触发，在下面我更改我选择的 comboboxitem，事件被触发，第二个组合框被填充。

var listItem = new ComboBoxItem { Content = "Välj kategori" };
SelectedDjurKat = listItem;

Answer 1

这是一个简单的例子，它可以工作。

/// <summary>
/// Interaction logic for MainWindow.xaml
/// </summary>
public partial class MainWindow : Window {
    public MainWindow() {
        InitializeComponent();

        VM v = new VM();
        v.djurKatList = new List<string>();
        v.djurKatList.Add("1");
        v.djurKatList.Add("2");
        v.djurKatList.Add("3");
        v.djurKatList.Add("4");
        v.djurKatList.Add("5");

        DataContext = v;
    }

    private void listKat_SelectionChanged(object sender, SelectionChangedEventArgs e) {
       // fyllDjurArtLista(hanterare, typeof(Daggdjur));
    }
}

public class VM {
    public List<string> djurKatList { get; set; }
    public string SelectedDjurKat { get; set; }
}

<Window x:Class="WpfApplication1.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow" Height="350" Width="525">
<Grid>
    <StackPanel>
        <!--1st list -->
        <ComboBox ItemsSource="{Binding djurKatList}" SelectedItem="{Binding SelectedDjurKat}" SelectionChanged="listKat_SelectionChanged"
                  x:Name="listKat" HorizontalAlignment="Left" Margin="98,118,0,0" VerticalAlignment="Top" Width="120"/>

        <!--2nd list that's filled after something is selected in 1st list-->
        <ComboBox ItemsSource="{Binding djurArtList}" SelectedItem="{Binding SelectedDjurArt}" x:Name="listDjur" HorizontalAlignment="Left"
                  Margin="98,154,0,0" VerticalAlignment="Top" Width="120"/>
    </StackPanel>
</Grid>

SelectionChanged 已触发。但是，如果问题是另一个组合框未填充，那么您需要按照建议使用 INotifyPropertyChanged。您需要为属性 djurArtList 调用 PropertyChanged。

当用户更改 WPF 中的组合框时，SelectionChanged 未触发

SelectionChanged isn't firing when user changes combobox in WPF

c#

wpf

events