在后面的代码中再次调用 ObservableCollection 获取访问器

Question

是否可以再次调用ObservableCollectionget方法？我需要根据 ComboBox 选择更改 ItemsSource 所以我需要再次调用我的 ObservableCollection 这是我的代码

ObservableCollection<string> sampleData = new ObservableCollection<string>();
public ObservableCollection<string> SampleData
{
    get
    {
        if (sampleData.Count < 1)
            sampleData.Add(line);  

        return sampleData;
    }
}

上面的代码运行在应用程序崩溃时调用一次，但我需要在组合框更改时调用它

private void CmbFilter_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
    switch (cmbFilter.SelectedIndex)
    {
        case 0:         
            break;
        case 1:
            break;
        case 2:
            break;
        case 3:
            break;
    }
}

Answer 1

ObservableCollection 的全部要点是您不需要实施您在 SampleData getter 中建议的内容。您可以在此处采用 2 种方法：

利用ObservableCollection

请注意，这里有更好的选择，但超出了问题的范围。为 ComboBox.

查找 SelectedItem 绑定

private void CmbFilter_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
    // Modify your collection here based on what was selected.
}

忘了ObservableCollection

此方法需要您在 ViewModel class.

上实施 INotifyPropertyChanged

public IEnumerabe<string> SampleData
{
    get
    {
        // Return values based on the selection.
        if (SelectedData == "FirstValueICareAbout") // SelectedData assumes you have investigated how to bind to the SelectedItem of a ComboBox.
        {
            return new[]
            {
                "FirstValue",
                "SecondValue"
            };    
        }

        return Enumerable.Empty<string>();
    }
}

private void CmbFilter_SelectionChanged(object sender, SelectionChangedEventArgs e)
{
    // Notify the UI that SampleData has changed using INotifyPropertyChanged implementation.
    RaiseNotifyPropertyChanged(nameof(SampleData));
}

在后面的代码中再次调用 ObservableCollection 获取访问器

call ObservableCollection get accessor again in code behind

c#

wpf

observablecollection