用户控件绑定未返回正确的值

这里有太多错误，向您展示正确的代码比解释所有内容更容易。阅读我上面链接的文章并研究这段代码。我还没有完全按照我的方式重新设计：例如，没有主视图模型。现在这不是 MVVM 的一个很好的示例，但它说明了您在网格中放置了哪些内容、如何编写模板列以及如何正确更新属性。首先，您使用用户控件的实例作为同一控件的视图模型，但它并不是真正的视图模型，因为它从不引发任何属性更改通知。让我们为网格编写一个实际的项目视图模型。这不是 UI 控件。它是数据，将显示在UI 控件中。它拥有信息，并且当信息发生变化时它会收到通知。如果你愿意的话，它也可以有一些逻辑。public class SliderItem : ObservableObject{ public SliderItem() { } public SliderItem(int trans, int rot, int scale) { Translation = trans; Rotation = rot; Scale = scale; } public void UpdateValues(int newTrans, int newRot, int newScale) { Translation = newTrans; Rotation = newRot; Scale = newScale; } public void UpdateDescription(string newText) { if(!String.IsNullOrWhiteSpace(newText)) { Description = newText; OnPropertyChanged(nameof(Description)); } } public String Description { get; private set; } private int _translation = 0; public int Translation { get { return _translation; } set { if (value != _translation) { _translation = value; OnPropertyChanged(nameof(Translation)); } } } private int _rotation = 0; public int Rotation { get { return _rotation; } set { if (value != _rotation) { _rotation = value; OnPropertyChanged(nameof(Rotation)); } } } private int _scale = 0; public int Scale { get { return _scale; } set { if (value != _scale) { _scale = value; OnPropertyChanged(nameof(Scale)); } } }}TripleSlider.xamlTripleSlider 的 XAML 基本上没问题；主要问题是它正在寻找以前不存在的视图模型。但我们还希望滑块值绑定在Value更改时更新绑定属性，而不是在滑块控件失去焦点时（这是不明显的默认行为）。因此，添加UpdateSourceTrigger=PropertyChanged到所有三个 Slider.Value 绑定。 Value="{Binding Path=Translation, UpdateSourceTrigger=PropertyChanged}" TripleSlider.xaml.cs就是这个。这就是该类应该的样子。public partial class TripleSlider : UserControl{ public TripleSlider() { InitializeComponent(); }}MainWindow.xaml 没问题。MainWindow.xaml.cs 做了一些更改：public partial class MainWindow : Window{ // Don't use arrays. Use ObservableCollection<WhateverClass> for binding to UI controls, // use List<Whatever> for anything else. private ObservableCollection<SliderItem> _sliders = new ObservableCollection<SliderItem>(); public MainWindow() { InitializeComponent(); // The ObservableCollection will notify the grid when you add or remove items // from the collection. Set this and forget it. Everywhere else, interact with // _sliders, and let the DataGrid handle its end by itself. // Also get rid of EnableRowVirtualization="False" from the DataGrid. Let it // virtualize. myDataGrid.ItemsSource = _sliders; } private void BAddControls_Click(object sender, RoutedEventArgs e) { for (int i = 0; i < 49; i++) { var newSlider = new SliderItem(); newSlider.UpdateDescription(String.Format("{0}: Unkown Value", (i+1))); newSlider.UpdateValues((i+1)*1337, (i+1)*1337, (i+1)*1337); _sliders.Add(newSlider); } bAddControls.IsEnabled = false; } private void BFetchValues_Click(object sender, RoutedEventArgs e) { if (myDataGrid.SelectedItem != null) { var selectedSlider = myDataGrid.SelectedItem as SliderItem; MessageBox.Show(String.Format("Translation: {0}\nRotation: {1}\nScale: {2}", selectedSlider.Translation, selectedSlider.Rotation, selectedSlider.Scale), "Information", MessageBoxButton.OK, MessageBoxImage.Information); } } private void MyDataGrid_SelectionChanged(object sender, SelectionChangedEventArgs e) { bFetchValues.IsEnabled = (myDataGrid.SelectedItem != null) ? true : false; }}

用户控件绑定未返回正确的值

1回答