C# 使用WPF和绑定单击时更改按钮背景色

我试图在单击时更改为按钮的颜色。它采用指定的初始颜色，但单击时不更新。我附加了我的代码，让我知道哪里出了问题。我试图实现下面文章中提供的代码

MainWindow.xaml代码段

<Window.Resources>
    <viewModels:MainWindowViewModel x:Key="MainViewModel"/>
</Window.Resources>

<Border Padding="20">
    <StackPanel DataContext="{Binding Source={StaticResource MainViewModel}}">
        <Button Content="Button1" Margin="10 10 10 10" Command="{Binding ClickCommand, Mode=OneWay}" Background="{Binding BackgroundColorBtn1}"/>
        <Button Content="Button2 " Margin="10 10 10 10"></Button>
    </StackPanel>
</Border>

</Window>

MainWindowViewModel.cs

public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();
            DataContext = new MainWindowViewModel();
        }

        private void MainWindow_OnLoaded(object sender, RoutedEventArgs e)
        {
            var desktopWorkingArea = System.Windows.SystemParameters.WorkArea;
            this.Left = desktopWorkingArea.Right - this.Width;
            this.Top = desktopWorkingArea.Bottom - this.Height;
        }
    }

namespace DockedPanel.ViewModels
{
    public class MainWindowViewModel:INotifyPropertyChanged
    {
        public event PropertyChangedEventHandler PropertyChanged;
        public MainWindowViewModel()
        {
            _canExecute = true;
        }
        private ICommand _clickCommand;
        public ICommand ClickCommand
        {
            get
            {
                return _clickCommand ?? (_clickCommand = new CommandHandler(() => MyAction(), _canExecute));
            }
        }
        private bool _canExecute;
        public void MyAction()
        {
            _backgroundColorBtn1 = Colors.Blue;
        }

        private void OnPropertyChanged(string propertyName)
        {
            PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
        }

        private Color _backgroundColorBtn1 =  Colors.White;
        public Color BackgroundColorBtn1
        {
            get { return _backgroundColorBtn1; }
            set
            {
                if (value == _backgroundColorBtn1)
                    return;

                _backgroundColorBtn1 = value;

                OnPropertyChanged(nameof(BackgroundColorBtn1));
            }
        }
    }
}

最后 CommandHandler

namespace DockedPanel.ViewModels.Command
{
    public class CommandHandler : ICommand
    {
        private Action _action;
        private bool _canExecute;
        public CommandHandler(Action action, bool canExecute)
        {
            _action = action;
            _canExecute = canExecute;
        }

        public bool CanExecute(object parameter)
        {
            return _canExecute;
        }

        public event EventHandler CanExecuteChanged;

        public void Execute(object parameter)
        {
            _action();
        }
    }
}

---

您需要在BackgroundColorBtn1属性上调用OnPropertyChanged，因为您正在更改私有备份变量，并且需要通知视图

您可以按如下方式修改MyAction方法

 public void MyAction()
 {
      _backgroundColorBtn1 = Colors.Blue;
      OnPropertyChanged(nameof(BackgroundColorBtn1));
 }

public class ColorToSolidColorBrushValueConverter : IValueConverter 
{

    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        if (value == null)
            return null;

        if (value is Color)
            return new SolidColorBrush((Color)value);

        throw new InvalidOperationException("Unsupported type [" + value.GetType().Name + "], ColorToSolidColorBrushValueConverter.Convert()");
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
   {
        throw new NotImplementedException();
    }
}

或者，您可以直接设置属性而不是backing字段，后者将调用OnPropertyChanged调用本身

 public void MyAction()
 {
      BackgroundColorBtn1 = Colors.Blue;
 }

您还需要使用颜色到笔刷转换器。按钮的背景属性接受笔刷，而不是颜色。转换器将允许您将所选颜色转换为笔刷

您可以如下定义转换器

 public void MyAction()
 {
      _backgroundColorBtn1 = Colors.Blue;
      OnPropertyChanged(nameof(BackgroundColorBtn1));
 }

public class ColorToSolidColorBrushValueConverter : IValueConverter 
{

    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
        if (value == null)
            return null;

        if (value is Color)
            return new SolidColorBrush((Color)value);

        throw new InvalidOperationException("Unsupported type [" + value.GetType().Name + "], ColorToSolidColorBrushValueConverter.Convert()");
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
   {
        throw new NotImplementedException();
    }
}

然后，你可以把它当作

Background="{Binding BackgroundColorBtn1, Converter={StaticResource colorToSolidColorBrushConverter}}"

请确保在使用资源部分之前已将以下内容添加到资源部分

<Window.Resources>
<ResourceDictionary>
        <myNameSpace:ColorToSolidColorBrushValueConverter  x:Key="colorToSolidColorBrushConverter"/>
</ResourceDictionary>
</Window.Resources>

设置属性而不是备份字段可能更好。属性的setter已经具备了引发属性更改通知的所有必要逻辑…@elgonzo yes。我会在回答时提到同样的问题。自从他使用了Private field后，他已经回答了有关它的问题，并想指出问题的原因。谢谢@Anu Viswan，我尝试了两种方法，但单击后仍然没有变为蓝色。@ManojPathak我已经更新了我的答案，请您检查一下，您也缺少了一个颜色到笔刷的转换器