设置、设置设置和设置处理程序

Question

所以，回到这个问题，我构建了一组设置。现在，我正在努力清理整个系统。

这是abstract基类：

public class SettingChangedEventArgs : EventArgs
{
    public int NewSetting { get; private set; }

    public SettingChangedEventArgs(int newSetting)
    {
        NewSetting = newSetting;
    }
}

public abstract class ApplicationSettingsProvider
{
    public abstract int GetCurrentSetting();
    public abstract void SetCurrentSetting(int setting);

    public event EventHandler<SettingChangedEventArgs> SettingChanged;
    public void OnSettingChanged(int newSetting)
    {
        var handler = SettingChanged;
        if (handler != null)
        {
            handler(this, new SettingChangedEventArgs(newSetting));
        }
    }
}

下面是一个建立在它之上的设置：

public class ApplicationThemeProvider : ApplicationSettingsProvider
{
    public ApplicationThemeProvider()
    {
        ApplicationData.Current.DataChanged += (a, o) =>
        {
            CoreApplication.MainView.CoreWindow.Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () =>
            {
                OnSettingChanged((int)ApplicationData.Current.RoamingSettings.Values["Theme"]);
            });
        };
    }

    public override int GetCurrentSetting()
    {
        if (ApplicationData.Current.RoamingSettings.Values.ContainsKey("Theme"))
        {
            int value = (int)ApplicationData.Current.RoamingSettings.Values["Theme"];
            return (value >= 0 && value <= 2) ? value : 0;
        }
        return 0;
    }

    public override void SetCurrentSetting(int theme)
    {
        ApplicationData.Current.RoamingSettings.Values["Theme"] = theme;
        ApplicationData.Current.SignalDataChanged();
    }
}

我创建这样一个设置的实例：

private static ApplicationSettingsProvider _ThemeProvider = new ApplicationThemeProvider();
private static HomePageVM Data = new HomePageVM(_ThemeProvider);
private static Settings settings = new Settings(_ThemeProvider);

public MainPage()
{
    this.InitializeComponent();
    SettingsPane.GetForCurrentView().CommandsRequested += OnCommandsRequested;

    this.DataContext = Data;

    _ThemeProvider.SettingChanged += (s, e) => { Data.Theme = e.NewSetting; };
}

在settings SettingsPane中：

<StackPanel>
    <TextBlock FontSize="15" Margin="0,5">Text and background color:</TextBlock>
    <ComboBox Name="Theme" SelectionChanged="ThemeChanged">
        <ComboBoxItem Content="Black on White/Purple" Foreground="Black" Background="White"/>
        <ComboBoxItem Content="White on Black/White" Foreground="White" Background="Black"/>
        <ComboBoxItem Content="Black on White/Gold" Foreground="Black" Background="White"/>
    </ComboBox>
</StackPanel>

它的处理方式如下：

private ApplicationSettingsProvider _ThemeProvider;

public Settings(ApplicationSettingsProvider themeProvider)
{
    this.InitializeComponent();

    _ThemeProvider = themeProvider;

    InitSettings();
}

private void InitSettings()
{
    Theme.SelectedIndex = _ThemeProvider.GetCurrentSetting();
}

private void ThemeChanged(object sender, SelectionChangedEventArgs e)
{
    _ThemeProvider.SetCurrentSetting(Theme.SelectedIndex);
}

在我用于Page的VM中：

private ApplicationSettingsProvider _ThemeProvider;

private int _theme = 0;
public int Theme
{
    get { return _theme; }
    set
    {
        if (_theme != value)
        {
            _theme = value;
            OnPropertyChanged();
        }
    }
}

public HomePageVM(ApplicationSettingsProvider themeProvider)
{
    _ThemeProvider = themeProvider;

    Theme = _ThemeProvider.GetCurrentSetting();
}

这就是我在HomePage.xaml中使用它的方式：

<ListBox Name="Items" Grid.Column="0" Grid.RowSpan="2" ItemsSource="{Binding ItemList}" DisplayMemberPath="Title" SelectionChanged="OnSelectionChanged"
         Tapped="Items_Tapped" Margin="-2,-2,0,-2" KeyDown="ItemsKeyDown" Style="{Binding Theme, Converter={StaticResource LBStylePick}}"
         ItemContainerStyle="{Binding Theme, Converter={StaticResource LBIStylePick}}" Padding="0,10" SelectedItem="{Binding CurrentItem, Mode=TwoWay}" />

我创作的Converters是这样的：

<local:ThemeToLBStyleConverter x:Key="LBStylePick" />
<local:ThemeToLBIStyleConverter x:Key="LBIStylePick" />

C#：

public class ThemeToLBStyleConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, string language)
    {
        if ((int)value == 2) { return Application.Current.Resources["LBGold"]; }
        else if ((int)value == 1) { return Application.Current.Resources["LBDark"]; }
        else { return Application.Current.Resources["LBLight"]; }
    }

    public object ConvertBack(object value, Type targetType, object parameter, string language)
    {
        return new NotImplementedException();
    }
}

public class ThemeToLBIStyleConverter : IValueConverter
{
    public object Convert(object value, Type targetType, object parameter, string language)
    {
        if ((int)value == 2) { return Application.Current.Resources["LBIGold"]; }
        else if ((int)value == 1) { return Application.Current.Resources["LBIDark"]; }
        else { return Application.Current.Resources["LBILight"]; }
    }

    public object ConvertBack(object value, Type targetType, object parameter, string language)
    {
        return new NotImplementedException();
    }
}

这看起来相当复杂，尽管它工作得很好。此外，我不喜欢用普通的int来处理所有的主题值，enum看起来很整齐。我正在努力将ints改为enums，但在调整每一个使用它的东西之前，我想知道我是否应该以任何方式改变这个过程，这样我的所有工作都不会白费。

我的其他两种设置可以在提供的链接的PasteBin上查看。

Answer 1

• ThemeToLBStyleConverter和ThemeToLBIStyleConverter有相同的代码，除了方括号中的字符串。它们都应该是其他东西的子类，字符串作为成员。
• 在ApplicationThemeProvider中，您应该使用.TryGetValue()而不是.ContainsKey()和查找。