Question

我想在我的应用程序中覆盖720和1080p的样式。现在我在我的页面.xaml文件中声明资源：

<phone:PhoneApplicationPage.Resources>
    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>
            <ResourceDictionary Source="../Styles/MapViewStyles.xaml" />
        </ResourceDictionary.MergedDictionaries>
    </ResourceDictionary>
</phone:PhoneApplicationPage.Resources>

我想在页面构造函数中重新定义样式，如下所示：

public MapView()
{
    InitializeComponent();

    if (ScreenSizeHelper.IsHd)
    {
        Resources.MergedDictionaries.Add(new ResourceDictionary { Source = new Uri("/App;component/Styles/MapViewStyles.Hd.xaml", UriKind.Relative)});
    }
}

我在调试中检查过，我的字典已添加到MergedDictionaries，但样式没有覆盖。如何刷新MergedDictionaries或重新初始化页面？

Answer 1

过了一会儿，我想出了一些有趣的解决方案。我创建了一个名为ResourceResolutionManager的特殊类：

public class ResourceResolutionManager
{
    public static DependencyProperty ResolutionProperty =
            DependencyProperty.RegisterAttached("Resolution", typeof(Resolutions?), typeof(ResourceResolutionManager),
                    new PropertyMetadata(null, ResolutionChanged));

    private static void ResolutionChanged(DependencyObject obj, DependencyPropertyChangedEventArgs e)
    {
        if (e.NewValue != null && (Resolutions)e.NewValue != ScreenExtension.CurrentResolution)
        {
            var dict = obj as ResourceDictionary;

            if (dict != null)
            {
                dict.Clear();
            }
        }
    }

    public static void SetResolution(DependencyObject obj, Resolutions? resolution)
    {
        obj.SetValue(ResolutionProperty, resolution);
    }

    public static Resolutions? GetResolution(DependencyObject obj)
    {
        return (Resolutions?)obj.GetValue(ResolutionProperty);
    }
}

我使用助手类确定屏幕分辨率：

public enum Resolutions { Wvga, Wxga, Hd };
public class ScreenExtension
{
    public static bool IsWvga
    {
        get
        {
            return Application.Current.Host.Content.ScaleFactor == 100;
        }
    }

    public static bool IsWxga
    {
        get
        {
            return Application.Current.Host.Content.ScaleFactor == 160;
        }
    }

    public static bool IsHd
    {
        get
        {
            return Application.Current.Host.Content.ScaleFactor == 150;
        }
    }

    public static Resolutions CurrentResolution
    {
        get
        {
            if (IsWvga) return Resolutions.Wvga;
            if (IsWxga) return Resolutions.Wxga;
            if (IsHd) return Resolutions.Hd;

            throw new InvalidOperationException("Unknown resolution");
        }
    }
}

我以这种方式在.xaml文件中使用ResourceResolutionManager：

<ResourceDictionary Source="Styles/Common.Hd.xaml">
    <core:ResourceResolutionManager.Resolution>
        <extensions1:Resolutions>Hd</extensions1:Resolutions>
    </core:ResourceResolutionManager.Resolution>
</ResourceDictionary>

在ResourceResolutionManager中，我检查ResourceDictionary中的解析匹配解析，如果不是，我清除ResourceDictionary。

如何在Windows Phone 8中覆盖不同分辨率的样式？

1 个答案: