如何在 Windows 通用应用程序中在运行时访问和更改资源字典中资源的值?

我正在将我的 Windows Phone 8 应用程序迁移到 Windows 通用应用程序.我在 Windows 8.1 项目中创建了一个具有一些值的资源字典，并将其路径包含在 App.xaml 文件中.下面是资源字典和App.xaml.

I am migrating my Windows Phone 8 App to Windows Universal Apps. I have created a Resource Dictionary with some values in Windows 8.1 project and included its path in App.xaml file. Below is Resource Dictionary and App.xaml.

资源字典

<ResourceDictionary
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:MyApp.Styles">

<SolidColorBrush Color="#388941"
                 x:Key="AppBackGroundColor" />
<SolidColorBrush Color="White"
                 x:Key="PageTitleColor" />
<SolidColorBrush Color="White"
                 x:Key="AppFontColor" />
<SolidColorBrush Color="White"
                 x:Key="StatusColor" />
</ResourceDictionary>

应用程序.xaml

<Application
x:Class="MyCouncilServices.App"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:MyApp">

<Application.Resources>
    <!-- Application-specific resources -->
    <ResourceDictionary>
        <ResourceDictionary.MergedDictionaries>

            <!-- 
                Styles that define common aspects of the platform look and feel
                Required by Visual Studio project and item templates
             -->
            <ResourceDictionary Source="/Styles/Styles.xaml"/>

        </ResourceDictionary.MergedDictionaries>
    </ResourceDictionary>
</Application.Resources>

现在，我想知道如何在整个应用程序中访问这些值并在 c# 代码中更改其值.

Now, I want to know how can I access this values in whole App and change its value in c# code.

我尝试了与我在 Windows Phone 8 项目中所做的相同的方法，如下所示，但它导致了 System.Argument 异常.

I tried the same way as I did in Windows Phone 8 project as below but it was causing System.Argument Exception.

if(App.Current.Resources.ContainsKey("AppBackGroundColor"))
  {                      App.Current.Resources.Remove("AppBackGroundColor");
   }             App.Current.Resources.Add("AppBackGroundColor",GetColorFromHex(#FFFFFF));//Getting error at this line.System.ArgumentException ("An item with the same key has already been added.")

我想在我的整个应用程序中使用资源.

I want to use the Resources in my entire app.

请谁能建议我们如何从 Dictionary 访问资源并更改其值.

Please can anyone suggest how can we access the resources from Dictionary and change its values.