Xamarin.forms 在平台上评估<；T>；

如果我使用代码从资源字典中检索到

OnPlatform

的实例，如何为当前平台评估它

public static string FontName =>
   ((OnPlatform<string>) Application.Current.Resources["Font"]) ...

公共静态字符串FontName=>
（（OnPlatform）Application.Current.Resources[“Font”]）。。。

您可以通过下一种方式实现：

<Application.Resources>
    <ResourceDictionary>
        <OnPlatform x:Key="MyPadding"
         x:TypeArguments="Thickness"
            iOS="0, 20, 0, 0"
            Android="0, 0, 0, 0"/>
    </ResourceDictionary>
</Application.Resources>

var thickness = (OnPlatform<Thickness>)Application.Current.Resources["MyPadding"];
var realThickness = (Thickness)thickness;

var thickness = Application.Current.GetResourceOnPlatform<Thickness>("MyPadding");

var thickness=（OnPlatform）Application.Current.Resources[“MyPadding”]；
var真实厚度=（厚度）厚度；

或

var thickness=（thickness）（OnPlatform）Application.Current.Resources[“MyPadding”]；

或者，您可以创建一个扩展方法：

public static class ApplicationExtensions
{
    public static T GetResourceOnPlatform<T>(this Application app, string key) => (T)(OnPlatform<T>)app.Resources[key];
}

公共静态类ApplicationExtensions
{
公共静态T GetResourceOnPlatform（此应用程序应用程序，字符串键）=>（T）（OnPlatform）应用程序资源[键]；
}

然后用下一种方式消费：

<Application.Resources>
    <ResourceDictionary>
        <OnPlatform x:Key="MyPadding"
         x:TypeArguments="Thickness"
            iOS="0, 20, 0, 0"
            Android="0, 0, 0, 0"/>
    </ResourceDictionary>
</Application.Resources>

var thickness = (OnPlatform<Thickness>)Application.Current.Resources["MyPadding"];
var realThickness = (Thickness)thickness;

var thickness = Application.Current.GetResourceOnPlatform<Thickness>("MyPadding");

var thickness=Application.Current.GetResourceOnPlatform（“MyPadding”）；