Xamarin.Forms.Xaml.XamlParseException：未找到用于 trans 的 MarkupExtension：在发布模式下使用 PCL 进行翻译

Question

我非常渴望找到解决以下问题的方法。

我有一个包含 4 个项目的跨平台解决方案，

3 操作系统细节
MyApp.android,
MyApp.Winphone,
MyApp.IOS
和一个 PCL 项目
MyApp.BLL

在 MyApp.BLLbll 中，我使用的是 MyApp 命名空间，在根目录中我有类 TranslateExtension.cs

namespace MyApp
{
    [ContentProperty("Text")]
    public class TranslateExtension: IMarkupExtension

{
    readonly CultureInfo ci;
    const string ResourceId = "MyApp.Resources.AppResource";

    public TranslateExtension()
    {
        ci = DependencyService.Get<ILocalize>().GetCurrentCultureInfo();
    }

    public string Text { get; set; }

    public object ProvideValue(IServiceProvider serviceProvider)
    {
        if (Text == null)
            return "";

        ResourceManager resmgr = new ResourceManager(ResourceId
                            , typeof(TranslateExtension).GetTypeInfo().Assembly);

        var translation = resmgr.GetString(Text, ci);
        try
        {
        if (translation == null)
            {
#if DEBUG
                throw new ArgumentException(
                    String.Format("Key '{0}' was not found in resources '{1}' for culture '{2}'.", Text, ResourceId, ci.Name),
                    "Text");
#else
                translation = Text; // HACK: returns the key, which GETS DISPLAYED TO THE USER
#endif
            }
        }
        catch (Exception exp) {
        }
        return translation;
    }
}

在 Xamarin 表单中，我使用以下内容来启用标签等的翻译。

<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             x:Class="MyApp.Views.RegisterWebServiceXaml"
             xmlns:trans="clr-namespace:MyApp;assembly=MyApp.BLL"
             IsBusy="{Binding IsWorking}"
             >

  <ContentPage.Content>
    <StackLayout Orientation="Vertical" VerticalOptions="FillAndExpand" Padding="0,75,0,0">
          <Entry Text="{Binding Path=OrganizationId, Mode=TwoWay}" Placeholder="{trans:Translate OrganizationId}" Style="{StaticResource LoginStyle}" />
          ...
          <Label Text="{trans:TranslateUpper Next}" x:Name="LoginLabel" HorizontalOptions="Center" Style="{StaticResource BasicLabel}" />
    </StackLayout>
  </ContentPage.Content>
</ContentPage>

这使用调试模式就像一个魅力，但是当我尝试在发布模式下为 Android 编译解决方案时，我的应用程序在加载显示“MyApp 已停止”的启动画面后突然停止

查看应用程序输出，我可以找到以下错误消息：

[Xamarin.Insights] Warning: Unhandled exception: Xamarin.Forms.Xaml.XamlParseException: MarkupExtension not found for trans:Translate
[Xamarin.Insights] at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () <0x00028>
[Xamarin.Insights] at System.Runtime.CompilerServices.AsyncMethodBuilderCore.<ThrowAsync>m__0 (object) <0x0003f>
[Xamarin.Insights] at Android.App.SyncContext/<Post>c__AnonStorey0.<>m__0 () <0x00027>
[Xamarin.Insights] at Java.Lang.Thread/RunnableImplementor.Run () <0x0003f>
[Xamarin.Insights] at Java.Lang.IRunnableInvoker.n_Run (intptr,intptr) <0x0003b>
[Xamarin.Insights] at (wrapper dynamic-method) object.44dc0140-8f03-4bf1-a261-186aa2a7ef42 (intptr,intptr) <0x0003b>
[art] JNI RegisterNativeMethods: attempt to register 0 native methods for md52ce486a14f4bcd95899665e9d932190b.JavaProxyThrowable
[AndroidRuntime] Shutting down VM
[AndroidRuntime] FATAL EXCEPTION: main
[AndroidRuntime] Process: MyApp.MyApp, PID: 32091
[AndroidRuntime] java.lang.RuntimeException: java.lang.reflect.InvocationTargetException
[AndroidRuntime]    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1184)
[AndroidRuntime] Caused by: java.lang.reflect.InvocationTargetException
[AndroidRuntime]    at java.lang.reflect.Method.invoke(Native Method)
[AndroidRuntime]    at java.lang.reflect.Method.invoke(Method.java:372)
[AndroidRuntime]    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1389)
[AndroidRuntime]    ... 1 more
[AndroidRuntime] Caused by: md52ce486a14f4bcd95899665e9d932190b.JavaProxyThrowable: Xamarin.Forms.Xaml.XamlParseException: MarkupExtension not found for trans:Translate
[AndroidRuntime] at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw () <0x00028>
[AndroidRuntime] at System.Runtime.CompilerServices.AsyncMethodBuilderCore.<ThrowAsync>m__0 (object) <0x0003f>
[AndroidRuntime] at Android.App.SyncContext/<Post>c__AnonStorey0.<>m__0 () <0x00027>
[AndroidRuntime] at Java.Lang.Thread/RunnableImplementor.Run () <0x0003f>
[AndroidRuntime] at Java.Lang.IRunnableInvoker.n_Run (intptr,intptr) <0x0003b>
[AndroidRuntime] at (wrapper dynamic-method) object.44dc0140-8f03-4bf1-a261-186aa2a7ef42 (intptr,intptr) <0x0003b>
[AndroidRuntime] 
[AndroidRuntime]    at mono.java.lang.RunnableImplementor.n_run(Native Method)
[AndroidRuntime]    at mono.java.lang.RunnableImplementor.run(RunnableImplementor.java:29)
[AndroidRuntime]    at android.os.Handler.handleCallback(Handler.java:739)
[AndroidRuntime]    at android.os.Handler.dispatchMessage(Handler.java:95)
[AndroidRuntime]    at android.os.Looper.loop(Looper.java:145)
[AndroidRuntime]    at android.app.ActivityThread.main(ActivityThread.java:5944)
[AndroidRuntime]    ... 4 more

有没有机构可以解决这个问题？我找不到它。我尝试过使用多个命名空间（ MyApp.android、MyApp、MyApp.BLL、MyApp.MyApp ），但直到现在我还没有找到合适的命名空间。

为什么它在调试模式下工作，而不是在发布/应用商店模式下工作？

Answer 1

检查项目设置，确保链接已关闭或 SDK-ony .

如果它是“链接所有程序集”并且没有它，您的代码会变得太大，您可能希望在您的类上使用 [Preserve] 属性。

有关 Xamarin 链接器的详细信息，请参阅 this page