Xamarin.Plugins.Messaging无法发送带有附件的电子邮件

Question

我正在使用Xamarin.Plugins.Messaging nuget尝试发送带有附件的电子邮件。我遇到错误

  

Java.Lang.IllegalArgumentException：无法找到包含/data/data/com./files/Summary.pdf的已配置根目录

我已经按照说明设置了Android清单

 <application android:icon="@drawable/icon" android:largeHeap="@bool/largeheap" android:label="<MyAppName>">
<provider android:name="android.support.v4.content.FileProvider"
          android:authorities="com.<MyAppName>.fileprovider"
          android:exported="false"
          android:grantUriPermissions="true">
  <meta-data android:name="android.support.FILE_PROVIDER_PATHS" android:resource="@xml/file_paths"></meta-data>
</provider>

并将file_paths.xml文件集添加到Android资源

<paths xmlns:android="http://schemas.android.com/apk/res/android">
 <external-path name="external_files" path="." />
</paths>

这是我用来将字节数组保存为文件并将其附加到电子邮件中的代码

 var fileResult = await dal.getdoc(id); //REST call
 File.WriteAllBytes(Path.Combine(Xamarin.Essentials.FileSystem.AppDataDirectory, "BuyerSummary.pdf"), fileResult);
 string fileName = Path.Combine(Xamarin.Essentials.FileSystem.AppDataDirectory, "BuyerSummary.pdf");

   var email = new EmailMessageBuilder()

              .Subject("Buyer Netsheet summary")
              .Body(textSummary)
              .WithAttachment(fileName, "application/pdf")
              .Build();

            emailMessenger.SendEmail(email);