c# - Context.GetExternalFilesDir() 不接受 null

Question

我正在尝试获取我的 c# xamarin android 应用程序的私有(private)外部存储目录的路径。微软文档告诉我们使用

Android.Content.Context.GetExternalFilesDir(string)

但是，当我尝试使用这个函数时，我收到关于该函数的以下错误:

An object reference is required for the non-static field, method or property

这是我的代码

class RecorderController {
    string externalStoragePath;

    public RecorderController() {
        externalStoragePath = Path.Combine(Context.GetExternalFilesDir(null), "recordings");
     
     // I have also tried the following:
     // string s = null;
     // externalStoragePath = Path.Combine(Context.GetExternalFilesDir(s), "recordings");

     // Even when I try to get the path to the Downloads folder, I get the same error:
     // string s = Android.OS.Environment.DirectoryDownloads;
     // externalStoragePath = Path.Combine(Context.GetExternalFilesDir(s), "recordings");
    }
}

我不知道如何解决这个问题，有人知道我做错了什么吗？

Answer 1

努力改变

externalStoragePath = Path.Combine(Context.GetExternalFilesDir(null), "recordings");

到

externalStoragePath = Path.Combine(GetExternalFilesDir(null).AbsolutePath, "recordings");