C#调用外部DLL无法捕获异常致崩溃，求解决方法

我正在开发一款使用无源码外部DLL进行驱动编程的应用。其中一个DLL内的读取驱动信息函数，在特定场景下会抛出NFCExceptionReadingFailure异常，导致应用崩溃。相关代码如下：

ReadbackFileAvailableEventArgs Driver_INFO;

public void HandleReadbackCompletedEvent(ReadbackFileAvailableEventArgs DINFO)
{
    Driver_INFO = DINFO;
}

public Tuple<string, string, string, string, string> getDriverINFO()
{
    // Unsubscribe first
    ReadbackCompletedEvent -= HandleReadbackCompletedEvent;
    // then Subscribe 
    ReadbackCompletedEvent += HandleReadbackCompletedEvent;

    //With this line of code reading process is started on the DLL ( ReadFromDevice is a method of the dll)
    ProgrammingAPI.ApplicationConstants.ReturnCode ret = ReadFromDevice();

    //ret is Success if the process is started on the DLL
    if (ret == ApplicationConstants.ReturnCode.Success)
    {
        Console.Write("\nREADING...");
        // wait for programming or readback completion
        while (ProgrammingAPI.ProgrammingAPI.IsWorking())
        {
            Console.Write(".");
            Thread.Sleep(500);
        }

        Console.Write("\READING OK");
        .......
    }
}

经排查，读取流程启动正常（ret返回Success），但执行过程中DLL抛出的异常仍会导致应用崩溃。将try-catch块加在ReadFromDevice()调用处或while循环内均无效，请问有办法处理该情况以避免应用崩溃吗？

针对外部DLL在后台线程抛出异常导致应用崩溃的情况，可尝试以下几种处理方式：

• 注册全局未捕获异常事件
  异常大概率是在DLL内部的后台线程抛出的，局部try-catch无法覆盖这类场景。可以在应用初始化阶段注册全局异常捕获事件，拦截未处理的异常：

  // 应用启动时添加
  AppDomain.CurrentDomain.UnhandledException += (sender, e) =>
  {
      var ex = e.ExceptionObject as Exception;
      if (ex != null && ex.GetType().Name == "NFCExceptionReadingFailure")
      {
          // 执行异常处理逻辑，比如记录日志、提示用户读取失败
          Console.WriteLine($"捕获到NFC读取异常: {ex.Message}");
          // 注意：该事件触发后默认会终止应用，部分场景可通过e.IsTerminating判断并做对应处理
      }
  };
  
  // 若是WinForms/WPF应用，额外注册线程异常事件
  Application.ThreadException += (sender, e) =>
  {
      if (e.Exception.GetType().Name == "NFCExceptionReadingFailure")
      {
          // 处理异常
          e.Handled = true;
      }
  };
  

• 将读取操作封装到独立AppDomain
  外部DLL的异常可能会污染当前应用域，你可以把读取逻辑放到单独的AppDomain中执行，即使该隔离域崩溃，主应用也能正常运行：

  public Tuple<string, string, string, string, string> getDriverINFO()
  {
      Tuple<string, string, string, string, string> result = null;
      AppDomain isolatedDomain = AppDomain.CreateDomain("IsolatedReadDomain");
      try
      {
          // 创建跨AppDomain调用的包装类实例
          var readerWrapper = (DriverReaderWrapper)isolatedDomain.CreateInstanceAndUnwrap(
              typeof(DriverReaderWrapper).Assembly.FullName,
              typeof(DriverReaderWrapper).FullName);
          result = readerWrapper.PerformRead();
      }
      catch (Exception ex)
      {
          if (ex.GetType().Name == "NFCExceptionReadingFailure")
          {
              Console.WriteLine("读取操作异常，已隔离处理");
          }
      }
      finally
      {
          AppDomain.Unload(isolatedDomain);
      }
      return result;
  }
  
  // 必须继承MarshalByRefObject以支持跨AppDomain调用
  public class DriverReaderWrapper : MarshalByRefObject
  {
      private ReadbackFileAvailableEventArgs Driver_INFO;
  
      public Tuple<string, string, string, string, string> PerformRead()
      {
          // 复制原读取逻辑
          ReadbackCompletedEvent -= HandleReadbackCompletedEvent;
          ReadbackCompletedEvent += HandleReadbackCompletedEvent;
  
          var ret = ReadFromDevice();
          if (ret == ApplicationConstants.ReturnCode.Success)
          {
              Console.Write("\nREADING...");
              while (ProgrammingAPI.ProgrammingAPI.IsWorking())
              {
                  Console.Write(".");
                  Thread.Sleep(500);
              }
              Console.Write("\READING OK");
              // 从Driver_INFO提取数据并返回结果
              return Tuple.Create(Driver_INFO.Field1, Driver_INFO.Field2, Driver_INFO.Field3, Driver_INFO.Field4, Driver_INFO.Field5);
          }
          return null;
      }
  
      private void HandleReadbackCompletedEvent(ReadbackFileAvailableEventArgs DINFO)
      {
          Driver_INFO = DINFO;
      }
  }
  

• 在回调方法内添加异常捕获
  检查ReadbackCompletedEvent的回调是否可能抛出异常，在HandleReadbackCompletedEvent中添加try-catch，拦截回调过程中触发的异常：

  public void HandleReadbackCompletedEvent(ReadbackFileAvailableEventArgs DINFO)
  {
      try
      {
          Driver_INFO = DINFO;
          // 若访问DINFO的属性也可能触发异常，需在此一并捕获
      }
      catch (Exception ex)
      {
          if (ex.GetType().Name == "NFCExceptionReadingFailure")
          {
              // 处理异常，比如重置Driver_INFO状态
              Driver_INFO = null;
          }
      }
  }
  

内容的提问来源于stack exchange，提问作者Simon3