加载DLL时的C#异常.找不到解决方案

以下代码：

foreach (var f in Directory.EnumerateFiles(startFolder,"*.dll",SearchOption.AllDirectories))
{
   try
   {
       var assembly = Assembly.LoadFrom(f);
       var types = assembly.GetTypes(); //exception raised here

       foreach (var type in types)
       {
            if (type.GetInterface("IPlayerFactory") != null)
                 instances.Add((IPlayerFactory)Activator.CreateInstance(type));
       }
       assembly = null;
    }
    catch (ReflectionTypeLoadException ex) { /* later,keep reading  */}

异常说：

An exception of type 'System.Reflection.ReflectionTypeLoadException' occurred in
mscorlib.dll but was not handled in user code

Additional information: Unable to load one or more of the requested types. Retrieve the    
LoaderExceptions property for more information.

我搜索了一下堆栈,找到了这个捕获器以寻找更多信息(来源：here)

捕获块：

catch (ReflectionTypeLoadException ex)
{
     StringBuilder sb = new StringBuilder();
     foreach (Exception exSub in ex.LoaderExceptions)
     {
          sb.AppendLine(exSub.Message);
          FileNotFoundException exFileNotFound = exSub as FileNotFoundException;
          if (exFileNotFound != null)
          {
              if (!string.IsNullOrEmpty(exFileNotFound.FusionLog))
              {
                  sb.AppendLine("Fusion Log:");
                  sb.AppendLine(exFileNotFound.FusionLog);
              }
          }
                    sb.AppendLine();
      }
      string errorMessage = sb.ToString();
      //Display or log the error based on your application.
      Console.WriteLine(sb);
 }

所以我设法提取：

'Battleships.Desktop.vshost.exe' (CLR v4.0.30319: Battleships.Desktop.vshost.exe):
 Loaded 'C:SomePathsome_dll.dll'. Cannot find
 or open the PDB file.
 A first chance exception of type 'System.Reflection.ReflectionTypeLoadException'  
 occurred in mscorlib.dll

我尝试了一些解决方案,但没有任
有什么好主意吗？