上传文件并发送到服务层,即c#类库

我正在尝试上传文件并将其发送到服务层进行保存,但是我一直在寻找控制器如何获取HTTPPostedFileBase并将其直接保存在控制器中的示例.我的服务层在web dll上没有依赖关系,因此我需要将我的对象读入内存流/字节吗？关于我应该怎么做的任何指示非常感谢…

注意：文件可以通过pdf,word,所以我可能还需要检查内容类型(可能在域服务层…

码：

public ActionResult UploadFile(string filename,HttpPostedFileBase thefile)
{
//what do I do here...?


}

编辑：

public interface ISomethingService    
{
  void AddFileToDisk(string loggedonuserid,int fileid,UploadedFile newupload);    
}
    public class UploadedFile
    {
        public string Filename { get; set; }
        public Stream TheFile { get; set; }
        public string ContentType { get; set; }
    }

public class SomethingService : ISomethingService    
{
  public AddFileToDisk(string loggedonuserid,UploadedFile newupload)
  {
    var path = @"c:somewhere";
    //if image
     Image _image = Image.FromStream(file);
     _image.Save(path);
    //not sure how to save files as this is something I am trying to find out...
  } 
}

public ActionResult UploadFile(string filename,HttpPostedFileBase thefile)
{
    if (thefile != null && thefile.ContentLength > 0)
    {
        byte[] buffer = new byte[thefile.ContentLength];
        thefile.InputStream.Read(buffer,buffer.Length);
        _service.SomeMethod(buffer,thefile.ContentType,thefile.FileName);
    }
    ...
}