.net条件无法正确评估

  var assmSpec = util.ASSEMBLYFOLDER + task.AssemblyName; // evals to valid fileSpec
  if (!File.Exists(assmSpec))
      throw new TaskException(string.Format(
          \"Assembly [{0}] cannot be located.\", assmSpec));

File.Exists()

  var assmSpec = util.ASSEMBLYFOLDER + task.AssemblyName; // evals to valid fileSpec
  var asmExists = File.Exists(assmSpec);
  if (!asmExists)
      throw new TaskException(string.Format(
          \"Assembly [{0}] cannot be located.\", assmSpec));

  var assmSpec = util.ASSEMBLYFOLDER + task.AssemblyName; // evals to valid fileSpec
  if (!File.Exists(assmSpec) && File.Exists(assmSpec))
      throw new TaskException(string.Format(
         \"Assembly [{0}] cannot be located.\", assmSpec));

  public void StartProcess(Task task)
    {
        log.Write(log.Level.Debug, string.Format(
            \"TaskWorker.StartProcess {0} process\",
            task.Name), task.Name);
        WorkerMessageManager.MsgArrvdWorkerHndlr += MsgArrvdWorkerHndlr;
        var tskName = task.Name;
        var assmSpec = util.ASSEMBLYFOLDER + task.AssemblyName;
        if (!File.Exists(assmSpec))
            throw new TaskException(string.Format(
                \"Assembly [{0}] cannot be located.\", assmSpec));

        try
        {
            WorkerMessageManager.NotifyWorker(new ProgressTaskMessage(
                                    tskName, \"\", tskName + \"  starting...\"));
            // -------------------------------------------
            Assembly dA;
            try { dA = Assembly.LoadFrom(assmSpec); }
            catch(FileNotFoundException nfX)
            { throw new TaskException(string.Format(
                \"Assembly [{0}] cannot be located.\", assmSpec), 
                nfX); }
            // -------------------------------------------
            var iTsk = (IExecuteTasks)dA.CreateInstance(task.ClassName);
            if (iTsk == null)
                throw new TaskException(
                    string.Format(\"Unable to instantiate {0} from {1}\",
                        task.ClassName, task.AssemblyName));

            if (iTsk.TaskName != tskName) // do not execute if names do not match
                throw new TaskNameMismatchException(string.Format(
                    \"CHECK CONFIGURATION SETTINGS,  Data Task Name Mismatch.{0}\" +
                    \"Task name defined in TaskScheduler.config [{1}], {0} does \" +
                    \"not match name [{2}] as defined in Task Logic assembly: {3}.{4}\",
                        sNL, tskName, iTsk.TaskName, task.AssemblyName, 
                        task.ClassName),  tskName, iTsk.TaskName);
            // -------------------------------------------
            iTsk.DataImportProgressEvent += OnProgressReport;
            iTsk.ProcessCompletedEvent += OnProcessCompleted;
            iTsk.GeneralEvent += OnGeneralEvent;
            // -----------------------------------
            log.Write(log.Level.Debug, string.Format(
                  \"{0} process Started\", task.Name),
                  task.Name);
            if (task.JobQueue.HasJobReady)
                iTsk.StartTask(JobQueues.Instance.DeQueue(tskName));
            else iTsk.StartTask(); 
            log.Write(log.Level.Debug, string.Format(
                  \"{0} process Completed\", task.Name),
                  task.Name);
        }
        catch (TaskNameMismatchException inmX)
        { log.Write(log.Level.Warn, inmX.Message, tskName, inmX); }

        catch (BpaTaskException mX)
        {
            var errMsg = string.Format(
                \"Error in Data Import StartProcess(). \" + sNL +
                \"Exception {0}: {1}, \" + sNL +
                \"Stack Trace: {2}\",
                mX, mX.Message, mX.StackTrace); 
            log.Write(log.Level.Error, errMsg, 
                        task.Name, mX);
        }

        catch(Exception X)
        {
            var errMsg = string.Format(
                \"Error in Data Import StartProcess(). \" + sNL +
                \"Exception {0}: {1}, \" + sNL +
                \"Stack Trace: {2}\",
                X, X.Message, X.StackTrace);
            log.Write(log.Level.Error, errMsg, task.Name, X);

            // WorkerMessageManager.NotifyWorker(new ImportFailMessage(X));
            // This throw instruction causes the Scheduler service to stop alltogether
            // I\'m Removing the throw for now, because it seems inappropriate to 
            //          kill the whole service..
            throw;
        }

        finally
        {
            task.IsRunning = false;
            WorkerMessageManager.MsgArrvdWorkerHndlr -= MsgArrvdWorkerHndlr;
        }
    }