如何将timer_ticker设置为休眠，直到在后台完成该过程

Question

我的timerTick（）有问题，因为它每0.5秒执行一次，对我来说没问题，因为他每0.5秒检查一次connectetCard（），现在如果这样，他应该将它分配给_bw.DoWork中我分配给我的5秒运行时，如何将timerTick（）再次触发，但仅在backgroundWorker中的进程完成时才能触发。

这是我的代码：

public FormMenu()
        {
            InitializeComponent();

            SelectDevice();
            establishContext();
            timerBatch.Start();
            _bw = new BackgroundWorker
            {
                WorkerReportsProgress = true,
                WorkerSupportsCancellation = true
            };

        }   

private void timerBatch_Tick(object sender, EventArgs e)
        {
            if (connectCard())
            {
                cardUID = getcardUID();
                if (cardUID != "Error")
                {
                    using (DBEntities db = new DBEntities())
                    {
                        try
                        {
                            personData = db.Persons.Where(x => x.BATCH_ID == cardUID).FirstOrDefault();
                            if (maDaten == null)
                            {
                                labelInfo.Text = "Batch invalid.";
                                return;
                            }
                            else
                            {
                                person = db.Person.Where(x => x.LPE_ID == personData.MA_ID).FirstOrDefault();
                                _bw.DoWork += _bw_DoWork;
                                _bw.ProgressChanged += bw_ProgressChanged;
                                _bw.RunWorkerCompleted += bw_RunWorkerCompleted;
                                _bw.RunWorkerAsync();
                            }                         
                        }
                        catch (Exception es)
                        {
                            MessageBox.Show(es.Message);
                        }

                    };
                }
            }
        }

  private void _bw_DoWork(object sender, DoWorkEventArgs e)
        {
            for (int i = 5; i >= 0; i -= 1)
            {
                if (_bw.CancellationPending) { 
                    e.Cancel = true; return; 
                }
                if (i == 0)
                {
                    e.Cancel = true; return;
                }
                _bw.ReportProgress(i);
                Thread.Sleep(1000);
            }            
        }

   private void bw_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {
            labelInfo.Text = "Hello " + person.FirstName + " " + person.LastName + " " + e.ProgressPercentage.ToString();

        }

  private void bw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            labelInfo.Text = labelInfo.Text.Trim();
        }

Answer 1

尝试这样的事情：

public FormMenu()
        {
            InitializeComponent();

            SelectDevice();
            establishContext();
            timerBatch.Start();
            _bw = new BackgroundWorker
            {
                WorkerReportsProgress = true,
                WorkerSupportsCancellation = true
            };

        }   

//CHANGE:
bool backgroundworkerRunning = false;

private void timerBatch_Tick(object sender, EventArgs e)
        {
            //CHANGE:
            if (backgroundworkerRunning)
              return;

            if (connectCard())
            {
                cardUID = getcardUID();
                if (cardUID != "Error")
                {
                    using (DBEntities db = new DBEntities())
                    {
                        try
                        {
                            personData = db.Persons.Where(x => x.BATCH_ID == cardUID).FirstOrDefault();
                            if (maDaten == null)
                            {
                                labelInfo.Text = "Batch invalid.";
                                return;
                            }
                            else
                            {
                                person = db.Person.Where(x => x.LPE_ID == personData.MA_ID).FirstOrDefault();
                                _bw.DoWork += _bw_DoWork;
                                _bw.ProgressChanged += bw_ProgressChanged;
                                _bw.RunWorkerCompleted += bw_RunWorkerCompleted;
                                //CHANGE:
                                backgroundworkerRunning = true; 
                                _bw.RunWorkerAsync();
                            }                         
                        }
                        catch (Exception es)
                        {
                            MessageBox.Show(es.Message);
                        }

                    };
                }
            }
        }

  private void _bw_DoWork(object sender, DoWorkEventArgs e)
        {
            for (int i = 5; i >= 0; i -= 1)
            {
                if (_bw.CancellationPending) { 
                    e.Cancel = true; return; 
                }
                if (i == 0)
                {
                    e.Cancel = true; return;
                }
                _bw.ReportProgress(i);
                Thread.Sleep(1000);
            }            
        }

   private void bw_ProgressChanged(object sender, ProgressChangedEventArgs e)
        {
            labelInfo.Text = "Hello " + person.FirstName + " " + person.LastName + " " + e.ProgressPercentage.ToString();

        }

  private void bw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            //CHANGE:
            backgroundworkerRunning = false; 
            labelInfo.Text = labelInfo.Text.Trim();
        }