DoWork完成后未呼叫后臺作業人員RunWorkerCompleted

我正在創建一個簡單的程式來 ping 我們網路上的所有服務器并回傳 ping 請求是否成功。

我正在嘗試利用后臺作業人員，以便用戶可以按下 ping 按鈕并且 ping 在后臺運行，同時他們可以在 UI 上執行其他操作

DoWork 運行良好，沒有回圈讓它無限地保持在那里，它到達了這條線：

r = pinger.Send(s)

然后根據我的理解它結束了，所以應該呼叫 RunWorkCompleted 方法？

經過長時間的缺勤后，我正在重新學習編程，所以如果我錯過了一些明顯的東西，我很抱歉......

   public Form1()
    {

        InitializeComponent();
        backgroundWorker1.WorkerReportsProgress = true;
        backgroundWorker1.WorkerSupportsCancellation = true;
        backgroundWorker1.DoWork  = new DoWorkEventHandler(backgroundWorker1_DoWork);
    }

    private void Ping_Btn_Click(object sender, EventArgs e)
    {

        count = Convert.ToInt32(pingSeconds_TxtBox.Text);

        if (backgroundWorker1.IsBusy != true)
        {
            // Start operation
            backgroundWorker1.RunWorkerAsync();
        }
       
    }

    private static void OnTimedEvent(Object source, ElapsedEventArgs e)
    {
        BackgroundWorker worker = new BackgroundWorker();
        worker.WorkerSupportsCancellation = true;
    }

    private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
    {
        BackgroundWorker worker = sender as BackgroundWorker;

        if(worker.CancellationPending == true)
        {
            e.Cancel = true;
        }
        else
        {
            for(int i = 0; i <= count; i  )
            {
                MessageBox.Show("something is happening");
                // Create ping object
                Ping pinger = new Ping();
                PingReply r;
                // IP to test ping
                string s = "###";

                try
                {
                    r = pinger.Send(s);

                }
                catch (Exception b)
                {
                    MessageBox.Show(b.ToString());
                }
            }
        }
    }

    private void backgroundWorker1_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
    {
        MessageBox.Show("Show me something");

        if(e.Cancelled == true)
        {
            statusLbl1.Text = "Cancelled";
        } else if(e.Error != null)
        {
            statusLbl1.Text = "Error: "   e.Error.Message;
        } else
        {
            statusLbl1.Text = "YEEEEEEEET";
        }
    }

...

uj5u.com熱心網友回復：

您需要將backgroundWorker1_RunWorkerCompleted事件處理程式附加到RunWorkerCompleted事件。C# 編譯器不會根據命名約定將處理程式掛鉤到事件。你必須明確地做到這一點。

public Form1()
{
    InitializeComponent();
    backgroundWorker1.WorkerReportsProgress = true;
    backgroundWorker1.WorkerSupportsCancellation = true;
    backgroundWorker1.DoWork  = backgroundWorker1_DoWork;
    backgroundWorker1.RunWorkerCompleted  = backgroundWorker1_RunWorkerCompleted;
}

uj5u.com熱心網友回復：

如果要保持無限回圈，則必須在 backgroundWorker1_DoWork 方法中進行回圈。像這樣的東西

private void backgroundWorker1_DoWork(object sender, DoWorkEventArgs e)
{
    BackgroundWorker worker = (BackgroundWorker) sender;
    while (!worker.CancellationPending)
    {
        //Do your stuff here
        for(int i = 0; i <= count; i  )
        {
            MessageBox.Show("something is happening");
            // Create ping object
            Ping pinger = new Ping();
            PingReply r;
            // IP to test ping
            string s = "###";

            try
            {
                r = pinger.Send(s);

            }
            catch (Exception b)
            {
                MessageBox.Show(b.ToString());
            }
        }
    }        
 }

此外，從后臺執行緒顯示訊息框也不是一個好主意，將其登錄到控制臺或任何檔案中。

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