让C#BackgroundWorker进程调用ping

通读关于C#BackgroundWorker的大部分（全部？）回答问题，但似乎没有一个适用于这种情况。如果我错过了一个，请告诉我那个方向

无论如何，我很难让Ping进程作为后台进程运行。我做了一个简单的表单应用程序来发送ping并返回报告。这很好，但它只会在ping完成后向用户显示结果——因此需要一个后台进程。我对C#有点陌生，对幕后工作人员的细节不太熟悉。但是，您在此处找到了Microsoft提供的有用演练：

我现在尝试将相同的过程应用于System.Net.NetworkInformation对象，而不是System.IO.StreamReader对象。我认为我真的很接近（阅读：我可以让应用程序构建和运行），但我总是在运行时出错（见下文）

这是他们示例应用程序的Microsoft代码。它就像一个冠军：

MainForm.cs中调用演练中引用的Words.cs类的方法

void backgroundWorker1DoWork(object sender, DoWorkEventArgs e)
    {
        System.ComponentModel.BackgroundWorker worker;
        worker = (System.ComponentModel.BackgroundWorker)sender;
        Words WC = (Words)e.Argument;
        WC.CountWords(worker, e);
    }

“Words.cs”课程中的相关方法

   public void CountWords(
        System.ComponentModel.BackgroundWorker worker,
        System.ComponentModel.DoWorkEventArgs e)
    {
        // Initialize the variables.
        CurrentState state = new CurrentState();
        string line = "";
        int elapsedTime = 20;
        DateTime lastReportDateTime = DateTime.Now;

        if (CompareString == null ||
            CompareString == System.String.Empty)
        {
            throw new Exception("CompareString not specified.");
        }
        // Open a new stream.        
        using (System.IO.StreamReader myStream = new System.IO.StreamReader(SourceFile))
        {
            // Process lines while there are lines remaining in the file. 
            while (!myStream.EndOfStream)
            {
                if (worker.CancellationPending)
                {
                    e.Cancel = true;
                    break;
                }
                else
                {
                    line = myStream.ReadLine();
                    WordCount += CountInString(line, CompareString);
                    LinesCounted += 1;

                    // Raise an event so the form can monitor progress. 
                    int compare = DateTime.Compare(
                        DateTime.Now, lastReportDateTime.AddMilliseconds(elapsedTime));
                    if (compare > 0)
                    {
                        state.LinesCounted = LinesCounted;
                        state.WordsMatched = WordCount;
                        worker.ReportProgress(0, state);
                        lastReportDateTime = DateTime.Now;
                    }
                }
                // Uncomment for testing. 
                System.Threading.Thread.Sleep(5);
            }

            // Report the final count values.
            state.LinesCounted = LinesCounted;
            state.WordsMatched = WordCount;
            worker.ReportProgress(0, state);
        }
    }

当我尝试类似的过程（发送Ping而不是读取文件）时，会出现以下错误：

Error: Object reference not set to an instance of an object.
Details: System.Collections.ListDictionaryInternal //This is defined in the MyApp namespace as: using System.Collections
Source: MyApp
StackTrack:    at MyApp.MainForm.Bw01DoWork(Object sender, DoWorkEventArgs e) in
[path]\MainForm.cs:line 152
   at System.ComponentModel.BackgroundWorker.OnDoWork(DoWorkEventArgs e)
   at System.ComponentModel.BackgroundWorker.WorkerThreadStart(Object argument)
Target: Void Bw01DoWork(System.Object, System.ComponentModel.DoWorkEventArgs)

这是我的方法。错误中引用的第152行是MainForm.cs中最后一个方法的最后一行（变量名称不同，但您知道了）：

以及PTResults.cs类的相关部分：

using (Ping newPing = new Ping())
        {
            PingReply reply = newPing.Send([Target Site],[Timeout]);
            if(reply.Status == IPStatus.Success)
            {
                state.PingOK = true;
            }
            else if(reply.Status == IPStatus.TimedOut)
            {
                state.PingOK = false;
                state.PingUpdateState = " Timed Out";                   
            }
            else if(reply.Status != IPStatus.Success)
            {
                state.PingOK = false;
                state.PingUpdateState = " FAILED";                          
            }
            else
            {
                state.PingOK = false;
                state.PingUpdateState = " UNKNOWN";                     
            }
            worker.ReportProgress(0, state.PingOK);
        }

我认为System.Net.NetworkInformation.Ping组件不能像System.IO.StreamReader那样调用。想法

---

我怀疑这会有什么不同，但FWIW我正在Windows 8.1系统上使用SharpDevelop进行编码。

看看Ping SendAsync，您可能能够消除大部分代码-只需调用PingAsync，并处理结果，确保将其分派到UI线程，然后重新排队等待另一个调用

---

我的回答有帮助吗？还没有。我正在修补PingAsync。然而，我仍然不知道为什么我的代码写得不好（因为IO流工作得很好）。甚至可以用这种方式使用Ping吗，或者PingAsync是这里唯一的实际选项吗？

using (Ping newPing = new Ping())
        {
            PingReply reply = newPing.Send([Target Site],[Timeout]);
            if(reply.Status == IPStatus.Success)
            {
                state.PingOK = true;
            }
            else if(reply.Status == IPStatus.TimedOut)
            {
                state.PingOK = false;
                state.PingUpdateState = " Timed Out";                   
            }
            else if(reply.Status != IPStatus.Success)
            {
                state.PingOK = false;
                state.PingUpdateState = " FAILED";                          
            }
            else
            {
                state.PingOK = false;
                state.PingUpdateState = " UNKNOWN";                     
            }
            worker.ReportProgress(0, state.PingOK);
        }