Question

阅读有关C＃BackgroundWorker的大多数（所有？）已回答的问题，但似乎没有一个适用于这种情况。如果我错过了一个，请指出我的方向！

无论如何，我遇到麻烦让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发送ping和报告。这很好但但只有在ping完成后才会给用户带来结果 - 因此需要后台进程。我对C＃不太熟悉，并且不熟悉BackgroundWorker的细节。但是，在这里找到了Microsoft的有用演练：http://msdn.microsoft.com/en-us/library/ywkkz4s1.aspx

我现在正尝试将相同的进程应用于System.Net.NetworkInformation对象而不是System.IO.StreamReader对象。我认为我非常接近（阅读：我可以让应用程序构建和运行）但我在运行时始终遇到错误（见下文）。

这是他们的示例应用程序的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'类中的相关方法

   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，我收到此错误：

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（var名称不同，但你明白了）：

void Bw01DoWork(object sender, DoWorkEventArgs e)
    {
        System.ComponentModel.BackgroundWorker worker;
        worker = (System.ComponentModel.BackgroundWorker)sender;
        PTResults PR = (PTResults)e.Argument;
        PR.SendPings(worker, e);  // Line 152
    }

PTResults.cs课程的相关部分：

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组件不能以与System.IO.StreamReader相同的方式调用。想法？

我怀疑它有所不同，但FWIW我在Windows 8.1系统上使用SharpDevelop进行编码。

Answer 1

看一下Ping SendAsync，您可以消除大部分代码 - 只需调用PingAsync，并处理结果，确保将其分派到UI线程，然后重新排队另一个调用。

http://msdn.microsoft.com/en-us/library/ms144961(v=vs.110).aspx

获取C＃BackgroundWorker进程以调用Pings

1 个答案: