Question

我是C＃的新手，并实现了一个代码，其中我有两个按钮，一个用作数据采集的开始并将其存储在csv文件中，另一个按钮用于停止它。

所有这些的代码如下：

//按钮启动DAQ

    private void stdaq_Click(object sender, EventArgs e)
    {
        stopped = false;

       process();


    }

//用于停止DAQ的按钮

    private void spdaq_Click(object sender, EventArgs e)
    {

        stopped = true;
    }

//处理功能

private process()
    {
            int iAvail = 0;
            int iRead = 0;

            string filename = @textBox3.Text;// taking csv file name from user
       // jit:

            //a function calculating the total number of values and storing it in iAvail



            int[] iRawData = new Int32[iAvail];
            double[] dScaledData = new Double[iAvail];


            //a function transferring the data from buffer and storing it in dscaledData array

            List<double> data = new List<double>();
            for (int i = 0; i < iAvail; i++)
            {
                data.Add(dScaledData[i]);
            }

            Task myFirstTask = Task.Factory.StartNew(()
                                     => 
                                     {
                                         while (stopped == false)
                                         {
                                             Write(data.ToArray(), filename);
                                            // goto jit;
                                         }
                                     });


    }

// csv creater and data writer

public static void Write(double[] data, string outputPath)
    {

        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < data.GetLength(0); i++)
        {
            if (stopped) break;
            sb.AppendLine(string.Join(",", data[i]));
        }

        if (File.Exists(outputPath))
        {
            File.AppendAllText(outputPath, sb.ToString());
        }
        else
        {
            File.WriteAllText(outputPath, sb.ToString());
        }
    }

这就是我正在实现的，这段代码的问题在于，当数据首次传输并写入文件时，无论新数据如何，我都会一次又一次地写入相同的数据，并尝试实现Goto语句（可以在注释中看到）但它给出错误 - “控件不能离开匿名方法或lambda表达式的主体”，如果我不使用While循环，则根本不写入数据。

所以我想调用我的过程函数并在按下开始按钮时将数据传输到csv，每次都获取新数据并将其写入csv，或者可以说从它的起点再次调用过程方法单击停止按钮停止它，但我无法做到这一点，无论各种尝试使用不同的循环和一些线程功能。

请帮助解决这个问题。

Answer 1

假设您只需要Write一次，则应将其删除或将其从while更改为if：

while (stopped == false)

循环将导致Write被无限调用，直到stopped变为true。

此外，如果Write为return，您可能希望将break更改为stopped而不是true，这样您就不会写如果你应该停下来的话：

        if (stopped) break;

到

        if (stopped) return;

如果你想再次生成data并且确实想要永远循环，只需将该代码移动到循环中：

Task myFirstTask = Task.Factory.StartNew(()
     => 
     {
         while (stopped == false)
         {
             List<double> data = new List<double>();
             // TODO: Generate data here - move all relevant code here

             Write(data.ToArray(), filename);
         }
     });

Answer 2

我认为这是 BackgroundWorker 的工作。

此代码将启动您：

public partial class Form1 : Form
{
    int loopCounter = 0;        // variable just used for illustration      
    private static BackgroundWorker bw = new BackgroundWorker();        // The worker object

    // This function does your task
    public void doSomeStuff(object sender, DoWorkEventArgs e)
    {
        for (int i = 0; i < 1000; i++)
        {
            loopCounter = i;    // Pass the loop count to this variable just to report later how far the loop was when the worker got cancelled.
            Thread.Sleep(100);  // Slow down the loop

            // During your loop check if the user wants to cancel
            if (bw.CancellationPending)
            {
                e.Cancel = true;
                return; // quit loop
            }
        }
    }

    // This button starts your task when pressed
    private void button1_Click(object sender, EventArgs e)
    {
        bw.WorkerSupportsCancellation = true;   // Set the worker to support cancellation
        bw.DoWork += doSomeStuff;               // initialize the event
        if (!bw.IsBusy)                         // Only proceed to start the worker if it is not already running.
        {
            bw.RunWorkerAsync();                // Start the worker
        }
    }

    // This button stops your task when pressed
    private void button2_Click(object sender, EventArgs e)
    {
        // Request cancellation
        bw.CancelAsync();

        textBox1.Text = "The bw was cancelled when 'loopCounter' was at: " + loopCounter.ToString();

    }

}

我的代码需要某种循环或跳转语句

2 个答案: