我对混合事件和线程知之甚少。场景是在 PC 上运行 C# 程序，在 PLC 上运行 Twincat。我们需要访问 C# 程序中的 PLC 变量（已经在没有后台工作线程的情况下完成并且工作正常。），现在我们需要将这些处理移动到一个线程（最好是后台工作线程）。这是不工作的代码。（表单包含一个 START 按钮，它将启动 BGWorker，一个 STOP 按钮将取消 BGWorker，以及一个 UPDATE 按钮，它将值从 PLC 更新到文本框。），但现在 tcClient_OnNotification没有被调用！请指出我遗漏的地方，任何帮助将不胜感激。
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Threading; // not added by default
using System.IO; // not added by default
using TwinCAT.Ads; // not added by default
namespace BGworker
{
public partial class Form1 : Form
{
private BackgroundWorker bw = new BackgroundWorker();
private TcAdsClient tcClient; // C# program is the client.
private AdsStream dataStream; // Data transfered through System IOStream
private BinaryReader binReader; // We are now reading value from PLC
private int Hintval; // Handle for integer value
public static bool looping = true;
public static string receivedtext = "";
public Form1()
{
InitializeComponent();
bw.WorkerReportsProgress = true;
bw.WorkerSupportsCancellation = true;
bw.DoWork += new DoWorkEventHandler(bw_DoWork);
bw.ProgressChanged += new ProgressChangedEventHandler(bw_ProgressChanged);
bw.RunWorkerCompleted += new RunWorkerCompletedEventHandler(bw_RunWorkerCompleted);
}
private void Form1_Load(object sender, EventArgs e)
{
}
private void Startbutton_Click(object sender, EventArgs e)
{
if (bw.IsBusy != true)
{
bw.RunWorkerAsync();
}
}
private void Stopbutton_Click(object sender, EventArgs e)
{
if (bw.WorkerSupportsCancellation == true)
{
bw.CancelAsync();
}
}
public void bw_DoWork(object sender, DoWorkEventArgs e)
{
BackgroundWorker worker = sender as BackgroundWorker;
dataStream = new AdsStream(1 * 2); // Single value will be read
binReader = new BinaryReader(dataStream, Encoding.ASCII);
tcClient = new TcAdsClient();
tcClient.Connect(801);
//Hintval = tcClient.CreateVariableHandle(".GOUTINT");
Hintval = tcClient.AddDeviceNotification(".GOUTINT", dataStream, 0, 2, AdsTransMode.OnChange, 100, 0, null);
tcClient.AdsNotification += new AdsNotificationEventHandler(tcClient_OnNotification);
while (true)
{
if ((worker.CancellationPending == true))
{
e.Cancel = true;
break;
}
else
{
System.Threading.Thread.Sleep(100);
//worker.ReportProgress((5* 10));
}
}
tcClient.Dispose();
}
public void tcClient_OnNotification(object sender, AdsNotificationEventArgs e)
{
try
{
// Setting the position of e.DataStream to the position of the current required value
e.DataStream.Position = e.Offset;
// Determining which variable has changed
if (e.NotificationHandle == Hintval)
{
receivedtext = binReader.ReadInt16().ToString();
}
}
catch (Exception ex)
{
MessageBox.Show(ex.Message);
}
}
private void bw_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
{
if ((e.Cancelled == true))
{
this.tbProgress.Text = "Canceled!";
}
else if (!(e.Error == null))
{
this.tbProgress.Text = ("Error: " + e.Error.Message);
}
else
{
this.tbProgress.Text = "Done!";
}
}
private void bw_ProgressChanged(object sender, ProgressChangedEventArgs e)
{
this.tbProgress.Text = (e.ProgressPercentage.ToString() + "%");
}
private void buttonUpdate_Click(object sender, EventArgs e)
{
this.tbProgress.Text = receivedtext;
}
}
}
提前致谢。阿比拉什。