csharp-thread

Task and Thread

Task的背后的实现也是使用了线程池线程，但它的性能优于ThreadPoll,因为它使用的不是线程池的全局队列，而是使用的本地队列，使线程之间的资源竞争减少。同时Task提供了丰富的API来管理线程、控制。但是相对前面的两种耗内存，Task依赖于CPU对于多核的CPU性能远超前两者，单核的CPU三者的性能没什么差别。

Task.Run 和 Task.Factory.StartNew 里面有异常的时候都是不会抛出来的，需要在内部捕获

WaitAll is a blocking call
WhenAll - not - code will continue executing

Task

private Task taskPythonPlugin;

taskPythonPlugin = new Task(() =>
        {
            Console.WriteLine("task start");
            task_pyton_plugin();
        });

taskPythonPlugin.Start();

public void task_pyton_plugin()
{
}

var testTask = new Task(() =>
        {
            Console.WriteLine("task start");
            System.Threading.Thread.Sleep(2000);
        });
testTask.Start();
testTask.Wait();

Task.Run 和 Task.Factory.StartNew

异步串联多个任务

class Program
{
        /*  coder:释迦苦僧    */
        static void Main(string[] args)
        {
                /*创建任务t1*/
                Task t1 = Task.Factory.StartNew(() =>
                {
                Console.WriteLine("执行 t1 任务");
                SpinWait.SpinUntil(() =>
                {
                        return false;
                }, 2000);

                });
                /*创建任务t2   t2任务的执行 依赖与t1任务的执行完成*/
                Task t2 = t1.ContinueWith((t) =>
                {
                Console.WriteLine("执行 t2 任务"); 
                SpinWait.SpinUntil(() =>
                {
                        return false;
                }, 2000);

                });    
                /*创建任务t3   t3任务的执行 依赖与t2任务的执行完成*/
                Task t3 = t2.ContinueWith((t) =>
                {
                Console.WriteLine("执行 t3 任务");
                });
                Console.ReadLine();
        }
}

thread

等待延时

System.Threading.Thread.Sleep(numberOfMilliseconds);

同步

// true signaled; false  non-signaled
AutoResetEvent autoResetEvent = new AutoResetEvent(false);

// true signaled; false  non-signaled
ManualResetEvent manualResetEventPlcHeartbeat = new ManualResetEvent(true);

autoResetEvent.WaitOne();

autoResetEvent.Set();
autoResetEvent.Reset();

lock statment

msdn

// 访问PLC同步锁
private readonly object LockAccess = new object();
lock (LockAccess)
{
    ...
}

kill

// name without .exe
foreach (var process in Process.GetProcessesByName("whatever"))
{
    process.Kill();
}

获取指定进程路径

// name without .exe
foreach (var process in Process.GetProcessesByName("nisedit"))
{
        // 获取路径
        spc_path = new FileInfo(process.MainModule.FileName).Directory.FullName;
        // 完整路径包括文件名
        var ss = process.MainModule.FileName;
        // 获取路径，不包括文件名
        ss = new FileInfo(spc_path).Directory.FullName;
        process.Kill();
}

进程通讯

REST, gRPC

调用外部进程

try
{
        // call python plugin
        Process p = new Process();
        p.StartInfo = new ProcessStartInfo(App.appPath + @"\plugin\python_plugin.exe");
        p.StartInfo.Arguments = App.appPath + @"\plugin\run.py";
        p.StartInfo.WorkingDirectory = App.appPath + @"\plugin\";
        p.StartInfo.CreateNoWindow = true;
        p.StartInfo.UseShellExecute = false;
        p.Start();
}catch(Exception ex)
{
        Log.Error("load python plugin failed. " + ex.Message);
}

调用 cmd 执行命令

try
{
        System.Diagnostics.Process process = new System.Diagnostics.Process();
        System.Diagnostics.ProcessStartInfo startInfo = new System.Diagnostics.ProcessStartInfo();
        startInfo.WindowStyle = System.Diagnostics.ProcessWindowStyle.Hidden;
        startInfo.FileName = "cmd.exe";
        startInfo.Arguments = $"/C {storeExcelPath}";
        startInfo.Verb = "runas";
        startInfo.CreateNoWindow = true;
        // 想使用管理员权限，这里必须是 true
        startInfo.UseShellExecute = true;
        process.StartInfo = startInfo;
        process.Start();
        process.WaitForExit();
        process.Close();

        tb_status.Text = "状态：正在打开Excel文档";
        statusTimer.Start();
}
catch (Exception ex)
{
        Log.Error("load python plugin failed. " + ex.Message);
        MessageBox.Show($"打开文档失败 msg={ex.Message}");
}

调用外部进程获取返回值

// Synchronous example
static void runCommand()
{
    Process process = new Process();
    process.StartInfo.FileName = "cmd.exe";
    process.StartInfo.Arguments = "/c DIR"; // Note the /c command (*)
    process.StartInfo.UseShellExecute = false;
    process.StartInfo.RedirectStandardOutput = true;
    process.StartInfo.RedirectStandardError = true;
    process.Start();
    //* Read the output (or the error)
    string output = process.StandardOutput.ReadToEnd();
    Console.WriteLine(output);
    string err = process.StandardError.ReadToEnd();
    Console.WriteLine(err);
    process.WaitForExit();
}

// (*) For some commands (here StartInfo.Arguments) you must add the /c directive, otherwise the process freezes in the WaitForExit().

// Asynchronous example
static void runCommand() 
{
    //* Create your Process
    Process process = new Process();
    process.StartInfo.FileName = "cmd.exe";
    process.StartInfo.Arguments = "/c DIR";
    process.StartInfo.UseShellExecute = false;
    process.StartInfo.RedirectStandardOutput = true;
    process.StartInfo.RedirectStandardError = true;
    //* Set your output and error (asynchronous) handlers
    process.OutputDataReceived += new DataReceivedEventHandler(OutputHandler);
    process.ErrorDataReceived += new DataReceivedEventHandler(OutputHandler);
    //* Start process and handlers
    process.Start();
    process.BeginOutputReadLine();
    process.BeginErrorReadLine();
    process.WaitForExit();
}

static void OutputHandler(object sendingProcess, DataReceivedEventArgs outLine) 
{
    //* Do your stuff with the output (write to console/log/StringBuilder)
    Console.WriteLine(outLine.Data);
}