#include "mainwindow.h"
#include "ui_mainwindow.h"
#include <windows.h>
#include <QThread>

char readBuf[1024]={0};
Ui::MainWindow *_ui=NULL;

class myThread: public QThread{
public:
    HANDLE obj;
    DWORD written;
    OVERLAPPED lapped;
    myThread(){
        obj=CreateFile(L"COM2",GENERIC_READ|GENERIC_WRITE,0,NULL,OPEN_EXISTING
                       ,FILE_FLAG_OVERLAPPED//尝试用异步方式
                       ,NULL);
        SetupComm(obj,1024,1024);
        DCB dcb;
        dcb.BaudRate=9600;
        dcb.ByteSize=8;
        dcb.Parity=NOPARITY;
        dcb.StopBits=1;
        SetCommState(obj,&dcb);
        lapped.hEvent=CreateEvent(NULL,TRUE,FALSE,NULL);//加了这行以测试
        WriteFile(obj,"hello",5,&written,&lapped);
    }
private:
    virtual void run() override{
        while(TRUE){
            //编译通过，但是导致电脑卡死,究其原因是循环导致
            if(!ReadFile(obj,readBuf,1024,&written,&lapped)){
                WaitCommEvent(obj,&written,&lapped);
            }else{
                _ui->textBrowser->insertPlainText(readBuf);
            }
        }
    }
};

MainWindow::MainWindow(QWidget *parent):QMainWindow(parent),ui(new Ui::MainWindow)
{
    ui->setupUi(this);
    _ui=ui;
    myThread *test=new myThread();
    test->start();
    test->quit();
}

MainWindow::~MainWindow()
{
    delete ui;
}