调用USB的摄像头扫描二维码

【核心代码】

namespace Camera
{
    public partial class MainForm : Form
    {
        /// <summary>
        /// 摄像头对象
        /// </summary>
        private Capture cam;

        /// <summary>
        /// 定时器对象
        /// </summary>
        System.Timers.Timer  timer = null;

        /// <summary>
        /// 扫描时间
        /// </summary>
        private int scanTime = 250;

        /// <summary>
        /// 摄像头的状态
        /// </summary>
        private bool videoState = false;

        private IContainer componentss;

        /// <summary>
        /// 构造函数
        /// </summary>
        public MainForm()
        {
            Control.CheckForIllegalCrossThreadCalls = false;
            InitializeComponent();
            pictureBox1.Visible = false;
            btnStop.Enabled = false;
        }

        /// <summary>
        ///
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnStart_Click(object sender, EventArgs e)
        {
            btnStart.Enabled = false;
            btnStop.Enabled = true;
            StartCam();
            if(timer != null && timer.Enabled)
            {
                timer.Stop();
                timer.Dispose();
            }
            timer = new System.Timers.Timer(scanTime);
            timer.Start();
            timer.Elapsed = new System.Timers.ElapsedEventHandler(_timer_Elapsed);
        }

        /// <summary>
        ///
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void _timer_Elapsed(object sender ,System.Timers.ElapsedEventArgs e)
        {
            try
            {
                string result = SnapShot();
                if(string.IsNullOrEmpty(result))
                {
                    if(pictureBox1.Image == null)
                    {
                        return;
                    }
                    else
                    {
                        try
                        {
                            result = RQDecode(new Bitmap(pictureBox1.Image));
                        }
                        catch(Exception ee)
                        {
                            MessageBox.Show(ee.Message);
                        }

                        if(result != null && string.IsNullOrEmpty(result))
                        {
                            this.textBoxMsg1.Text = result;
                            MessageBox.Show(result, "OK", MessageBoxButtons.OKCancel);
                            CreateQRCode(result);
                        }
                        else
                        {
                            MessageBox.Show("未扫描到二维码");
                        }
                    }
                }
            }
            catch(Exception ex)
            {
                MessageBox.Show(ex.Message);
            }

        }

        /// <summary>
        ///
        /// </summary>
        private void StartCam()
        {
            const int VIDEODEVICE = 0;
            const int VIDEOWIDTH = 640;
            const int VIDEOHEIGHT = 480;
            const int VIDEOBITSPERPIXEL = 32;

            cam = new Capture(VIDEODEVICE, VIDEOWIDTH, VIDEOHEIGHT, VIDEOBITSPERPIXEL,pictureBox2);
            videoState = true;
        }

        /// <summary>
        ///
        /// </summary>
        private void StopCam()
        {
            cam.Dispose();

        }

        /// <summary>
        /// 生成二维码，并显示到界面上
        /// </summary>
        /// <param name="content"></param>
        private void CreateQRCode(string content)
        {
            EncodingOptions options = null;
            BarcodeWriter writer = null;
            options = new QrCodeEncodingOptions
            {
                DisableECI = true,
                CharacterSet = "UTF-8",
                Width = pictureBox3.Width,
                Height = pictureBox3.Height
            };

            writer = new BarcodeWriter();
            writer.Format = BarcodeFormat.QR_CODE;
            writer.Options = options;

            Bitmap bitmap = writer.Write(content);
            pictureBox3.Image = bitmap;
        }

        /// <summary>
        /// 截图
        /// </summary>
        /// <returns></returns>
        private string SnapShot()
        {
            Cursor current = Cursors.WaitCursor;
            if(m_ip != IntPtr.Zero)
            {
                Marshal.FreeCoTaskMem(m_ip);
                m_ip = IntPtr.Zero;
            }

            //m_ip = cam.Click();

            string result = string.Empty;

            return result;
        }

        /// <summary>
        ///
        /// </summary>
        /// <param name="img"></param>
        /// <returns></returns>
        private string RQDecode(Bitmap img)
        {
            string errText = string.Empty;

            return errText;
        }

        /// <summary>
        ///
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void btnStop_Click(object sender, EventArgs e)
        {
            btnStart.Enabled = true;
            btnStop.Enabled = false;
            this.textBoxMsg1.Text = string.Empty;
            //停止摄像头
            StopCam();
            //定时器停止工作
            timer.Stop();
            timer.Dispose();
        }
    }
}