internal class ScreenRecordHelper

    {

        #region Fields

        private const int DEFAULT_FRAME_RATE = ;

        private int screenWidth;

        private int screenHight;

        private int bitRate;

        private int frameRate;

        internal bool isRecording;

        private int framesCount;

        private string fileName;

        private Stopwatch stopWatch;

        private Rectangle screenArea;

        private VideoFileWriter videoWriter;

        private ScreenCaptureStream videoStreamer;

        private FolderBrowserDialog folderBrowser;

        private VideoCodec videoCodec;

        #endregion

        public ScreenRecordHelper()

        {

            screenWidth = SystemInformation.VirtualScreen.Width;//Screen.PrimaryScreen.Bounds.Width;

            screenHight = SystemInformation.VirtualScreen.Height; // Screen.PrimaryScreen.Bounds.Height;不论注释的或没注释的发现在win10系统上是不能全屏录制的，
　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　只能部分，win8上没试过，由于我装的是win10系统，没有win7，就先这样写了，至于win10系统有自己的
　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　一套录制方法，还挺牛逼，我们可以使用win+G键来开始，还可以自己来创建录制软件（只适用于win8.x
　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　及其以上）,msdn提供了文章：
　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　https://msdn.microsoft.com/zh-cn/library/windows/apps/xaml/dn642093.aspx

            frameRate = DEFAULT_FRAME_RATE;

            isRecording = false;

            framesCount = default(int);

            stopWatch = new Stopwatch();

            screenArea = Rectangle.Empty;

            videoWriter = new VideoFileWriter();

            folderBrowser = new FolderBrowserDialog();

            videoCodec = (VideoCodec)Enum.Parse(typeof(VideoCodec), ScreenRecord.codec);

            bitRate = ScreenRecord.bitRate;

        }

        /// <summary>

        /// 开始录屏

        /// </summary>

        internal void StartRecording()

        {

            try

            {

                InitializeRecordingParameters();

                videoStreamer = new ScreenCaptureStream(screenArea);

                videoStreamer.NewFrame += new NewFrameEventHandler(VideoStreamer_NewFrame);

                videoStreamer.Start();

                stopWatch.Start();

            }

            catch (Exception ex)

            {

                throw ex;

            }

        }

        internal void StopRecord()

        {

            isRecording = false;

        }

        private void VideoStreamer_NewFrame(object sender, NewFrameEventArgs eventArgs)

        {

            if (isRecording)

            {

                framesCount++;

                videoWriter.WriteVideoFrame(eventArgs.Frame);

            }

            else

            {

                stopWatch.Reset();

                videoStreamer.Stop();

                videoWriter.Close();

                videoWriter.Dispose();

            }

        }

        private void InitializeRecordingParameters()

        {

            if (!isRecording)

            {

                isRecording = true;

                SetScreenArea();

                FileName = string.Format(@"{0}{1}-{2}.avi", "ScreenDraw", "bySTAR", new Random().Next() + DateTime.Now.ToString("yyyy-MM-dd_HH_mm"));

                videoWriter.Open(FileName, screenWidth, screenHight, frameRate, videoCodec, bitRate);

            }

        }

        private string FileName

        {

            get { return this.fileName; }

            set

            {

                if (string.IsNullOrEmpty(value))

                {

                    throw new ArgumentNullException

                        ("fileName", "File name can not be empty or null");

                }

                this.fileName = value;

            }

        }

        private void SetScreenArea()

        {

            foreach (Screen screen in Screen.AllScreens)

            {

                this.screenArea = Rectangle.Union(this.screenArea, screen.Bounds);

            }

            if (this.screenArea == Rectangle.Empty)

            {

                throw new InvalidOperationException("Screan area can not be set");

            }

        }

    }

internal static string savePath = Directory.GetCurrentDirectory();

internal static string codec = "MSMPEG4v2";

internal static int bitRate = ;