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WPF演示，抓取flv视频

我们来做个WPF的windows程序，想要抓取FLV视频。

1.新建一个wpf project

2.编辑windows1.xaml

这里有一个textbox，两个textblock，一个gif动画，一个进度条

3.wpf下GIF动画的显示

找了一个GifImageLib.dll

编辑xaml

  <my:GifImage Margin="27,92,0,0" Name="imageLoad" RenderTransformOrigin="0.5,0.5" Source="Images\loader.gif" Stretch="Uniform" xmlns:my="clr-namespace:GifImageLib;assembly=GifImageLib" HorizontalAlignment="Left" Width="16" Visibility="Hidden" Height="18" VerticalAlignment="Top">
            <my:GifImage.RenderTransform>
                <TransformGroup>
                    <ScaleTransform ScaleX="1" ScaleY="1" />
                    <SkewTransform AngleX="0" AngleY="0" />
                    <RotateTransform Angle="0" />
                    <TranslateTransform X="0" Y="0" />
                </TransformGroup>
            </my:GifImage.RenderTransform>
        </my:GifImage>

4.进度条的显示

说道进度条，一定是用多线程了，试验了第一次

//第一次尝试,gif不能动，可以显示
imageLoad.Visibility = Visibility.Visible;

new Thread(() =>
{
    Dispatcher.BeginInvoke(DispatcherPriority.Normal, new Action(() =>
    {
        Thread.Sleep(5000);
        imageLoad.Visibility = Visibility.Hidden;
        tbWait.Visibility = Visibility.Hidden; 

    }));
}).Start();

用的是Dispatcher.BeginInvoke()方法，结果是gif能显示，但不能动，失败

查了msdn，换了种方法，简单明了

  _backgroundWorker = new BackgroundWorker();
            _backgroundWorker.DoWork+=new DoWorkEventHandler(DoWork);
            _backgroundWorker.RunWorkerCompleted += new RunWorkerCompletedEventHandler(FinsihWork);
            BeforeWork();
            _backgroundWorker.RunWorkerAsync();
            _backgroundWorker.Dispose();

不错，就是BackgroundWorker，注意这要引用using System.ComponentModel;

gif能动了。

        private void DoWork(object sender, DoWorkEventArgs e)
        {
            //模拟进度条
            for (int i = 0; i < 10; i ++)
            {
                Dispatcher.BeginInvoke(DispatcherPriority.Normal, new Action(() =>
                {
                    WorkProgress.Value = i*10;
                }));
                Thread.Sleep(100);
            }
            try
            {
                if(strUrl!=string.Empty)
                    parseUrl(strUrl);
            }
            catch
            {
                    flvUrl="error";
            }
        }
        private void BeforeWork()
        {
            imageLoad.Visibility = Visibility.Visible;
            WorkProgress.Visibility = Visibility.Visible;
            WorkProgress.Maximum = 100;
            WorkProgress.Minimum = 0;
            WorkProgress.Value = 0;
            btnGet.IsEnabled = false;
            strUrl = textBox1.Text;
        }

        private void FinsihWork(object sender,RunWorkerCompletedEventArgs e)
        {
            WorkProgress.Visibility = Visibility.Hidden;
            imageLoad.Visibility = Visibility.Hidden;
            btnGet.IsEnabled = true;
            if (flvUrl != "error")
                tbResult.Text = flvUrl;
        }

5.抓取flv的算法

这里我们采用httpwatch插件，又免费的 HttpWatch Basic Edition 下载

添加引用

在com里找到httpwatch，ok

算法如下：

 private bool parseUrl(string URL)
        {
            bool bResult = UrlExistsUsingHttpWebRequest(URL);
            if (bResult)
            {
                HttpWatch.ControllerClass ct = new HttpWatch.ControllerClass();
                HttpWatch.Plugin plugin = ct.IE.New();
                plugin.Log.EnableFilter(false);
                plugin.Record();
                plugin.GotoURL(URL);
                ct.Wait(plugin, -1);
                foreach (HttpWatch.Entry entry in plugin.Log.Entries)
                {
                    if (entry.IsRedirect)
                        parseUrl(entry.URL);
                    else
                    {
                        if (entry.URL.ToLower().Contains(".flv"))
                        {
                            flvUrl = entry.URL;
                            Dispatcher.BeginInvoke(DispatcherPriority.Normal,new Action(()=>{
                                tbResult.Text = flvUrl;
                            }));
                        }
                    }
                }
                plugin.Stop();
                plugin.CloseBrowser();
            }
            return bResult;
        }

        private bool UrlExistsUsingHttpWebRequest(string url)
        {
            try
            {
                System.Net.WebRequest.Create(url);
                return true;
            }
            catch
            {
                return false;
            }
        }

6.显示得到文件的路径，并点击下载

     private void tbResult_MouseDown(object sender, MouseButtonEventArgs e)
        {
            if (flvUrl != "error") 
                System.Diagnostics.Process.Start(flvUrl);
        }