C# 根据URL返回HTML_根据URL获取图片信息/缩略图

/// <summary>
/// 根据URL 返回HTML
/// </summary>
private List<string> GetHtmlByUrl(string Url)
{
WebClient client = new WebClient();
byte[] page = client.DownloadData(Url);
string content = System.Text.Encoding.UTF8.GetString(page);
List<string> _list = GetImgUrlByHtmlText(content);
return _list;
}

/---------------------根据URL--获取图片信息--------------/

//后缀名
string _suffix = _imgurls[i].Substring(_imgurls[i].Length - );
//图片文件名
string _imageInputTitle = "云鼎宝贝" + DateTime.Now.ToString("yyyyMMddhhmmss" + i) + _suffix;
System.Net.HttpWebRequest webRequest = (System.Net.HttpWebRequest)System.Net.WebRequest.Create(_imgurls[i]);
webRequest.Method = "GET";
System.Net.HttpWebResponse webResponse = (System.Net.HttpWebResponse)webRequest.GetResponse();
//获取图片保存到流
System.IO.Stream _stream = webResponse.GetResponseStream();
//保存到图片
System.Drawing.Image _image = System.Drawing.Image.FromStream(_stream);

// int _picwidth = _imgWidth.Length <= 0 ? _image.Width : Convert.ToInt32(_imgWidth);
// int _picheight = _imgHeight.Length <= 0 ? _image.Height : Convert.ToInt32(_imgHeight);

//根据参数形成缩略图
//_image = _image.GetThumbnailImage(_image.Width, _image.Height, null, IntPtr.Zero);

//实例化MemoryStream
System.IO.MemoryStream _ImageMem = new System.IO.MemoryStream();

//实例化图片格式
//ImageFormat _imgFormat = new ImageFormat(new Guid());

//根据图片后缀名判断类型.
// if (_suffix.ToLower().Equals(".jpg")) _imgFormat = ImageFormat.Jpeg;
// if (_suffix.ToLower().Equals(".png")) _imgFormat = ImageFormat.Png;
// if (_suffix.ToLower().Equals(".gif")) _imgFormat = ImageFormat.Gif;

//保存
_image.Save(_ImageMem, _image.RawFormat);
//转换为字节流
byte[] _ImageBytes = _ImageMem.GetBuffer();
//释放资源
_image.Dispose();
//关闭流
_stream.Close();

/------------图片生成缩略图--------------?

#region  生成缩略图
  ///<summary>
  /// 生成缩略图
  /// </summary>
  /// <param name="originalImagePath">源图路径（物理路径）</param>
  /// <param name="thumbnailPath">缩略图路径（物理路径）</param>
  /// <param name="width">缩略图宽度</param>
  /// <param name="height">缩略图高度</param>
  /// <param name="mode">生成缩略图的方式</param>
  public  void MakeThumbnail(string originalImagePath,  string thumbnailPath, int width, int height, string mode out string outthumbnailPath)
  {
   System.Drawing.Image originalImage =System.Drawing.Image.FromFile(originalImagePath);  

   int towidth = width;
   int toheight = height;  

   int x = ;
   int y = ;
   int ow = originalImage.Width;
   int oh = originalImage.Height;
   switch (mode)
   {
    case "HW"://指定高宽缩放（可能变形）
     break;
    case "W"://指定宽，高按比例
     toheight = originalImage.Height * width/originalImage.Width;
     break;
    case "H"://指定高，宽按比例
     towidth = originalImage.Width * height/originalImage.Height;
     break;
    case "Cut"://指定高宽裁减（不变形）
     if((double)originalImage.Width/(double)originalImage.Height > (double)towidth/(double)toheight)
     {
      oh = originalImage.Height;
      ow = originalImage.Height*towidth/toheight;
      y = ;
      x = (originalImage.Width - ow)/;
     }
     else
     {
      ow = originalImage.Width;
      oh = originalImage.Width*height/towidth;
      x = ;
      y = (originalImage.Height - oh)/;
     }
     break;
    default :
     break;
   }      

   //新建一个bmp图片
   System.Drawing.Image bitmap = new System.Drawing.Bitmap(towidth,toheight);
   //新建一个画板
   Graphics g = System.Drawing.Graphics.FromImage(bitmap);
   //设置高质量插值法
   g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
   //设置高质量,低速度呈现平滑程度
   g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
   //清空画布并以透明背景色填充
   g.Clear(Color.Transparent);
   //在指定位置并且按指定大小绘制原图片的指定部分
   g.DrawImage(originalImage, new Rectangle(, , towidth, toheight),
    new Rectangle(x, y, ow,oh),
    GraphicsUnit.Pixel);
   try
   {
    //以jpg格式保存缩略图
    bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
    outthumbnailPath=thumbnailPath;
   }
   catch(System.Exception e)
   {
    throw e;
   }
   finally
   {
    originalImage.Dispose();
    bitmap.Dispose();
    g.Dispose();
   }
  }