GDI+ 发生一般性错误解决办法

错误的代码g对象继续占用 未释放资源 如果路径不一样 没问题 相同路径 获取图片进行

缩略会造成GDI错误

  1 /// <summary>
  2         /// 生成缩略图
  3         /// </summary>
  4         /// <param name="originalImagePath">源图路径（物理路径）</param>
  5         /// <param name="thumbnailPath">缩略图路径（物理路径）</param>
  6         /// <param name="width">缩略图宽度</param>
  7         /// <param name="height">缩略图高度</param>
  8
  9         public void CreateMinImage(string originalImagePath, string thumbnailPath, int width, int height)
 10         {
 11             System.Drawing.Image originalImage = System.Drawing.Image.FromFile(HttpContext.Current.Server.MapPath(originalImagePath));
 12
 13             int towidth = width;
 14             int toheight = height;
 15
 16             int ow = originalImage.Width;
 17             int oh = originalImage.Height;
 18
 19             //新建一个bmp图片
 20             System.Drawing.Image bitmap = new System.Drawing.Bitmap(towidth, toheight);
 21
 22             //新建一个画板
 23             System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap);
 24
 25
 26             //设置高质量插值法
 27             g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
 28
 29             //设置高质量,低速度呈现平滑程度
 30             g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
 31
 32             //清空画布并以透明背景色填充
 33             g.Clear(System.Drawing.Color.Transparent);
 34
 35             //在指定位置并且按指定大小绘制原图片的指定部分
 36             g.DrawImage(originalImage, new System.Drawing.Rectangle(0, 0, towidth, toheight));
 37
 38             try
 39             {
 40                 //以jpg格式保存缩略图
 41                 string FileExt = Path.GetFileNameWithoutExtension(originalImagePath);
 42 //这里报错               bitmap.Save(HttpContext.Current.Server.MapPath(thumbnailPath) + FileExt + ".jpg", System.Drawing.Imaging.ImageFormat.Jpeg);
 43             }
 44             catch (System.Exception e)
 45             {
 46                 throw e;
 47             }
 48             finally
 49             {
 50                 originalImage.Dispose();
 51                 bitmap.Dispose();
 52                 g.Dispose();
 53             }
 54
 55         }
 56
 57 //修改后的代码
 58 public void CreateMinImageAndDel(string originalImagePath, string thumbnailPath, int width, int height)
 59         {
 60             Graphics draw = null;
 61             string FileExt = "";
 62
 63             System.Drawing.Image originalImage = System.Drawing.Image.FromFile(HttpContext.Current.Server.MapPath(originalImagePath));
 64
 65             int towidth = width;
 66             int toheight = height;
 67
 68             int ow = originalImage.Width;
 69             int oh = originalImage.Height;
 70
 71             //新建一个bmp图片
 72             System.Drawing.Image bitmap = new System.Drawing.Bitmap(towidth, toheight);
 73             System.Drawing.Image bitmap2 = new System.Drawing.Bitmap(towidth, toheight);
 74             //新建一个画板
 75             System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap);
 76
 77
 78             //设置高质量插值法
 79             g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
 80
 81             //设置高质量,低速度呈现平滑程度
 82             g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
 83
 84             //清空画布并以透明背景色填充
 85             g.Clear(System.Drawing.Color.Transparent);
 86
 87             //在指定位置并且按指定大小绘制原图片的指定部分
 88             g.DrawImage(originalImage, new System.Drawing.Rectangle(0, 0, towidth, toheight));
 89
 90             try
 91             {
 92                 //以jpg格式保存缩略图
 93                 FileExt = Path.GetFileNameWithoutExtension(originalImagePath);
 94 　　　　　　　　　　//用新建立的image对象拷贝bitmap对象 让g对象可以释放资源
 95                 draw = Graphics.FromImage(bitmap2);
 96                 draw.DrawImage(bitmap, 0, 0);
 97
 98             }
 99             catch (System.Exception e)
100             {
101                 throw e;
102             }
103             finally
104             {
105                 originalImage.Dispose();
106                 bitmap.Dispose();
107                 g.Dispose();
108 　　　　　　　　　　//保存调整在这里即可
109                 bitmap2.Save(HttpContext.Current.Server.MapPath(thumbnailPath) + FileExt + ".jpg", System.Drawing.Imaging.ImageFormat.Jpeg);
110             }
111         }