1 #region 上传图片生成缩略图
2 /// <summary>
3 /// 上传图片
4 /// </summary>
5 /// <param name="sender"></param>
6 /// <param name="e"></param>
7 public void btnUpload_Click(object sender, EventArgs e)
8 {
9 //检查上传文件的格式是否有效
10 if (this.fudPhoto.PostedFile.ContentType.ToLower().IndexOf("image") < 0)
11 {
12 Response.Write("<script>alert('上传图片格式无效!');window.location.href='LES_ApplyTopActivityAdd.aspx';</script>");
13 return;
14 }
15 string FileNmae;
16 string FileNameS;
17 string name = fudPhoto.PostedFile.FileName;//客户端文件路径
18 FileInfo file = new FileInfo(name);
19 string fileName = file.Name;
20 string ExtName = getFileExt(fileName).ToUpper();
21 //生成原图
22 Byte[] oFileByte = new byte[this.fudPhoto.PostedFile.ContentLength];
23 System.IO.Stream oStream = this.fudPhoto.PostedFile.InputStream;
24 System.Drawing.Image oImage = System.Drawing.Image.FromStream(oStream);
25 int towidth = 140;//设置缩略图初始高度
26 int toheight = 140;//设置缩略图初始宽度
27 int x = 0;
28 int y = 0;
29 int ow = oImage.Width;
30 int oh = oImage.Height;
31
32 if (ow == 640 && ow == 640)
33 {
34 //按比例计算出缩略图的宽度和高度
35
36 if (((double)oImage.Width / (double)oImage.Height) > ((double)towidth / (double)toheight))
37 {
38 oh = oImage.Height;
39 ow = oImage.Height * towidth / toheight;
40 y = 0;
41 x = (oImage.Width - ow) / 2;
42 }
43 else
44 {
45 ow = oImage.Width;
46 oh = oImage.Width * toheight / towidth;
47 x = 0;
48 y = (oImage.Height - oh) / 2;
49 }
50 //生成缩略原图
51 Bitmap tImage = new Bitmap(towidth, toheight);
52 Graphics g = Graphics.FromImage(tImage);
53 g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High; //设置高质量插值法
54 g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;//设置高质量,低速度呈现平滑程度
55 g.Clear(Color.Transparent); //清空画布并以透明背景色填充
56 g.DrawImage(oImage, new Rectangle(0, 0, towidth, toheight), new Rectangle(0, 0, ow, oh), GraphicsUnit.Pixel);
57
58 FileNmae = DateTime.Now.ToShortDateString().Replace("-", "") + DateTime.Now.Hour.ToString() + DateTime.Now.Minute.ToString() + DateTime.Now.Second.ToString() + DateTime.Now.Millisecond.ToString() + "." + ExtName; //保存原图的物理路径
59 string oFullName = Server.MapPath("/uploadfiles//" + FileNmae);
60
61 FileNameS = FileNmae + "-S" + ".JPG"; //保存缩略图的物理路径
62 string tFullName = Server.MapPath("/uploadfiles//" + FileNameS);
63 try
64 {
65 //以JPG格式保存图片
66 oImage.Save(oFullName, System.Drawing.Imaging.ImageFormat.Jpeg);
67 tImage.Save(tFullName, System.Drawing.Imaging.ImageFormat.Jpeg);
68
69 //lbMessage.Text = "提示：文件”" + FileNmae + "“成功上传，并生成”" + FileNameS + "“缩略图，文件类型为：" +
70 // fudPhoto.PostedFile.ContentType + "，文件大小为：" + fudPhoto.PostedFile.ContentLength + "B";
71 lbMessage.Text = "提示：文件成功上传，并生成”" + FileNameS + "“缩略图！";
72 string PIC = FileNmae;
73 ViewState["pic"] = PIC;
74 }
75 catch (Exception ex)
76 {
77 throw ex;
78 }
79 finally
80 {
81 //释放资源
82 oImage.Dispose();
83 g.Dispose();
84 tImage.Dispose();
85 }
86 }
87 else
88 {
89 lbMessage.Text = "提示：图片的尺寸应该是640x640";
90 }
91 }
92 private string getFileExt(string fileName)
93 {
94 if (fileName.IndexOf(".") == -1)
95 return "";
96 string[] temp = fileName.Split('.');
97 return temp[temp.Length - 1].ToLower();
98 }
99 #endregion
100 }
如图效果图：
