上传图片并生成缩略图的ASP.NET2.0代码！

1 <%@ Page Language="C#" ResponseEncoding="gb2312" %>
2 <%@ import Namespace="System" %>
3 <%@ import Namespace="System.IO" %>
4 <%@ import Namespace="System.Drawing" %>
5 <%@ import Namespace="System.Drawing.Imaging" %>
6 <script runat="server">
7
8 void Page_Load(Object sender, EventArgs e)
9 {
10 if(!Page.IsPostBack)
11 {
12 ImgPreview.Visible=false;
13 }
14 }
15 void GetThumbnailImage(int width,int height,string strInfo,int left,int right)
16 {
17 string file="Uploads/"+uploadFile.PostedFile.FileName.Substring(uploadFile.PostedFile.FileName.LastIndexOf('\\')+1);
18 string newfile="Uploads/"+uploadFile.PostedFile.FileName.Substring(uploadFile.PostedFile.FileName.LastIndexOf('\\')+1)+".jpg";
19 string strAdd=strInfo;
20 System.Drawing.Image oldimage = System.Drawing.Image.FromFile(Server.MapPath(file));
21 System.Drawing.Image thumbnailImage =
22 oldimage.GetThumbnailImage(width, height,new System.Drawing.Image.GetThumbnailImageAbort(ThumbnailCallback), IntPtr.Zero);
23 Response.Clear();
24 Bitmap output=new Bitmap(thumbnailImage);
25 Graphics g=Graphics.FromImage(output);
26 g.DrawString(strAdd,new Font("Courier New", 14),new SolidBrush(Color.Red),left,right);
27 output.Save(Server.MapPath(newfile),System.Drawing.Imaging.ImageFormat.Jpeg);
28 Response.ContentType = "image/gif";
29 ImgPreview.Visible=true;
30 ImgPreview.ImageUrl=newfile;
31 }
32 bool ThumbnailCallback()
33 {
34 return true;
35 }
36
37 void Button_Click(object sender, EventArgs e)
38 {
39 int width,height,left,right;
40 string strAddInfo=txtAddInfo.Text;
41 width=Int32.Parse(txtWidth.Text);
42 height=Int32.Parse(txtHeight.Text);
43 left=Int32.Parse(txtLeft.Text);
44 right=Int32.Parse(txtRight.Text);
45 if(!(uploadFile.PostedFile.ContentLength>0))
46 {
47 lblErrInfo.Text="没有选择文件";
48 }
49 else
50 {
51
52 string path = Server.MapPath("./Uploads/"+uploadFile.PostedFile.FileName.Substring(uploadFile.PostedFile.FileName.LastIndexOf('\\')+1));
53 if(File.Exists(path))
54 {
55 lblErrInfo.Text="已经有同名文件";
56 }
57 else
58 {
59 uploadFile.PostedFile.SaveAs(path);
60 GetThumbnailImage(width,height,strAddInfo,left,right);
61 }
62 }
63 }
64 </script>
65 <html>
66 <head>
67 </head>
68 <body>
69 <form method="post" enctype="multipart/form-data" runat="server">
70 <p>
71 <input id="uploadFile" type="file" runat="server" />
72 <asp:Label id="lblErrInfo" runat="server" forecolor="Red"></asp:Label>
73 </p>
74 <p>
75 <asp:TextBox id="txtWidth" runat="server" Width="40px">100</asp:TextBox>
76  height:<asp:TextBox id="txtHeight" runat="server" Width="40px">150</asp:TextBox>
77
78 </p>
79 <p>
80 添加信息：<asp:TextBox id="txtAddInfo" runat="server">AspxBoy.Com</asp:TextBox>
81 </p>
82 <p>
83 信息位置：left:<asp:TextBox id="txtLeft" runat="server" Width="40px">10</asp:TextBox>
84  right:<asp:TextBox id="txtRight" runat="server" Width="40px">135</asp:TextBox>
85 </p>
86 <p>
87
88 <input id="button" type="button" value="上传生成缩略图" onServerClick="Button_Click" runat="server" />
89 </p>
90 <p><asp:Image id="ImgPreview" runat="server"></asp:Image>
91 </p>
92 
93 </form>
94 </body>
95 </html>