C#图片上传（c#传输图片）

由于需要图片上传的功能，所以花了一些时间网上找相关资料终于搞定，效果图如下：

C#图片上传（c#传输图片）

下面的是解决方案截图和上传的图片截图：

C#图片上传（c#传输图片）

具体实现代码如下：

1.界面代码

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 <%@ page language="c#" autoeventwireup="true" codebehind="uploadpic.aspx.cs" inherits="pic_try.uploadpic" %> <!doctype html public "-//w3c//dtd xhtml 1.0 transitional//en" "http://www.w3.org/tr/xhtml1/dtd/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server"> <title>图片上传和显示</title> <style type="text/css"> .pic_text{ color:red;} .pic_label { color:gray; margin-top:5px; margin-bottom:5px;} .pic_image { margin:5px;} </style> </head> <body> <form id="form1" runat="server"> <div class="pic_image"><asp:image id="pic" runat="server" /></div> <div><asp:fileupload id="pic_upload" runat="server" /><asp:label id="lbl_pic" runat="server" class="pic_text"></asp:label></div> <div class="pic_label">上传图片格式为.jpg, .gif, .bmp,.png,图片大小不得超过8m</div> <div><asp:button id="btn_upload" runat="server" text="上传" onclick="btn_upload_click"/></div> </form> </body> </html>

2.后台代码uploadpic.aspx.cs

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 using system; using system.collections.generic; using system.linq; using system.web; using system.web.ui; using system.web.ui.webcontrols; using system.io; using system.security.cryptography; using system.web.security; namespace pic_try { public partial class uploadpic : system.web.ui.page { protected void page_load(object sender, eventargs e) { } protected void btn_upload_click(object sender, eventargs e) { boolean fileok = false; if (pic_upload.hasfile)//验证是否包含文件 { //取得文件的扩展名,并转换成小写 string fileextension = path.getextension(pic_upload.filename).tolower(); //验证上传文件是否图片格式 fileok = isimage(fileextension); if (fileok) { //对上传文件的大小进行检测，限定文件最大不超过8m if (pic_upload.postedfile.contentlength < 8192000) { string filepath = "/images/"; if (directory.exists(server.mappath(filepath)) == false)//如果不存在就创建file文件夹 { directory.createdirectory(server.mappath(filepath)); } string virpath = filepath + createpasswordhash(pic_upload.filename, 4) + fileextension;//这是存到服务器上的虚拟路径 string mappath = server.mappath(virpath);//转换成服务器上的物理路径 pic_upload.postedfile.saveas(mappath);//保存图片 //显示图片 pic.imageurl = virpath; //清空提示 lbl_pic.text = ""; } else { pic.imageurl = ""; lbl_pic.text = "文件大小超出8m！请重新选择！"; } } else { pic.imageurl = ""; lbl_pic.text = "要上传的文件类型不对！请重新选择！"; } } else { pic.imageurl = ""; lbl_pic.text = "请选择要上传的图片！"; } } /// <summary> /// 验证是否指定的图片格式 /// </summary> /// <param name="str"></param> /// <returns></returns> public bool isimage(string str) { bool isimage = false; string thestr = str.tolower(); //限定只能上传jpg和gif图片 string[] allowextension = { ".jpg", ".gif", ".bmp",".png" }; //对上传的文件的类型进行一个个匹对 for (int i = 0; i < allowextension.length; i++) { if (thestr == allowextension[i]) { isimage = true; break; } } return isimage; } /// <summary> /// 创建一个指定长度的随机salt值 /// </summary> public string createsalt(int saltlenght) { //生成一个加密的随机数 rngcryptoserviceprovider rng = new rngcryptoserviceprovider(); byte[] buff = new byte[saltlenght]; rng.getbytes(buff); //返回一个base64随机数的字符串 return convert.tobase64string(buff); } /// <summary> /// 返回加密后的字符串 /// </summary> public string createpasswordhash(string pwd, int saltlenght) { string strsalt = createsalt(saltlenght); //把密码和salt连起来 string saltandpwd = string.concat(pwd, strsalt); //对密码进行哈希 string hashenpwd = formsauthentication.hashpasswordforstoringinconfigfile(saltandpwd, "sha1"); //转为小写字符并截取前16个字符串 hashenpwd = hashenpwd.tolower().substring(0, 16); //返回哈希后的值 return hashenpwd; } } }

3.最后防止上传大文件图片时报错，配置文件添加配置web.config

1 2 3 4 5 6 7 8 9 10 11 12 13 14 <?xml version="1.0" encoding="utf-8"?>  <configuration> <system.web> <compilation debug="true" targetframework="4.0" /> <httpruntime executiontimeout="240" maxrequestlength="8192000"/> </system.web> </configuration>