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：
下面的是解决方案截图和上传的图片截图：
具体实现代码如下：
1.界面代码
<%@ 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
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
<? xml version = "1.0" encoding = "utf-8" ?>
<!--
有关如何配置 asp.net 应用程序的详细消息，请访问
http://go.microsoft.com/fwlink/?linkid=169433
-->
< configuration >
< system.web >
< compilation debug = "true" targetframework = "4.0" />
< httpruntime executiontimeout = "240" maxrequestlength = "8192000" />
</ system.web >
</ configuration >
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持服务器之家。
dy("nrwz");