ASP.NET图片上传实例（附源码）

2020-01-17 23:04:06

字体：大中小

来源：转载

供稿：网友

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：

下面是代码：
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

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

<?xml version="1.0" encoding="utf-8"?><!-- 如何配置 ASP.NET 应用程序的详细消息 --><configuration> <system.web> <compilation debug="true" targetFramework="4.0" /> <httpRuntime executionTimeout="240" maxRequestLength="8192000"/> </system.web></configuration>

ASP.NET图片自动上传和局部刷新显示的源码下载。

希望大家喜欢这篇文章。

上一篇：ASP.NET验证码实现（附源码）

下一篇：C#实现把图片下载到服务器代码