【ASP.NET 基础】图片上传和显示
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
UploadPic.aspx
<%@ 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>
