首先创建一个网页，网页中添加如下代码。

Upload File using Jquery AJAX in Asp.net
      
     
                
       
                  
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接着在添加jquery代码

$("#btnUpload").click(function (evt) {              var fileUpload = $("#fupload").get(0);              var files = fileUpload.files;                var data = new FormData();              for (var i = 0; i < files.length; i++) {                  data.append(files[i].name, files[i]);              }                $.ajax({                  url: "FileUploadHandler.ashx",                  type: "POST",                  data: data,                  contentType: false,                  processData: false,                  success: function (result) { alert(result); },                  error: function (err) {                      alert(err.statusText)                  }              });                evt.preventDefault();          });

FileUploadHandler.ashx中的代码

<%@ WebHandler Language="C#" Class="FileUploadHandler" %>         using System;    using System.Web;         public class FileUploadHandler : IHttpHandler  {             public void ProcessRequest (HttpContext context)      {            if (context.Request.Files.Count > 0)            {                HttpFileCollection files = context.Request.Files;                for (int i = 0; i < files.Count; i++)                {                    HttpPostedFile file = files[i];                    string fname = context.Server.MapPath("~/uploads/" + file.FileName);                    file.SaveAs(fname);                }                context.Response.ContentType = "text/plain";                context.Response.Write("File Uploaded Successfully!");            }             }             public bool IsReusable      {            get           {                return false;            }        }         }

最后效果如下：