ajax +.net mvc 多图片上传加预览

ajax +.net mvc 多图片上传加预览

@{
    ViewBag.Title = "Index";
    Layout = null;
}

<!DOCTYPE HTML>
<html>

<head>
    <meta charset="UTF-8">
    <title> 上传多张图片</title>

</head>

<body>
    <script src="~/scripts/jquery-3.3.1.js"></script>
    <script type="text/javascript">
            //选择图片，预览
            function xmTanUploadImg(obj) {
                var imgTypes = new Array();
                imgTypes[0] = "JPG";
                imgTypes[1] = "ICO";
                imgTypes[2] = "PNG";
                imgTypes[3] = "GIF";
                imgTypes[4] = "JPEG";
                imgTypes[5] = "TGA";
                var  num=0;//选错图片格式的个数
                var fl = obj.files.length;
                if(fl<=7){

                for(var i = 0; i < fl; i++) {
                    var file = obj.files[i];
                    //判断图片格式
                    var filename = obj.files[i].name;
                    imgType = filename.substring(filename.lastIndexOf(".") + 1, file.length)
                    var reader = new FileReader();
                    //判断是否是图片格式
                    if (imgType.toUpperCase()==imgTypes[0]||imgType.toUpperCase()==imgTypes[1]||imgType.toUpperCase()==imgTypes[2]||imgType.toUpperCase()==imgTypes[3]||imgType.toUpperCase()==imgTypes[4]||imgType.toUpperCase()==imgTypes[5]) {
                        reader.onload = function(e) {
                        img = document.createElement("img");
                        img.src = this.result;
                        img.style.width = "80px";
                        img.style.height = "100px";
                        document.getElementById("showimg").appendChild(img);
                       $("#upload").attr("disabled",false);
                    }
                    } else{
                            num++;
                        alert("你选择的图片格式不正确:"+num+"张图片格式不正确");
                        $("#upload").attr("disabled",true);
                    }

                    reader.readAsDataURL(file);
                }
                }else{

                    alert("每次只能上传7张图片");
                }

            }

            function Upload() {        
                var param = new FormData(($("#form")[0]));
                $.ajax({
                    url: "/Upload.ashx",
                    data: param,
                    type:"post",
                    processData: false,    
                    contentType: false,
                    success: function (data) {
                        alert(data)
                    }


                })
            }
    </script>

    <form method="post" enctype="multipart/form-data" id="form" >
        <input type="file" name="file" id="file" multiple="multiple" onchange="xmTanUploadImg(this)" />
        <input  type="button" value="上传" onclick="Upload()" />
    </form>
    <!--图片显示位置-->
    <div id="showimg">

    </div>

</body>

一般处理程序

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;

namespace WebApplication5
{
    /// <summary>
    /// Upload 的摘要说明
    /// </summary>
    public class Upload : IHttpHandler
    {

        public void ProcessRequest(HttpContext context)
        {
            context.Response.ContentType = "text/plain";

            var num = context.Request.Files.Count;

            for (int i = 0; i < num; i++)
            {
                HttpPostedFile file = context.Request.Files[i];
                //上传的文件保存到目录(为了保证文件名不重复，加个Guid)
                string path = "/Upload/" + Guid.NewGuid().ToString() + file.FileName;
                file.SaveAs(context.Request.MapPath(path));//必须得是相对路径

            }
            context.Response.Write("上传成功");
        }

        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }
}

这个后台没有对是否是图片进行验证 所以 实际用到 要加上类型判断