JS异步上传Excel 并使用NPOI进行读写操作

实现功能

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导入——客户端使用 ajaxfileupload.js 插件实现Excel的异步上传，并在服务端解析成JSON字符串返回页面

导出——将页面中的grid表拼接成JSON串上传至服务器，在服务端新建Excel并将数据导入，随后返回url给用户下载

客户端（Test.aspx）

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页面上需要实现的效果是显示一个“导入”按钮，hover时会显示标准格式图片，点击触发上传事件，选择Excel文件后上传到服务器，HTML代码如下

PS：使用了Bootstrap样式，也可以自己定义。“loadingDiv”为加载控件，“downfile”存放返回的url，提供下载。附送loading.gif资源，也可以用CSS绘制，可参考我的第一篇博文几个单元素Loading动画解构~

 <div id="loadingDiv"><div id="loadingCont"><img src="assets/loading.gif"/><span style="">请稍等...</span></div></div>
 <a id="downfile"><span></span></a>

 <div class="col-md-2 col-xs-4">
     <button class="btn btn-info" id="tab2-btn-import"><img src="assets/计算四参数.png"/><i class="icon-reply"></i>导入</button>
     <input type="file" name="file" id="upload-file" accept="application/vnd.openxmlformats-officedocument.spreadsheetml.sheet, application/vnd.ms-excel"/>
 </div>

 <div class="col-md-2 col-xs-4"><button class="btn btn-primary" id="tab2-btn-export"><i class="icon-share-alt"></i>导出</button></div>

CSS代码如下

#loadingDiv{
    width:100%;
    height:100%;
    position:absolute;
    z-index:;
    display:none;
}
#loadingCont{
    width:130px;
    height:50px;
    position:relative;
    padding-left:10px;
    left:calc(50% - 50px);
    top:40%;
    border-radius:3px;
    background-color:#fff;
}
#loadingCont img{
    width:50px;
    height:50px;
}
#loadingCont span{
    position:relative;
    top:2px;
    color: #696969;
    font-family:"Microsoft YaHei";
}

#tab2-btn-import{
    position:relative;
}
#tab2-btn-import img{
    position:absolute;
    top:-70px;
    left:-145px;
    border:1px solid #999;
    display:none;
}

#upload-file{
    width:80px;
    height:35px;
    position:absolute;
    top:;
    left:calc(50% - 40px);
    cursor:pointer;
    opacity:;
}

css

实现hover效果和导入、导出的JS代码：

     //Uploadify
     //导入
     $("#upload-file").change(ImportExcel);
     function ImportExcel() {
         $("#loadingDiv").show();   //显示加载控件;
         $.ajaxFileUpload(
             {
                 url: 'Test.aspx', //用于文件上传的服务器端请求地址
                 secureuri: false, //是否需要安全协议，一般设置为false
                 fileElementId: 'upload-file', //文件上传域的ID
                 dataType: 'JSON', //返回值类型 一般设置为json
                 success: function (data, status)  //服务器成功响应处理函数
                 {
                     if (status == "success") {
                         try {
                             var jsondata = $.parseJSON(data);
                             if (jsondata[0]["源坐标X"] == undefined || jsondata[0]["源坐标Y"] == undefined || jsondata[0]["目标坐标X"] == undefined || jsondata[0]["目标坐标Y"] == undefined) {
                                 alert("Excel格式有误，请按标准格式导入");
                             }
                             else {
                                 var rows_be = grid.count();
                                 for (var i = 1; i <= rows_be ; i++) {
                                     grid.removeRow(i);   //grid.clear()不会清空，再使用addRow时仍会显示之前数据，暂时解决办法为暴力清空
                                 }
                                 for (var i = 0; i < jsondata.length; i++) {
                                     grid.addRow({ '点名': jsondata[i]["点名"], "源坐标X": jsondata[i]["源坐标X"], "源坐标Y": jsondata[i]["源坐标Y"], "目标坐标X": jsondata[i]["目标坐标X"], "目标坐标Y": jsondata[i]["目标坐标Y"] });
                                 }
                             }
                         }
                         catch (e) {
                             console.log(e);
                             alert("Excel格式有误，请按标准格式导入");
                         }
                         finally {
                             $("#upload-file").change(ImportExcel);    //ajaxFileUpload插件执行完成会新建，需要重新绑定事件
                             $("#loadingDiv").hide();   //数据准备完成，隐藏加载控件
                         }
                     }
                 },
                 error: function (data, status, e)//服务器响应失败处理函数
                 {
                     console.log(e);
                     $("#loadingDiv").hide();
                 }
             });
     }

     //hover时显示提示
     $("#upload-file").hover(function () { $("#tab2-btn-import img").show(); }, function () { $("#tab2-btn-import img").hide(); });

     //导出
     $("#tab2-btn-export").on("click", ExportExcel);
     function ExportExcel() {
         $("#loadingDiv").show();
         $.ajax({
             type: 'post',
             url: 'Test.aspx/Export2Excel',
             data: "{'RowData':'" + JSON.stringify(grid.getAll()) + "'}",
             dataType: 'json',
             contentType: 'application/json;charset=utf-8',
             success: function (data) {
                 console.log(data);
                 if (data.d == "") {
                     alert("该时段无历史数据");
                 }
                 else {
                     var jsondata = $.parseJSON(data.d);
                     if (jsondata["result"] != "fail") downloadFile(window.location.host + "\\文件路径，此处隐藏\\" + jsondata["result"]);
                 }
                 $("#loadingDiv").hide();
             },
             error: function (msg) {
                 console.log(msg);
                 $("#loadingDiv").hide();
             }
         });
     }
 });
 //自动下载文件
 function downloadFile(docurl) {
     $("#downfile").attr("href", "http://" + docurl);
     $("#downfile span").click();
 }

PS：对于ajaxFileUpload插件的使用可以看看这篇文章jQuery插件之ajaxFileUpload，因为插件代码很短所以在这里贴出来，各位新建一个js文件粘进去即可。

 jQuery.extend({

     createUploadIframe: function(id, uri)
     {
         //create frame
         var frameId = 'jUploadFrame' + id;

         if(window.ActiveXObject) {
             var io = document.createElement('<iframe id="' + frameId + '" name="' + frameId + '" />');
             if(typeof uri== 'boolean'){
                 io.src = 'javascript:false';
             }
             else if(typeof uri== 'string'){
                 io.src = uri;
             }
         }
         else {
             var io = document.createElement('iframe');
             io.id = frameId;
             io.name = frameId;
         }
         io.style.position = 'absolute';
         io.style.top = '-1000px';
         io.style.left = '-1000px';

         document.body.appendChild(io);

         return io
     },
     createUploadForm: function(id, fileElementId)
     {
         //create form
         var formId = 'jUploadForm' + id;
         var fileId = 'jUploadFile' + id;
         var form = $('<form  action="" method="POST" name="' + formId + '" id="' + formId + '" enctype="multipart/form-data"></form>');
         var oldElement = $('#' + fileElementId);
         var newElement = $(oldElement).clone();
         $(oldElement).attr('id', fileId);
         $(oldElement).before(newElement);
         $(oldElement).appendTo(form);
         //set attributes
         $(form).css('position', 'absolute');
         $(form).css('top', '-1200px');
         $(form).css('left', '-1200px');
         $(form).appendTo('body');
         return form;
     },
     addOtherRequestsToForm: function(form,data)
     {
         // add extra parameter
         var originalElement = $('<input type="hidden" name="" value="">');
         for (var key in data) {
             name = key;
             value = data[key];
             var cloneElement = originalElement.clone();
             cloneElement.attr({'name':name,'value':value});
             $(cloneElement).appendTo(form);
         }
         return form;
     },

     ajaxFileUpload: function(s) {
         // TODO introduce global settings, allowing the client to modify them for all requests, not only timeout
         s = jQuery.extend({}, jQuery.ajaxSettings, s);
         var id = new Date().getTime()
         var form = jQuery.createUploadForm(id, s.fileElementId);
         if ( s.data ) form = jQuery.addOtherRequestsToForm(form,s.data);
         var io = jQuery.createUploadIframe(id, s.secureuri);
         var frameId = 'jUploadFrame' + id;
         var formId = 'jUploadForm' + id;
         // Watch for a new set of requests
         if ( s.global && ! jQuery.active++ )
         {
             jQuery.event.trigger( "ajaxStart" );
         }
         var requestDone = false;
         // Create the request object
         var xml = {}
         if ( s.global )
             jQuery.event.trigger("ajaxSend", [xml, s]);
         // Wait for a response to come back
         var uploadCallback = function(isTimeout)
         {
             var io = document.getElementById(frameId);
             try
             {
                 if(io.contentWindow)
                 {
                     xml.responseText = io.contentWindow.document.body?io.contentWindow.document.body.innerHTML:null;
                     xml.responseXML = io.contentWindow.document.XMLDocument?io.contentWindow.document.XMLDocument:io.contentWindow.document;

                 }else if(io.contentDocument)
                 {
                     xml.responseText = io.contentDocument.document.body?io.contentDocument.document.body.innerHTML:null;
                     xml.responseXML = io.contentDocument.document.XMLDocument?io.contentDocument.document.XMLDocument:io.contentDocument.document;
                 }
             }catch(e)
             {
                 jQuery.handleError(s, xml, null, e);
             }
             if ( xml || isTimeout == "timeout")
             {
                 requestDone = true;
                 var status;
                 try {
                     status = isTimeout != "timeout" ? "success" : "error";
                     // Make sure that the request was successful or notmodified
                     if ( status != "error" )
                     {
                         // process the data (runs the xml through httpData regardless of callback)
                         var data = jQuery.uploadHttpData( xml, s.dataType );
                         // If a local callback was specified, fire it and pass it the data
                         if ( s.success )
                             s.success( data, status );

                         // Fire the global callback
                         if( s.global )
                             jQuery.event.trigger( "ajaxSuccess", [xml, s] );
                     } else
                         jQuery.handleError(s, xml, status);
                 } catch(e)
                 {
                     status = "error";
                     jQuery.handleError(s, xml, status, e);
                 }

                 // The request was completed
                 if( s.global )
                     jQuery.event.trigger( "ajaxComplete", [xml, s] );

                 // Handle the global AJAX counter
                 if ( s.global && ! --jQuery.active )
                     jQuery.event.trigger( "ajaxStop" );

                 // Process result
                 if ( s.complete )
                     s.complete(xml, status);

                 jQuery(io).unbind()

                 setTimeout(function()
                 {    try
                     {
                         $(io).remove();
                         $(form).remove();

                     } catch(e)
                     {
                         jQuery.handleError(s, xml, null, e);
                     }

                 }, 100)

                 xml = null

             }
         }
         // Timeout checker
         if ( s.timeout > 0 )
         {
             setTimeout(function(){
                 // Check to see if the request is still happening
                 if( !requestDone ) uploadCallback( "timeout" );
             }, s.timeout);
         }
         try
         {
             // var io = $('#' + frameId);
             var form = $('#' + formId);
             $(form).attr('action', s.url);
             $(form).attr('method', 'POST');
             $(form).attr('target', frameId);
             if(form.encoding)
             {
                 form.encoding = 'multipart/form-data';
             }
             else
             {
                 form.enctype = 'multipart/form-data';
             }
             $(form).submit();

         } catch(e)
         {
             jQuery.handleError(s, xml, null, e);
         }
         if(window.attachEvent){
             document.getElementById(frameId).attachEvent('onload', uploadCallback);
         }
         else{
             document.getElementById(frameId).addEventListener('load', uploadCallback, false);
         }
         return {abort: function () {}};

     },

     uploadHttpData: function( r, type ) {
         var data = !type;
         data = type == "xml" || data ? r.responseXML : r.responseText;
         // If the type is "script", eval it in global context
         if ( type == "script" )
             jQuery.globalEval( data );
         // Get the JavaScript object, if JSON is used.
         if ( type == "json" )
         {
             // If you add mimetype in your response,
             // you have to delete the '<pre></pre>' tag.
             // The pre tag in Chrome has attribute, so have to use regex to remove
             var data = r.responseText;
             var rx = new RegExp("<pre.*?>(.*?)</pre>","i");
             var am = rx.exec(data);
             //this is the desired data extracted
             var data = (am) ? am[1] : "";    //the only submatch or empty
             eval( "data = " + data );
         }
         // evaluate scripts within html
         if ( type == "html" )
             jQuery("<div>").html(data).evalScripts();
         //alert($('param', data).each(function(){alert($(this).attr('value'));}));
         return data;
     },

     handleError: function( s, xhr, status, e )      {
         // If a local callback was specified, fire it
     if ( s.error ) {
         s.error.call( s.context || s, xhr, status, e );
     }  

         // Fire the global callback
     if ( s.global ) {
         (s.context ? jQuery(s.context) : jQuery.event).trigger( "ajaxError", [xhr, s, e] );
     }
 }
 })

ajaxfileupload.js

服务端（Test.aspx.cs）

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在服务端做Excel解析常用的有三种方法：

一是使用微软的开放式数据库接口技术OleDb，建立连接后可像数据库一样操作Excel，但是个人测试发现在网页文件上传成功后，OleDb接口无法读取文件，页面报跨域错误（本机调试通过，发布后报错），但路径却是同源的，一直不知道问题在哪儿，希望有了解的前辈指点指点。

二是使用Com组件方式读取，这种方式也尝试过，读取速度相对来说非常慢，故舍弃。

三是使用第三方的NPOI插件。因为前两种方法依赖于微软的Office环境，所以在使用时需要在服务器上安装Office，而这种方法只要下载并引用dll文件即可，优势明显。并且个人测试效率也很高，使用方便，故采用。

以下为服务端代码：

     protected void Page_Load(object sender, EventArgs e)
     {
         HttpFileCollection files = Request.Files;
         string msg = string.Empty;
         string error = string.Empty;
         //string docurl;
         if (files.Count > )
         {
             string path = Server.MapPath("~/项目目录/uploadfile/") + Path.GetFileName(files[].FileName);

             files[].SaveAs(path);
             //msg = "成功！文件大小为:" + files[0].ContentLength;

             //解析Excel
             string excelgrid = "";
             using (ExcelHelper excelHelper = new ExcelHelper(path))
             {
                 DataTable dt = excelHelper.ExcelToDataTable("MySheet", true);
                 excelgrid = JsonHepler.ToJson(dt);
             }
             //string res = "{ error:'" + error + "', msg:'" + msg + "',excelgrid:'" + excelgrid + "'}";
             Response.Write(excelgrid);
             Response.End();
         }
     }

     [WebMethod]
     public static string Export2Excel(string RowData)
     {
         try
         {
             DataTable dt = JsonHepler.JsonToDataTable(RowData);
             string docname = string.Format("{0:yyyyMMddHHmmssffff}", DateTime.Now) + ".xlsx";
             string docurl = AppDomain.CurrentDomain.BaseDirectory + "项目目录\\downloadfile\\" + docname;
             int count = ;

             using (ExcelHelper excelHelper = new ExcelHelper(docurl))
             {
                 count = excelHelper.DataTableToExcel(dt,"MySheet", true);
             }

             if (count >= ) return "{\"result\":\""+ docname + "\"}";
             else return "{'result':'fail'}";
         }
         catch(Exception)
         {
             throw;
         }
     }

NPOI为第三方插件，关于NPOI的使用可以参考NPOI读写Excel，文章中也提供了读取/写入的工具类。同时提供NPOI的下载地址，下载后根据.net版本引入dll即可，在此我使用的是4.0，所以引用了 Net40 文件夹中的数个dll。

接下来我们就可以调试发布啦~