I have a large(ish) form in MVC.
I need to be able to generate an excel file containing data from a subset of that form.
The tricky bit is that this shouldn't affect the rest of the form and so I want to do it via AJAX. I've come across a few questions on SO that seem to be related, but I can't quite work out what the answers mean.
This one seems the closest to what I'm after: asp-net-mvc-downloading-excel - but I'm not sure I understand the response, and it is a couple years old now. I also came across another article (can't find it anymore) about using an iframe to handle the file download, but I'm not sure how to get this working with MVC.
My excel file returns fine if I'm doing a full post back but I can't get it working with AJAX in mvc.
You can't directly return a file for download via an AJAX call so, an alternative approach is to to use an AJAX call to post the related data to your server. You can then use server side code to create the Excel File (I would recommend using EPPlus or NPOI for this although it sounds as if you have this part working).
UPDATE September 2016
My original answer (below) was over 3 years old, so I thought I would update as I no longer create files on the server when downloading files via AJAX however, I have left the original answer as it may be of some use still depending on your specific requirements.
A common scenario in my MVC applications is reporting via a web page that has some user configured report parameters (Date Ranges, Filters etc.). When the user has specified the parameters they post them to the server, the report is generated (say for example an Excel file as output) and then I store the resulting file as a byte array in the TempData bucket with a unique reference. This reference is passed back as a Json Result to my AJAX function that subsequently redirects to separate controller action to extract the data from TempData and download to the end users browser.
To give this more detail, assuming you have a MVC View that has a form bound to a Model class, lets call the Model ReportVM.
First, a controller action is required to receive the posted model, an example would be:
public ActionResult PostReportPartial(ReportVM model){
// Validate the Model is correct and contains valid data
// Generate your report output based on the model parameters
// This can be an Excel, PDF, Word file - whatever you need.
// As an example lets assume we've generated an EPPlus ExcelPackage
ExcelPackage workbook = new ExcelPackage();
// Do something to populate your workbook
// Generate a new unique identifier against which the file can be stored
string handle = Guid.NewGuid().ToString();
using(MemoryStream memoryStream = new MemoryStream()){
workbook.SaveAs(memoryStream);
memoryStream.Position = 0;
TempData[handle] = memoryStream.ToArray();
}
// Note we are returning a filename as well as the handle
return new JsonResult() {
Data = new { FileGuid = handle, FileName = "TestReportOutput.xlsx" }
};
}
The AJAX call that posts my MVC form to the above controller and receives the response looks like this:
$ajax({
cache: false,
url: '/Report/PostReportPartial',
data: _form.serialize(),
success: function (data){
var response = JSON.parse(data);
window.location = '/Report/Download?fileGuid=' + response.FileGuid
+ '&filename=' + response.FileName;
}
})
The controller action to handle the downloading of the file:
[HttpGet]
public virtual ActionResult Download(string fileGuid, string fileName)
{
if(TempData[fileGuid] != null){
byte[] data = TempData[fileGuid] as byte[];
return File(data, "application/vnd.ms-excel", fileName);
}
else{
// Problem - Log the error, generate a blank file,
// redirect to another controller action - whatever fits with your application
return new EmptyResult();
}
}
One other change that could easily be accommodated if required is to pass the MIME Type of the file as a third parameter so that the one Controller action could correctly serve a variety of output file formats.
This removes any need for any physical files to created and stored on the server, so no housekeeping routines required and once again this is seamless to the end user.
Note, the advantage of using TempData rather than Session is that once TempData is read the data is cleared so it will be more efficient in terms of memory usage if you have a high volume of file requests. See TempData Best Practice.
ORIGINAL Answer
You can't directly return a file for download via an AJAX call so, an alternative approach is to to use an AJAX call to post the related data to your server. You can then use server side code to create the Excel File (I would recommend using EPPlus or NPOI for this although it sounds as if you have this part working).
Once the file has been created on the server pass back the path to the file (or just the filename) as the return value to your AJAX call and then set the JavaScript window.location to this URL which will prompt the browser to download the file.
From the end users perspective, the file download operation is seamless as they never leave the page on which the request originates.
Below is a simple contrived example of an ajax call to achieve this:
$.ajax({
type: 'POST',
url: '/Reports/ExportMyData',
data: '{ "dataprop1": "test", "dataprop2" : "test2" }',
contentType: 'application/json; charset=utf-8',
dataType: 'json',
success: function (returnValue) {
window.location = '/Reports/Download?file=' + returnValue;
}
});
url parameter is the Controller/Action method where your code will create the Excel file.
data parameter contains the json data that would be extracted from the form.
returnValue would be the file name of your newly created Excel file.
The window.location command redirects to the Controller/Action method that actually returns your file for download.
A sample controller method for the Download action would be:
[HttpGet]
public virtual ActionResult Download(string file)
{
string fullPath = Path.Combine(Server.MapPath("~/MyFiles"), file);
return File(fullPath, "application/vnd.ms-excel", file);
}
My 2 cents - you don't need to store the excel as a physical file on the server - instead, store it in the (Session) Cache. Use a uniquely generated name for your Cache variable (that stores that excel file) - this will be the return of your (initial) ajax call. This way you don't have to deal with file access issues, managing (deleting) the files when not needed, etc. and, having the file in the Cache, is faster to retrieve it.
I was recently able to accomplish this in MVC (although there was no need to use AJAX) without creating a physical file and thought I'd share my code:
Super simple JavaScript function (datatables.net button click triggers this):
function getWinnersExcel(drawingId) {
window.location = "/drawing/drawingwinnersexcel?drawingid=" + drawingId;
}
C# Controller code:
public FileResult DrawingWinnersExcel(int drawingId)
{
MemoryStream stream = new MemoryStream(); // cleaned up automatically by MVC
List<DrawingWinner> winnerList = DrawingDataAccess.GetWinners(drawingId); // simple entity framework-based data retrieval
ExportHelper.GetWinnersAsExcelMemoryStream(stream, winnerList, drawingId);
string suggestedFilename = string.Format("Drawing_{0}_Winners.xlsx", drawingId);
return File(stream, "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet.main+xml", suggestedFilename);
}
In the ExportHelper class I do use a 3rd party tool (GemBox.Spreadsheet) to generate the Excel file and it has a Save to Stream option. That being said, there are a number of ways to create Excel files that can easily be written to a memory stream.
public static class ExportHelper
{
internal static void GetWinnersAsExcelMemoryStream(MemoryStream stream, List<DrawingWinner> winnerList, int drawingId)
{
ExcelFile ef = new ExcelFile();
// lots of excel worksheet building/formatting code here ...
ef.SaveXlsx(stream);
stream.Position = 0; // reset for future read
}
}
In IE, Chrome, and Firefox, the browser prompts to download the file and no actual navigation occurs.
First Create the controller action that will create the Excel File
[HttpPost]
public JsonResult ExportExcel()
{
DataTable dt = DataService.GetData();
var fileName = "Excel_" + DateTime.Now.ToString("yyyyMMddHHmm") + ".xls";
//save the file to server temp folder
string fullPath = Path.Combine(Server.MapPath("~/temp"), fileName);
using (var exportData = new MemoryStream())
{
//I don't show the detail how to create the Excel, this is not the point of this article,
//I just use the NPOI for Excel handler
Utility.WriteDataTableToExcel(dt, ".xls", exportData);
FileStream file = new FileStream(fullPath, FileMode.Create, FileAccess.Write);
exportData.WriteTo(file);
file.Close();
}
var errorMessage = "you can return the errors in here!";
//return the Excel file name
return Json(new { fileName = fileName, errorMessage = "" });
}
then create the Download action
[HttpGet]
[DeleteFileAttribute] //Action Filter, it will auto delete the file after download,
//I will explain it later
public ActionResult Download(string file)
{
//get the temp folder and file path in server
string fullPath = Path.Combine(Server.MapPath("~/temp"), file);
//return the file for download, this is an Excel
//so I set the file content type to "application/vnd.ms-excel"
return File(fullPath, "application/vnd.ms-excel", file);
}
if you want to delete the file after downloaded create this
public class DeleteFileAttribute : ActionFilterAttribute
{
public override void OnResultExecuted(ResultExecutedContext filterContext)
{
filterContext.HttpContext.Response.Flush();
//convert the current filter context to file and get the file path
string filePath = (filterContext.Result as FilePathResult).FileName;
//delete the file after download
System.IO.File.Delete(filePath);
}
}
and finally ajax call from you MVC Razor view
//I use blockUI for loading...
$.blockUI({ message: '<h3>Please wait a moment...</h3>' });
$.ajax({
type: "POST",
url: '#Url.Action("ExportExcel","YourController")', //call your controller and action
contentType: "application/json; charset=utf-8",
dataType: "json",
}).done(function (data) {
//console.log(data.result);
$.unblockUI();
//get the file name for download
if (data.fileName != "") {
//use window.location.href for redirect to download action for download the file
window.location.href = "#Url.RouteUrl(new
{ Controller = "YourController", Action = "Download"})/?file=" + data.fileName;
}
});
I used the solution posted by CSL but I would recommend you dont store the file data in Session during the whole session. By using TempData the file data is automatically removed after the next request (which is the GET request for the file). You could also manage removal of the file data in Session in download action.
Session could consume much memory/space depending on SessionState storage and how many files are exported during the session and if you have many users.
I've updated the serer side code from CSL to use TempData instead.
public ActionResult PostReportPartial(ReportVM model){
// Validate the Model is correct and contains valid data
// Generate your report output based on the model parameters
// This can be an Excel, PDF, Word file - whatever you need.
// As an example lets assume we've generated an EPPlus ExcelPackage
ExcelPackage workbook = new ExcelPackage();
// Do something to populate your workbook
// Generate a new unique identifier against which the file can be stored
string handle = Guid.NewGuid().ToString()
using(MemoryStream memoryStream = new MemoryStream()){
workbook.SaveAs(memoryStream);
memoryStream.Position = 0;
TempData[handle] = memoryStream.ToArray();
}
// Note we are returning a filename as well as the handle
return new JsonResult() {
Data = new { FileGuid = handle, FileName = "TestReportOutput.xlsx" }
};
}
[HttpGet]
public virtual ActionResult Download(string fileGuid, string fileName)
{
if(TempData[fileGuid] != null){
byte[] data = TempData[fileGuid] as byte[];
return File(data, "application/vnd.ms-excel", fileName);
}
else{
// Problem - Log the error, generate a blank file,
// redirect to another controller action - whatever fits with your application
return new EmptyResult();
}
}
using ClosedXML.Excel;
public ActionResult Downloadexcel()
{
var Emplist = JsonConvert.SerializeObject(dbcontext.Employees.ToList());
DataTable dt11 = (DataTable)JsonConvert.DeserializeObject(Emplist, (typeof(DataTable)));
dt11.TableName = "Emptbl";
FileContentResult robj;
using (XLWorkbook wb = new XLWorkbook())
{
wb.Worksheets.Add(dt11);
using (MemoryStream stream = new MemoryStream())
{
wb.SaveAs(stream);
var bytesdata = File(stream.ToArray(), "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet", "myFileName.xlsx");
robj = bytesdata;
}
}
return Json(robj, JsonRequestBehavior.AllowGet);
}
$.ajax({
type: "GET",
url: "/Home/Downloadexcel/",
contentType: "application/json; charset=utf-8",
data: null,
success: function (Rdata) {
debugger;
var bytes = new Uint8Array(Rdata.FileContents);
var blob = new Blob([bytes], { type: "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet" });
var link = document.createElement('a');
link.href = window.URL.createObjectURL(blob);
link.download = "myFileName.xlsx";
link.click();
},
error: function (err) {
}
});
The accepted answer didn't quite work for me as I got a 502 Bad Gateway result from the ajax call even though everything seemed to be returning fine from the controller.
Perhaps I was hitting a limit with TempData - not sure, but I found that if I used IMemoryCache instead of TempData, it worked fine, so here is my adapted version of the code in the accepted answer:
public ActionResult PostReportPartial(ReportVM model){
// Validate the Model is correct and contains valid data
// Generate your report output based on the model parameters
// This can be an Excel, PDF, Word file - whatever you need.
// As an example lets assume we've generated an EPPlus ExcelPackage
ExcelPackage workbook = new ExcelPackage();
// Do something to populate your workbook
// Generate a new unique identifier against which the file can be stored
string handle = Guid.NewGuid().ToString();
using(MemoryStream memoryStream = new MemoryStream()){
workbook.SaveAs(memoryStream);
memoryStream.Position = 0;
//TempData[handle] = memoryStream.ToArray();
//This is an equivalent to tempdata, but requires manual cleanup
_cache.Set(handle, memoryStream.ToArray(),
new MemoryCacheEntryOptions().SetSlidingExpiration(TimeSpan.FromMinutes(10)));
//(I'd recommend you revise the expiration specifics to suit your application)
}
// Note we are returning a filename as well as the handle
return new JsonResult() {
Data = new { FileGuid = handle, FileName = "TestReportOutput.xlsx" }
};
}
AJAX call remains as with the accepted answer (I made no changes):
$ajax({
cache: false,
url: '/Report/PostReportPartial',
data: _form.serialize(),
success: function (data){
var response = JSON.parse(data);
window.location = '/Report/Download?fileGuid=' + response.FileGuid
+ '&filename=' + response.FileName;
}
})
The controller action to handle the downloading of the file:
[HttpGet]
public virtual ActionResult Download(string fileGuid, string fileName)
{
if (_cache.Get<byte[]>(fileGuid) != null)
{
byte[] data = _cache.Get<byte[]>(fileGuid);
_cache.Remove(fileGuid); //cleanup here as we don't need it in cache anymore
return File(data, "application/vnd.ms-excel", fileName);
}
else
{
// Something has gone wrong...
return View("Error"); // or whatever/wherever you want to return the user
}
}
...
Now there is some extra code for setting up MemoryCache...
In order to use "_cache" I injected in the constructor for the controller like so:
using Microsoft.Extensions.Caching.Memory;
namespace MySolution.Project.Controllers
{
public class MyController : Controller
{
private readonly IMemoryCache _cache;
public LogController(IMemoryCache cache)
{
_cache = cache;
}
//rest of controller code here
}
}
And make sure you have the following in ConfigureServices in Startup.cs:
services.AddDistributedMemoryCache();
$.ajax({
global: false,
url: SitePath + "/User/ExportTeamMembersInExcel",
"data": { 'UserName': UserName, 'RoleId': RoleId, UserIds: AppraseeId },
"type": "POST",
"dataType": "JSON",
"success": function (result) {
var bytes = new Uint8Array(result.FileContents);
var blob = new Blob([bytes], { type: "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet" });
var link = document.createElement('a');
link.href = window.URL.createObjectURL(blob);
link.download = "myFileName.xlsx";
link.click();
},
"error": function () {
alert("error");
}
})
[HttpPost]
public JsonResult ExportTeamMembersInExcel(string UserName, long? RoleId, string[] UserIds)
{
MemoryStream stream = new MemoryStream();
FileContentResult robj;
DataTable data = objuserservice.ExportTeamToExcel(UserName, RoleId, UserIds);
using (XLWorkbook wb = new XLWorkbook())
{
wb.Worksheets.Add(data, "TeamMembers");
using (stream)
{
wb.SaveAs(stream);
}
}
robj = File(stream.ToArray(), System.Net.Mime.MediaTypeNames.Application.Octet, "TeamMembers.xlsx");
return Json(robj, JsonRequestBehavior.AllowGet);
}
I may sound quite naive, and may attract quite a criticism, but here's how I did it,
(It doesn't involve ajax for export, but it doesn't do a full postback either )
Thanks for this post and this answer.
Create a simple controller
public class HomeController : Controller
{
/* A demo action
public ActionResult Index()
{
return View(model);
}
*/
[HttpPost]
public FileResult ExportData()
{
/* An example filter
var filter = TempData["filterKeys"] as MyFilter;
TempData.Keep(); */
var someList = db.GetDataFromDb(/*filter*/) // filter as an example
/*May be here's the trick, I'm setting my filter in TempData["filterKeys"]
in an action,(GetFilteredPartial() illustrated below) when 'searching' for the data,
so do not really need ajax here..to pass my filters.. */
//Some utility to convert list to Datatable
var dt = Utility.ConvertToDataTable(someList);
// I am using EPPlus nuget package
using (ExcelPackage pck = new ExcelPackage())
{
ExcelWorksheet ws = pck.Workbook.Worksheets.Add("Sheet1");
ws.Cells["A1"].LoadFromDataTable(dt, true);
using (var memoryStream = new MemoryStream())
{
pck.SaveAs(memoryStream);
return File(memoryStream.ToArray(),
"application/vnd.openxmlformats-officedocument.spreadsheetml.sheet",
"ExportFileName.xlsx");
}
}
}
//This is just a supporting example to illustrate setting up filters ..
/* [HttpPost]
public PartialViewResult GetFilteredPartial(MyFilter filter)
{
TempData["filterKeys"] = filter;
var filteredData = db.GetConcernedData(filter);
var model = new MainViewModel();
model.PartialViewModel = filteredData;
return PartialView("_SomePartialView", model);
} */
}
And here are the Views..
/*Commenting out the View code, in order to focus on the imp. code
#model Models.MainViewModel
#{Layout...}
Some code for, say, a partial View
<div id="tblSampleBody">
#Html.Partial("_SomePartialView", Model.PartialViewModel)
</div>
*/
//The actual part.. Just **posting** this bit of data from the complete View...
//Here, you are not posting the full Form..or the complete View
#using (Html.BeginForm("ExportData", "Home", FormMethod.Post))
{
<input type="submit" value="Export Data" />
}
//...
//</div>
/*And you may require to pass search/filter values.. as said in the accepted answer..
That can be done while 'searching' the data.. and not while
we need an export..for instance:-
<script>
var filterData = {
SkipCount: someValue,
TakeCount: 20,
UserName: $("#UserName").val(),
DepartmentId: $("#DepartmentId").val(),
}
function GetFilteredData() {
$("#loader").show();
filterData.SkipCount = 0;
$.ajax({
url: '#Url.Action("GetFilteredPartial","Home")',
type: 'POST',
dataType: "html",
data: filterData,
success: function (dataHTML) {
if ((dataHTML === null) || (dataHTML == "")) {
$("#tblSampleBody").html('<tr><td>No Data Returned</td></tr>');
$("#loader").hide();
} else {
$("#tblSampleBody").html(dataHTML);
$("#loader").hide();
}
}
});
}
</script>*/
The whole point of the trick seems that, we are posting a form (a part of the Razor View ) upon which we are calling an Action method, which returns: a FileResult, and this FileResult returns the Excel File..
And for posting the filter values, as said, ( and if you require to), I am making a post request to another action, as has been attempted to describe..
This thread helped me create my own solution that I will share here. I was using a GET ajax request at first without issues but it got to a point where the request URL length was exceeded so I had to swith to a POST.
The javascript uses JQuery file download plugin and consists of 2 succeeding calls. One POST (To send params) and one GET to retreive the file.
function download(result) {
$.fileDownload(uri + "?guid=" + result,
{
successCallback: onSuccess.bind(this),
failCallback: onFail.bind(this)
});
}
var uri = BASE_EXPORT_METADATA_URL;
var data = createExportationData.call(this);
$.ajax({
url: uri,
type: 'POST',
contentType: 'application/json',
data: JSON.stringify(data),
success: download.bind(this),
fail: onFail.bind(this)
});
Server side
[HttpPost]
public string MassExportDocuments(MassExportDocumentsInput input)
{
// Save query for file download use
var guid = Guid.NewGuid();
HttpContext.Current.Cache.Insert(guid.ToString(), input, null, DateTime.Now.AddMinutes(5), Cache.NoSlidingExpiration);
return guid.ToString();
}
[HttpGet]
public async Task<HttpResponseMessage> MassExportDocuments([FromUri] Guid guid)
{
//Get params from cache, generate and return
var model = (MassExportDocumentsInput)HttpContext.Current.Cache[guid.ToString()];
..... // Document generation
// to determine when file is downloaded
HttpContext.Current
.Response
.SetCookie(new HttpCookie("fileDownload", "true") { Path = "/" });
return FileResult(memoryStream, "documents.zip", "application/zip");
}
CSL's answer was implemented in a project I'm working on but the problem I incurred was scaling out on Azure broke our file downloads. Instead, I was able to do this with one AJAX call:
SERVER
[HttpPost]
public FileResult DownloadInvoice(int id1, int id2)
{
//necessary to get the filename in the success of the ajax callback
HttpContext.Response.Headers.Add("Access-Control-Expose-Headers", "Content-Disposition");
byte[] fileBytes = _service.GetInvoice(id1, id2);
string fileName = "Invoice.xlsx";
return File(fileBytes, System.Net.Mime.MediaTypeNames.Application.Octet, fileName);
}
CLIENT
(modified version of Handle file download from ajax post)
$("#downloadInvoice").on("click", function() {
$("#loaderInvoice").removeClass("d-none");
var xhr = new XMLHttpRequest();
var params = [];
xhr.open('POST', "#Html.Raw(Url.Action("DownloadInvoice", "Controller", new { id1 = Model.Id1, id2 = Model.Id2 }))", true);
xhr.responseType = 'arraybuffer';
xhr.onload = function () {
if (this.status === 200) {
var filename = "";
var disposition = xhr.getResponseHeader('Content-Disposition');
if (disposition && disposition.indexOf('attachment') !== -1) {
var filenameRegex = /filename[^;=\n]*=((['"]).*?\2|[^;\n]*)/;
var matches = filenameRegex.exec(disposition);
if (matches != null && matches[1]) filename = matches[1].replace(/['"]/g, '');
}
var type = xhr.getResponseHeader('Content-Type');
var blob = typeof File === 'function'
? new File([this.response], filename, { type: type })
: new Blob([this.response], { type: type });
if (typeof window.navigator.msSaveBlob !== 'undefined') {
// IE workaround for "HTML7007: One or more blob URLs were revoked by closing the blob for which they were created. These URLs will no longer resolve as the data backing the URL has been freed."
window.navigator.msSaveBlob(blob, filename);
} else {
var URL = window.URL || window.webkitURL;
var downloadUrl = URL.createObjectURL(blob);
if (filename) {
// use HTML5 a[download] attribute to specify filename
var a = document.createElement("a");
// safari doesn't support this yet
if (typeof a.download === 'undefined') {
window.location = downloadUrl;
} else {
a.href = downloadUrl;
a.download = filename;
document.body.appendChild(a);
a.click();
}
} else {
window.location = downloadUrl;
}
setTimeout(function() {
URL.revokeObjectURL(downloadUrl);
$("#loaderInvoice").addClass("d-none");
}, 100); // cleanup
}
}
};
xhr.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
xhr.send($.param(params));
});
This works for me. Make sure you return a File from your controller action with contentType as "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet" and file name as e.g. "List.xlsx" which should be the same as in the AJAX success call. I have used ClosedXML NuGet package to generate the excel file.
$.ajax({
url: "Home/Export",
type: 'GET',
contentType: 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
xhrFields: { responseType: 'blob' },
success: function (data) {
var a = document.createElement('a');
var url = window.URL.createObjectURL(data);
a.href = url;
a.download = 'List.xlsx';
a.click();
window.URL.revokeObjectURL(url);
}
});
I am using Asp.Net WebForm and just I wanna to download a file from server side. There is a lot article but I cannot find just basic answer.
Now, I tried a basic way and got it.
That's my problem.
I have to create a lot of input button dynamically on runtime. And I want to add each button to download button with giving an unique fileNumber.
I create each button like this:
fragment += "<div><input type=\"button\" value=\"Create Excel\" onclick=\"CreateExcelFile(" + fileNumber + ");\" /></div>";
Each button call this ajax method.
$.ajax({
type: 'POST',
url: 'index.aspx/CreateExcelFile',
data: jsonData,
contentType: 'application/json; charset=utf-8',
dataType: 'json',
success: function (returnValue) {
window.location = '/Reports/Downloads/' + returnValue.d;
}
});
Then I wrote a basic simple method.
[WebMethod]
public static string CreateExcelFile2(string fileNumber)
{
string filePath = string.Format(#"Form_{0}.xlsx", fileNumber);
return filePath;
}
I am generating this Form_1, Form_2, Form_3.... And I am going to delete this old files with another program. But if there is a way to just sending byte array to download file like using Response. I wanna to use it.
I hope this will be usefull for anyone.
On Submit form
public ActionResult ExportXls()
{
var filePath="";
CommonHelper.WriteXls(filePath, "Text.xls");
}
public static void WriteXls(string filePath, string targetFileName)
{
if (!String.IsNullOrEmpty(filePath))
{
HttpResponse response = HttpContext.Current.Response;
response.Clear();
response.Charset = "utf-8";
response.ContentType = "text/xls";
response.AddHeader("content-disposition", string.Format("attachment; filename={0}", targetFileName));
response.BinaryWrite(File.ReadAllBytes(filePath));
response.End();
}
}
I would like to provide a file download operation by using the jQuery AJAX call with some params under MVC
Example
(javascript)
function DoDownload(startDate) {
$.ajax({
url:"controller/GetFile/",
data: {startDate:startDate}
...
});
}
C# Controller Code
public void GetFile(string startDate) {
var results = doQueryWith(startDate);
// Create file based on results
....
// How do I tell the server to make this a file download??
}
I typically would just make my file download a link such as:
<a h r e f="mycontroller/getfile/1"/>Download</a>
but in the case above the date will be dynamic.
If I don't use ajax, what would be a preferred way to pass in the params to the MVC controller using javascript?
Example:
window.location = "mycontroller/GetFile/" + $("#fromDate").val();
assuming the date is 12-25-2012
Would this produce
mycontroller/GetFile/12/25/2012
would MVC treat this as three params?
What I ended up doing is calling my controller from my javascript like:
var url = "/mycontroller/GetFile?startDate=" + $("#mydate").val() + etc...
window.location = url;
mycontroller.cs
public void GetFile(DateTime startDate)
{
}
My original concern was with the date parameters. I didnt want to have to parse it.
Using the ActionLink helper, you can pass multiple params to your controller:
HtmlHelper.ActionLink(
string linkText,
string actionName,
string controllerName,
object routeValues,
object htmlAttributes
)
So in your case:
#Html.ActionLink("Download file", "GetFile", "MyController", new { startDate = "##" }, new { id="mydownloadlink" })
Using jQuery you can change the value of the startDate in the link with the content of your date picker or textbox.
$("#mydownloadlink").attr("href").replace("##", $("#yourdatetexbox").val);
Then, in your controller, just use one of the other answers here, about FileResult.
Hope this help you...
You can use the File method of controller class to return a file back to the browser.
The below sample returns a pdf file.
public ActionResult GetFile(int id)
{
var fileInfo=repositary.GetFileDedetails(id);
var byteArrayOFFile=fileInfo.FileContentAsByteArray();
return File(byteArrayOFFile,"application/pdf","yourFriendlyName.pdf");
}
Assuming repositary.GetFileDedetails method returns the details of the file from the id.
You may also return the file from a physical location(a path) or a stream. Check all the overloads of the File method and use appropriate one.
This has nothing to do with ajax. this is normal GET request over a browser.
Your controller action method should return a FileResult instead of void. And there is no need to do this via AJAX - in fact, you don't want to do this with AJAX. You'll need the browser involved so it knows to provide a download dialog for the user.
See these links:
Handling an ASP.NET MVC FileResult returned in an (jQuery) Ajax call
File download in Asp.Net MVC 2
I hope this helps.
This works for me. Make sure you return a File from your controller action with contentType as "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet" and file name as e.g. "List.xlsx" which should be the same as in the AJAX success call. I have used ClosedXML NuGet package to generate the excel file.
public IActionResult GetFile(DateTime startDate)
{
var results = doQueryWith(startDate);
DataTable dt = new DataTable("Grid");
//populate dt here.
//if you result is a data table you can assign it to dt
dt = results;
string contentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
string fileName = "List.xlsx";
using (var workbook = new XLWorkbook())
{
workbook.Worksheets.Add(dt);
using (var stream = new MemoryStream())
{
workbook.SaveAs(stream);
workbook.SaveAs(stream);
var content = stream.ToArray();
return File(content, contentType, fileName);
}
}
}
//.cshtml (JQuery AJAX call to the controller action)
$.ajax({
url:"ControllerName/GetFile/",
data: {startDate:startDate}
contentType: 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet',
xhrFields: { responseType: 'blob' },
success: function (data) {
var a = document.createElement('a');
var url = window.URL.createObjectURL(data);
a.href = url;
a.download = 'List.xlsx';
a.click();
window.URL.revokeObjectURL(url);
}
});
This is with ASP.NET Web Forms .NET 2.0 -
I have a situation that I am not sure how to fulfill all the requirements. I need to update an img source on the page if selections are made from a drop down on the same page.
Basically, the drop downs are 'options' for the item. If a selection is made (i.e. color: red) then I would update the img for the product to something like (productID_red.jpeg) IF one exists.
The problem is I don't want to do post backs and refresh the page every time a selection is made - especially if I do a check to see if the image exists before I swap out the img src for that product and the file doesn't exist so I just refreshed the entire page for nothing.
QUESTION:
So I have easily thrown some javascript together that formulates a string of the image file name based on the options selected. My question is, what options do I have to do the following:
submit the constructed image name (i.e. productID_red_large.jpg) to some where that will verify the file exists either in C# or if it is even possible in the javascript. I also have to check for different possible file types (i.e. .png, .jpg...etc.).
not do a post back and refresh the entire page
Any suggestions?
submit the constructed image name
(i.e. productID_red_large.jpg) to some
where that will verify the file exists
either in C# or if it is even possible
in the javascript. I also have to
check for different possible file
types (i.e. .png, .jpg...etc.).
not do a post back and refresh the
entire page
If you wish to not post back to the page you will want to look at $.ajax() or $.post() (which is just short hand for $.ajax() with some default options)
To handle that request you could use a Generic Http Handler.
A simple outline could work like the following:
jQuery example for the post:
$("someButton").click(function () {
//Get the image name
var imageToCheck = $("#imgFileName").val();
//construct the data to send to the handler
var dataToSend = {
fileName: imageToCheck
};
$.post("/somePath/ValidateImage.ashx", dataToSend, function (data) {
if (data === "valid") {
//Do something
} else {
//Handle error
}
}, "html");
})
Then on your asp.net side you would create an http handler that will validate that request.
public class Handler1 : IHttpHandler
{
public void ProcessRequest(HttpContext context)
{
var fileName = context.Request["fileName"];
var fullPath = Path.Combine("SomeLocalPath", fileName);
//Do something to validate the file
if (File.Exists(fullPath))
{
context.Response.Write("valid");
}
else
{
context.Response.Write("invalid");
}
}
public bool IsReusable
{
get
{
return false;
}
}
}
Hope this helps, if I missed the mark at all on this let me know and I can revise.
We have an app of the same type, webforms .net 2, we do something similar with the following setup:
Using jQuery you can call a method in the page behind of the current page, for example, the following will trigger the AJAX call when the select box called selectBoxName changes, so your code work out the image name here and send it to the server.
$(document).ready(function () {
$('#selectBoxName').change(function (event) {
var image_name = 'calculated image name';
$.ajax({
type: "POST",
url: 'SomePage.aspx/CheckImageName',
data: "{'imageName': '" + image_name + "'}",
contentType: "application/json; charset=utf-8",
dataType: "json",
success: function (msg) {
alert(msg);
},
error: function (a, b, c) {
alert("The image could not be loaded.");
}
});
});
});
Where SomePage.aspx is the current page name, and image_name is filled with the name you have already worked out. You could replace the img src in the success and error messages, again using jQuery.
The code behind for that page would then have a method like the following, were you could just reutrn true/fase or the correct image path as a string if needed. You can even return more complex types/objects and it will automatically send back the proper JSON resposne.
[System.Web.Services.WebMethod(true)]
[System.Web.Script.Services.ScriptMethod(ResponseFormat = System.Web.Script.Services.ResponseFormat.Json)]
public static bool CheckImageName(string imageName)
{
/*
* Do some logic to check the file
if (file exists)
return true;
return false;
*/
}
As it is .net 2 app, you may need to install the AJAX Extensions:
http://www.microsoft.com/downloads/en/details.aspx?FamilyID=ca9d90fa-e8c9-42e3-aa19-08e2c027f5d6&displaylang=en
Could you not use a normal ajax call to the physical path of the image and check if it returns a 404?
Like this:
http://stackoverflow.com/questions/333634/http-head-request-in-javascript-ajax
<script type="text/javascript">
function UrlExists(url) {
var http = new XMLHttpRequest();
http.open('HEAD', url, false);
http.send();
return http.status != 404;
}
function ConstructImage() {
var e = document.getElementById("opt");
var url = '[yourpath]/' + e.value + '.jpg';
if (!UrlExists(url)) {
alert('doesnt exists');
//do stuff if doesnt exist
} else {
alert('exists');
//change img if it does
}
}
</script>
<select id="opt" onchange="ConstructImage()">
<option value="red">Red</option>
<option value="blue">Blue</option>
<option value="green">Green</option>
</select>