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export to XLSB using epplus asp.net c#

In my project there is a specific page that exports a lot of data (around 1 million rows and 30 columns) in an excel "XLSX" file. But the file size is big, so it is taking a lot to download the file. However when I manually saved the file as "XLSB" (binary format) then it significantly reduced the file size.
The coding part to create and download xlsx file is working fine. I am using the following code to do this:
DataTable dtDump = GetData();
workSheet_dump.Cells["A1"].LoadFromDataTable(dtDump, true);
using (var memoryStream = new MemoryStream())
{
Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
Response.AddHeader("content-disposition", "attachment; filename=DumpReport.xlsx");
excel.SaveAs(memoryStream);
memoryStream.WriteTo(Response.OutputStream);
Response.Flush();
Response.End();
}
Is there any way in epplus, or any alternative way by which I can export the data in "XLSB" format?

Convert asp:Table to excel format

I am able to to generate excel file from asp:table,but after generating excel file while opening file it gives warning .file you are trying to open is in a different format than specified by the file extension I have found solution to this warning from this link http://www.aspsnippets.com/Articles/Solution-ASPNet-GridView-Export-to-Excel-The-file-you-are-trying-to-open-is-in-a-different-format-than-specified-by-the-file-extension.aspx
so i have used ClosedXML Library but while adding data to excel sheet it's accepting datable,dataset format only and i got data in string format so it's generating blank excel sheet. please check code i have tried.
LoadDetailsToTable();
System.IO.StringWriter sw = new System.IO.StringWriter();
System.Web.UI.HtmlTextWriter hw = new HtmlTextWriter(sw);
tbl_loctbl.RenderControl(hw);
using (XLWorkbook wb = new XLWorkbook())
{
var ws = wb.Worksheets.Add("asd");
ws.Cell(2, 1).InsertTable(sw.ToString());
HttpContext.Current.Response.Clear();
HttpContext.Current.Response.ContentType = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet";
HttpContext.Current.Response.AddHeader("content-disposition", String.Format(#"attachment;filename=newfile.xlsx"));
using (MemoryStream MyMemoryStream = new MemoryStream())
{
wb.SaveAs(MyMemoryStream);
MyMemoryStream.WriteTo(HttpContext.Current.Response.OutputStream);
MyMemoryStream.Close();
}
HttpContext.Current.Response.End();
}
Here LoadDetailsToTable() function load data to asp table.tbl_loctbl is table id.

Unfortunately the two markups you're using are incompatible. HTML table markup in Excel is supported, but its not in OpenXML which is what your library is expecting to output.
Under the hood, Excel is expecting a valid XML file format; html, while loosely supported, isn't the native xlsx format.
There are libraries available that will convert html to openxml on the internet, however this can be solved by iterating over your dataset and actually adding cells and rows using the OpenXML SDK

Export to excel opening it

I currently have an option in my app to export to Excel. It saves the data to a file in disk.
I would like to open Excel instead and show the data. Do any of you know if this is possible and how to accomplish it?
I guess I can just open the file I'm already saving to disk, but it would be just better to not save a file to disk at all.

I am assuming you are using Interop. Just set the Application to Visible.
excelApp.Visible = true;
where
InteropExcel.Application excelApp;
Just remember to still release all the COM references so that your application does not also hold a handle to Excel. That may cause your Excel file to be read-only.

How are you currently creating your file?
If you are using the Excel engine or POI (or what ever thier abbreviation is) to create an XLS / XLSX it would just be a case of not saving the workbook and making the instance visible (as per above)?
If you are not dependant on or do not want to be dependant on Excel (i.e. using 3rd party libraries like Syncfusion to create the file) or just outputting your data in an excel readable format like CSV, then I guess you're stuck with a file-based operation...
As for a temp file being easier than an unsaved one... the data needs to be created in either instance, either simple CSV or a coded population of Excel cells, so I don't quite see what is meant by that.

Refer Below code to open excel without saving
System.Web.HttpContext.Current.Response.Clear();
System.Web.HttpContext.Current.Response.AddHeader("content-disposition", "attachment; filename=DateTime.Now + ".xls");
System.Web.HttpContext.Current.Response.Charset = "";
Response.Cache.SetCacheability(HttpCacheability.NoCache); // If you want the option to open the Excel file without saving than
System.Web.HttpContext.Current.Response.ContentType = "application/vnd.xls";
System.IO.StringWriter stringWrite = new System.IO.StringWriter();
System.Web.UI.HtmlTextWriter htmlWrite = new HtmlTextWriter(stringWrite);
Gridview1.RenderControl(htmlWrite);
//style to format numbers to string
string style = #"<style> .textmode { } </style>";
System.Web.HttpContext.Current.Response.Write(style);
System.Web.HttpContext.Current.Response.Output.Write(stringWrite.ToString());
System.Web.HttpContext.Current.Response.Flush();
System.Web.HttpContext.Current.Response.End();

How to make a real XLS file on asp.net c#?

I have this code to extract a table to computer in a .xls file:
// I have a string which contains HTML table codes, named as excelTable
HttpResponse response = HttpContext.Current.Response;
response.Clear();
response.AddHeader("Content-Disposition", String.Format("Attachment;Filename=file.xls", ));
response.Buffer = true;
response.ContentEncoding = System.Text.Encoding.Default;
response.ContentType = "application/vnd.ms-excel";
response.Write(excelTable);
response.End();
And I have seen that this is not a real .xls file. I can open it in Notepad and see my standart html table codes.
Now I understand that defining ContentType is not enough. So what else can I do to generate a pure .xls or .xlsx file? Or Should I certainly use Excel Libraries like OpenXML, Interop, etc. ?

Actual XLS/XLSX data must be sent back - that is, data generated with a library (e.g EEPlus) or other suitable source.
This common hack/approach works because Excel "knows how to read HTML". It doesn't actually turn the HTML into XSL/XLSX, although it can be saved as new spreadsheet once loaded by Excel.
Changing the content type will have no effect on the data, and instead will effectively stop this approach from working: the content type is used for associating the program (i.e. Excel) which will be used to open/read the data.
So yes: to generate a real XLS/XLSX document, use a library.

ASP.Net Export Data to Excel

Wondering what is a good library I can use with VS2005 to export data to a excel file. The file has some formatting like background colors and colspans.
Thanks

Here is some code that uses a trick to output HTML to an Excel file. I have found that you can trick excel into opening an HTML by setting the content type of the output to "application/excel".
In the code below secresults is an HTML div like so:
<div id="secresults" runat="server" visible="false" class="secresults">
Content or data here.
</div>
In code behind:
Response.ClearContent();
string filename = "Output" + istartDate.ToShortDateString() + ".xls";
Response.AddHeader("content-disposition", "attachment; filename=" + filename + ";");
Response.ContentType = "application/excel";
StringWriter sw = new StringWriter();
HtmlTextWriter htw = new HtmlTextWriter(sw);
secresults.RenderControl(htw);
Response.Write(sw.toString());
Response.End();
I have found that you can use some html formatting in excel. To test which formatting you can use you can create an html file and rename it to a .xls file, then open it with excel. You can get a pretty good idea about what HTML Excel will read.

I would recommend taking the class from the following website, and adapting it to your needs.
Mikes Knowledge Base - ExportToExcel
By default, this class takes a DataSet, DataTable or List<>, and exports it into a genuine Excel 2007 .xlsx file, using the OpenXML libraries (also provided).
It doesn't currently attempt to add any formating to the Excel cells (DataTables only store values, not formating, colors, horizontal alignment, etc !) but it should be a good place to start from.
All source code is provided, free of charge, so you can adapt it as required.
Good luck !

I have used this library in the past, but I normally just spit out a CSV file.
C# class library for exporting data to CSV/Excel file

If you have predefined layout of the document, Templater will probably fit your description.
Take a look at the example on how to use it.

I've used this codeplex project (Excel Package). One technique is to start with a formatted template, then modify the template. That is much easier than applying a lot of styling commands starting with an empty spreadsheet.