Download excel file in c# using openxml

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Viewed 5k times. How can I offer this Excel sheet to the user for download without saving it in any form locally? Create DateTime. AddWorkbookPart ; workbookpart. Save ; spreadsheetDocument. Row row; if sheetData. Determine where to insert the new cell.

Compare cell. OpenXml " nuget package. This is Microsoft's library for creating Excel files. And finally, you need to get your code to call the StreamExcelDocument function. I actually demonstrate how to do this from an ASP. How simple that that! You basically pass it a List , give it a filename, then my library creates the Excel file for you, and passes it back in a FileStreamResult object. If you're still using the original ASP. NET and if so, why?! Add each of these.

Using ASP. NET Core , you have access to three functions, for creating your Excel files. For example, if my ASP. The Excel class is responsible of all the operations done against the Excel spreadsheet.

It's kinda utility class, but note that it's nowhere near ready. It's supposed to be used as a learning tool or a seed to an actual implementation. One surprise was that the order of the elements in XML files is very important. For example elements in style sheet such as fonts, fills, borders, cellStyleXfs, cellXfs etc must be in specific order.

Otherwise the document is interpreted as corrupted. Another observation was that the indexes of the elements are quite often used for example the index of a shared string. However there is no support in the library to fetch the indexes so the collections have to be looped in order to calculate the index of a desired element. If you download the project, you'll notice that fully qualified class names are used.

In this article I have removed the namespaces before the classes in order to enhance readability. So if you are copying code from the code snippets, don't forget to define using in C or Imports in VB for the two namespaces:. Now to the code.

The first thing is to create the spreadsheet. This is actually the xlsx file. The spreadsheet is created in C as follows. After the spreadsheet document is created, four elemental parts common to all worksheets are added:. One way to create the style definitions is to create them from the code.

In the demo, the following basic styles are created:. Another thing is that, as mentioned before, the order of the style sheet elements is critical. If the order isn't correct, Excel will very easily interpret the document as corrupted. An excerpt from the style creation is the creation of CellStyleFormats element and a CellFormat element inside the formats:.

Another way to define the styles is to use an existing XML file that holds the style definition. In the project theres a PredefinedStyles. The contents of this file are read into a string which is then added to the empty stylesheet created previously. The style definitions look as following it's actually the same that is also created using the code :.

As a matter of fact basically any element can be filled by just adding an XML into it. For example a worksheet can be filled by adding a proper XML as the inner text of the worksheet. Next step is to add a worksheet. Adding a worksheet is straight-forward. However, one gotcha is to remember to define the relation to the workbook. Otherwise the sheet isn't included when the workbook is opened. Another thing is to remember to number the sheets correctly.

Because of this the amount of sheets is queried when defining the SheetId. A workbook contains a table of shared strings.