Getting Started

So how do I start?

In most cases you probably have some data that you want to move to an Excel spreadsheet, do some styling, maybe add a formula or a chart.

But before we get started, here's something to keep in mind when you work with EPPlus:
Cell addresses, number formats and formulas are culture-insensitive, meaning things might look a little bit different when you write your code. This is the way OOXML is stored and is then translated too your culture when the workbook is opened in Excel.

Addresses are separated by a comma (,).
Example worksheet.Cells["A1:C1,C3"].Style.Font.Bold = true.

Numberformats use dot for decimal (.) and comma (,) for thousand separator.
Example worksheet.Cells["B2:B3"].Style.NumberFormat.Format = "#,##0.00";.

Formulas use comma (,) to separate parameters.
Example worksheet.Cells["C11"].Formula="SUBTOTAL(9,\"C1:C10\")";.

ExcelPackage

The first thing you do is to create an instance to the ExcelPackage class. To do that you first need to add a using directive to OfficeOpenXml namespace in the top of your file. This is the top namespace in EPPlus;

using OfficeOpenXml;

You can now reference the Excelpackage class directly for your class. The ExcelPackage class has few different constructors depending on what you want to do...

        //Creates a blank workbook. Use the using statment, so the package is disposed when we are done.
	using (var p = new ExcelPackage())
        {
           //A workbook must have at least on cell, so lets add one... 
           var ws=p.Workbook.Worksheets.Add("MySheet");
           //To set values in the spreadsheet use the Cells indexer.
           ws.Cells["A1"].Value = "This is cell A1";
           //Save the new workbook. We haven't specified the filename so use the Save as method.
           p.SaveAs(new FileInfo(@"c:\workbooks\myworkbook.xlsx"));
        }

You can also specify a workbook directly in the constructor.

        //Open the workbook (or create it if it doesn't exist)
        var fi=new FileInfo(@"c:\workbooks\myworkbook.xlsx")
	using (var p = new ExcelPackage(fi))
        {
           //Get the Worksheet created in the previous codesample. 
           var ws=p.Workbook.Worksheets["MySheet"];
           Set the cell value using row and column.
           ws.Cells[2, 1].Value = "This is cell A2. It is set to bolds";
           //The style object is used to access most cells formatting and styles.
           ws.Cells[2, 1].Style.Font.Bold=true;
           //Save and close the package.
           p.Save();
        }

EPPlus can also work with workbooks as streams. This can be useful when reading files from a web server or you want to pass workbooks without having a physical file. You can also pass a password to the constructor, if the workbook is encrypted.