How to access worksheets in EPPlus?

Question

I'm using the 3.1 release of EPPlus library to try to access a worksheet in an Excel file. When I try either of the following methods I get a System.ArgumentException : An item with the same key has already been added.

using (ExcelPackage package = new ExcelPackage(new FileInfo(sourceFilePath)))
{
   var worksheet = package.Workbook.Worksheets[0];

   // OR

   foreach (var excelWorksheet in package.Workbook.Worksheets)
   ...
}

Exception Stack:

System.ArgumentException : An item with the same key has already been added.
   at System.ThrowHelper.ThrowArgumentException(ExceptionResource resource)
   at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)
   at System.Collections.Generic.Dictionary`2.Add(TKey key, TValue value)
   at OfficeOpenXml.ExcelNamedRangeCollection.Add(String Name, ExcelRangeBase Range)
   at OfficeOpenXml.ExcelWorkbook.GetDefinedNames()
   at OfficeOpenXml.ExcelPackage.get_Workbook()

This seems like very basic functionality to have be so broken.. am I doing something wrong?

Answer 1

The workbook in question had named ranges defined. These were causing problems so I created a new xlsx file with just the data I needed and it was able to open fine.