Update a table linked to a PowerPivot datamodel using EPPlus and it corrupts the datamodel - vb.net

Question

Using EPPlus I read an XLSX file.
I replace the data in a table and set the table range.
When I open the resulting spreadsheet I get an error:
"We found a problem with some content in 'MySpreadsheet.xlsx'. Do you want us to try to recover as much as we can?" -- I click Yes and I get another error:
"Excel was able to open the file by repairing or removing the unreadable content. Removed Part: Data store"
The error only happens after I add this table to a PowerPivot data model.
[EDIT] - I created a win forms app that reproduces this problem. You
can download it at here
I found the problem but don't know how
to fix it.
rename the xlsx to zip
Open the zip and browse to the xl\workbook.xml file
Look for the node collection.
Notice how EPPlus changes the <definedNames> collection to use absolute cell addresses.
Excel: <definedName name="_xlcn.LinkedTable_MyDate" hidden="1">MyDate[]</definedName>
EPPlus: <definedName name="_xlcn.LinkedTable_MyDate" hidden="1">'MyDate'!$A$2:$A$5</definedName>
If I modify this line after EPPlus is done saving then I can pull it
up in Excel without corrupting the Data Model.
I tried changing the WorkbookXml but it is happening when the
ExcelPackage.Save method runs.
For Each node In pck.Workbook.WorkbookXml.GetElementsByTagName("definedNames")(0).ChildNodes
node.innerText = "MyDate[]"
Next
Any ideas?
Try this first: create a spreadsheet with one table in it. Name the worksheet and table "DateList". Save it and run the below code on it -- it will work.
Then do this: open the same spreadsheet and add the DateList table to a pivottable data model. Save it and run the below code on it -- it will fail.
Here's some code from my MVC Controller -- only the relevant bits:
Public Class ScorecardProgressReportDatesVM
Public Property WeekRange As Date
End Class
Public Function GetScorecardProgressReport(id As Integer) As ActionResult
Dim contentType As String = "application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"
Dim DateList As New List(Of ScorecardProgressReportDatesVM)
DateList.Add(New ScorecardProgressReportDatesVM With {.WeekRange = CDate("Jan 1, 2015")})
DateList.Add(New ScorecardProgressReportDatesVM With {.WeekRange = CDate("Jan 1, 2015")})
Dim templateFile As New IO.FileInfo("c:\test.xlsx")
Dim ms As New IO.MemoryStream
Using pck As New ExcelPackage(templateFile)
ExtendTable(pck, "DateList", DateList)
pck.SaveAs(ms)
ms.Position = 0
End Using
Dim fsr = New FileStreamResult(ms, contentType)
fsr.FileDownloadName = "StipProgress.xlsx"
Return fsr
End Function
Private Sub ExtendTable(package As ExcelPackage, tableName As String, newList As Object)
Dim ws As OfficeOpenXml.ExcelWorksheet
ws = package.Workbook.Worksheets(tableName)
Dim OutRange = ws.Cells("A1").LoadFromCollection(newList, True)
Dim t = ws.Tables(tableName)
Dim te = t.TableXml.DocumentElement
Dim newRange = String.Format("{0}:{1}", t.Address.Start.Address, OutRange.End.Address)
te.Attributes("ref").Value = newRange
te("autoFilter").Attributes("ref").Value = newRange
End Sub

Answer 1

In order to fix this we had to change the EPPlus v4.04 source code.
ExcelWorkbook.cs # line 975 was changed
//elem.InnerText = name.FullAddressAbsolute; This was causing issues with power pivot
to
elem.InnerText = name.FullAddress; //Changed to full address... so far everything is working