How to resolve Excel.Application.Workbooks.Open failing when called from WCF Service?

Hi:

I hope things are going well as you're getting ready for the Holiday Season.

I was wondering if you had a couple of minutes to read over a WCF issue I've been  working on trying to resolve.

I have a WCF service which utilizes XL Spreadsheets on the backend as part of it's calculation engine. I'm using a 3rd party  .Net based component called Aspose to access, manipulate and retrieve data from the spreadsheet.

Unfortunately, Aspose ran into a couple of calculation bugs. In in order to overcome these issues,  as a temporary fix, I save a temporary copy of the current spreadsheet. I then open the spreadsheet (which forces a recalc) with the Microsoft Excel .Net library - Microsoft.Office.Interop.Excel. Then I reopen that temp spreadsheet using Aspose to collect  the result values

This fix has worked fine as I've been implementing/debugging the solution locally.

When I deployed the service to IS 7.0, the MS .Net Excel library fails when attempting to open the file.

I think this some kind of permissions issue with the deployed IIS service.

This is a snippet of the code that is failing

String fullPath1 = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "App_Data", "BCBSDiabetesCalculator.xlsm");

// Open to force Excel to perform calculation itself
Microsoft.Office.Interop.Excel.Application excelApp1 = new Microsoft.Office.Interop.Excel.Application();

var excelWorkbook1 = excelApp1.Workbooks.Open(fullPath1);

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The following code block where I opening a filestream and passing it to the Aspose library call works.

//Get the Excel file into stream
FileStream stream = new FileStream(fileName, FileMode.Open);

//Instantiate LoadOptions specified by the LoadFormat.
LoadOptions loadOptions = new LoadOptions(LoadFormat.Xlsx);

//Create a Workbook object and opening the file from the stream
_workbook = new Workbook(stream, loadOptions);

if (_workbook == null)
{
}

// Make sure that we close the stream.
stream.Close();

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Do you have any insight/ideas on how to resolve this?


Thanks,
JohnB