c# embed resources problem on windows xp (NullReferenceException)

Question

Hi,

I'm using an embed resources in my c# application

string sPath = System.IO.Path.GetTempFileName();
System.IO.File.WriteAllBytes(sPath, Properties.Resources.test)
workbook = app.Workbooks.Open(sPath,missing, missing, missing, missing, missing, missing, missing, missing, missing, missing, missing, missing, missing, missing);

It worked fine until today,It throw me some bad exception:

System.NullReferenceException: Object reference not set to an instance of an object at ......

It is only on 2 windows xp proffesional edition installations, both root and user accounts (user account is very limited there, because of admin policy).

Till today it worked on several xp and vista installation, without any problems.

What could be a cause of this problem?

Thank you for any ideas.

Answer 1

I think this would be a reference issue due to version problem as you stated. Since you added in a reference to the Microsoft Excel 11.0 Object Library (2003 excel) then I don't think you can create an Microsoft Excel 9.0 (Excel 2000) app. I've never tried dealing with different versions but maybe you can add both reference in and open them in a try and catch when one fails.

pseudo code

try{
workbook = app.Workbooks.Open(sPath,missing, missing, missing, missing, missing, missing, missing, missing, missing, missing, missing, missing, missing, missing);
}
catch ( NullReferenceException e )
{
      // This means the user is in Excel 9.0 (Excel 2000)
      // Open workbook as Excel 2000
}

Hope this helps