I have an application that is written in VB.Net 2005 that accesses Excel 2003. Basically, I'm trying to open an Excel template and read in data from the template's charts and sheets. I can read the sheets fine but I'm having trouble with the charts.

Because this is a template, the charts have series that are defined but there is no data. I'm trying to determine the range for each of the series in a chart using the seriescollection object. This will not work with a template but works fine if I save the template to an xls and read the data from the xls.

I guess that my question is what is the difference in formatting between an xlt and xls?

Howdy. Interesting. I have a rather complex .xlt that I just updated yesterday, and did not notice any difference in the formatting between it and .xls that it was originally based on. However, I didn't use VBA/VB.net. Also, my data tables had dummy data in them - I supply this to about 20 others who use this framework. Not sure if that makes a difference.

Yeah, everything looks normal if I open the template with Excel. The problem comes about when I try to progamatically obtain the data range for a chart series.

I found the problem. You can't obtain the series data from either an xlt or xls file if there is no data associated with the series. I had to add a row of zeros, gather my data the delete the zeros.