I'm trying to create a 2007+ Excel document (.xlsx), using nothing but VB.net and .net4.0 built-in classes. So I can't use any third party libraries, including Open XML SDK. The code already works fine for basic workbooks, multiple sheets, styles, etc. The resulting files open fine in Excel and calc etc.
Now I am trying to add pivotTables. They are a bit weird, as they are spread out in multiple files. I have created the Cache and Table in their proper "folders", added the pointer from workbook to the cache and the various related _rels entries... everything seems OK but Excel always reports "... found unreadable content in..."
The only obvious issue I can see is that the content_types.xml file in the resulting Package does not have an Override for the pivotTable. It does have one for the Cache, which I do not do in code, so I'm assuming Packaging has noticed the Cache and added a line here. I'm not clear on why the pivotTable didn't show up.
So looking for experts in Packaging that might point me in the right direction: is a missing line in content_types fatal to opening the file, and if so, how can I force the pivotTable to appear?
