Hi,
The approach illustrated in the thread that you have mentioned is applicable only for CSV export, as the CSV format does not apply any restrictions other that using a valid separation token. On the other hand html implies that a specific document structure should be followed. RadGridView's html export generates an html table (<table>) that arranges cells and their content (<td>) in the respective rows (<tr>). If the mentioned approach is follwed, you will have something like this:
This is not a valid document structure, so that Excel fails to render it. You have to wrap the inner table into "<tr><td colspan="?">...</td></tr> to make it work properly.
Regards,
Ivan Ivanov
Telerik
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