Syscomments...

Empty Data Regions

When the dataset for a data region returns no data, the data region is not rendered. Instead, a text box is rendered that displays the value of the NoRows property. You can edit the NoRows property in the Property window of Report Designer. The appearance properties for the data region (for example, Color, Font, and Padding) apply to the NoRows text box. 

 I thought of concatenating all the column names and use the NoRows property but that will be exported as 1 column rather than individual columns. I found a couple of hacks for this. Thought it could be useful for someone else...

(1) I can put the columns in the Page header ( Since I can't put table in the header I can throw in some textboxes) with the same width as the column below in the body section. This is a feasible solution.

(2) Modify the stored proc to something like :  

SELECT    col1, col2...
FROM    <table>

UNION ALL

SELECT  NULL,  NULL

This will return a blank row at the end of the report and RS treats this as a row. So when exported we do get a row with headers and a blank row.

(3) This is not very efficient but it works...

Get the results of the stored proc into a temp table. If there are no rows in the temp table then do a UNION with nulls (like in (2) above) and return the result set else do a SELECT * FROM temptable. This can affect the performance coz it uses temp tables...but for cases where the Report design cannot be modified and the stored proc cannot be modified ..this could be handy.