I ran across a very frustrating problem today when working on a project for a client.  I was placing a GridView onto a page, into which went a number of fields, one of which is a dollar amount.  I did a quick search and discovered that the BoundColumn has a property called DataFormatString.  Sounds good, I say.  So into this field I put the old familiar “{0:c}”, only to discover that my grid was still showing numbers like “1.0000″ or “0.9900″.  After a lot of head scratching, some MSDN reading, and a lot of Googling, I finally found the answer…

For the DataFormatString to be applied in a BoundColumn of a GridView, the HtmlEncode property must be set to False.

I don’t think I understand WHY this is the case, but it’s comforting to know that it’s a definite solution to the problem.