I recently had this problem too when I was trying to pass two variables. I figured out a way, but since one of the variables was not dependant on the datagrid, I don't think it'll help you much, but here's the code i used:
Dim col As New HyperLinkColumn()
col.DataNavigateUrlField = _your field_
col.DataNavigateUrlFormatString = Request.FilePath() & "?id={0}&proj=" & TextBox1.Text
Maybe this will give some idea? Notorious SMC
The difference between the almost-right word & the right word is a really large matter - it's the difference between the lightning bug and the Lightning Mark Twain
Get your facts first, and then you can distort them as much as you please Mark Twain