Dynamic Sort Column And Sort Order Not Working

I am trying to set sorting up on a DataGrid in ASP.NET 2.0.  I have it working so that when you click on the column header, it sorts by that column, what I would like to do is set it up so that when you click the column header again it sorts on that field again, but in the opposite direction.
 
I have it working using the following code in the stored procedure:
 
  CASE WHEN @SortColumn = 'Field1' AND @SortOrder = 'DESC' THEN Convert(sql_variant, FileName) end DESC,
case when @SortColumn = 'Field1' AND @SortOrder = 'ASC' then Convert(sql_variant, FileName) end ASC,
case WHEN @SortColumn = 'Field2' and @SortOrder = 'DESC' THEN CONVERT(sql_variant, Convert(varchar(8000), FileDesc)) end DESC,
case when @SortColumn = 'Field2' and @SortOrder = 'ASC' then convert(sql_variant, convert(varchar(8000), FileDesc)) end ASC,
case when @SortColumn = 'VersionNotes' and @SortOrder = 'DESC' then convert(sql_variant, convert(varchar(8000), VersionNotes)) end DESC,
case when @SortColumn = 'VersionNotes' and @SortOrder = 'ASC' then convert(sql_variant, convert(varchar(8000), VersionNotes)) end ASC,
case WHEN @SortColumn = 'FileDataID' and @SortOrder = 'DESC' THEN CONVERT(sql_variant, FileDataID) end DESC,
case WHEN @SortColumn = 'FileDataID' and @SortOrder = 'ASC' THEN CONVERT(sql_variant, FileDataID) end ASC
 
 And I gotta tell you, that is ugly code, in my opinion.  What I am trying to do is something like this:
 
 case when @SortColumn = 'Field1' then FileName end,
case when @SortColumn = 'FileDataID' then FileDataID end,
case when @SortColumn = 'Field2' then FileDesc
when @SortColumn = 'VersionNotes' then VersionNotes
end

case when @SortOrder = 'DESC' then DESC
when @SortOrder = 'ASC' then ASC
end
 
 and it's not working at all, i get an error saying:  Incorrect syntax near the keyword 'case'
 
when i put a comma after the end on line  5 i get: Incorrect syntax near the keyword 'DESC'
 
What am I missing here?
 
Thanks in advance for any help
 
-Madrak