I have a gridview in asp.net 2.0 which is late bound to a datasource
depending upon user selections on the form.  The data shows up in the
grid, but clicking on the column headers does not sort the data and
causes it to disappear.

How can I handle the sort so that it works?

Here is the code:
  Dim mywhere As String
             Dim repview, selectstring As String
             Dim myarg As New System.Web.UI.DataSourceSelectArguments()

'select clause that detects which report to load
             Select Case Me.ddReptype.SelectedValue
                ....

                 Case 3 'Quality
                     repview = "QualityRepView"

             End Select
             selectstring = "select * from " & repview


             'gets where clause from various dropdownlists
                 mywhere = getWhereClause()

                 selectstring += " Where " & mywhere

                  Me.GridView1.AllowSorting = True

                 Me.SDSReports.SelectCommand = selectstring
                 Me.SDSReports.Select(myarg)
                 Me.GridView1.DataSourceID = "SDSReports"
                 'Me.GridView1.DataSource = Me.SqlDataSource1


                 Me.GridView1.DataBind()