ASP.NET C# GridView.ShowHeader and other properties

I am using an ASP.NET GridView control, created dynamically with C# on a SharePoint web part. I am having some troubles setting the properties. Specifically, the ShowHeader property seems to be completely ignored, and it is set like so:

gv.ShowHeader = false;

This seems to work fine with the System.Web.UI.WebControls.DataGrid, which I had previously used. I'm also having this issue with many of the other properties, such as BorderColor, BorderWidth, etc. However, CellPadding and CellSpacing work just fine when set similarly:

gv.CellPadding = 2;
gv.CellSpacing = 2;

I don't understand where the problem is. Here is the DataGrid code I had been using, which worked fine:

SqlDataAdapter da = new SqlDataAdapter();
da.SelectCommand = cmd;
DataSet ds = new DataSet();
da.Fill(ds, "Specs");
DataSet flipped_ds = FlipDataSet(ds);
DataView dv = flipped_ds.Tables[0].DefaultView;
DataGrid outputGrid = new DataGrid();
outputGrid.DataSource = dv;
outputGrid.DataBind();
outputGrid.ShowHeader = false;
Controls.Add(outputGrid);

Here is the code that I have replaced this with for my GridView:

SqlDataAdapter da = new SqlDataAdapter();
da.SelectCommand = cmd;
DataSet ds = new DataSet();
da.Fill(ds, "Bobst Specs");
DataSet flipped_ds = FlipDataSet(ds);
DataView dv = flipped_ds.Tables[0].DefaultView;
GridView gv = new GridView();
gv.DataSource = dv;
gv.DataBind();
gv.AutoGenerateColumns = true;
gv.CellPadding = 2;
gv.CellSpacing = 2;
gv.ShowHeader = false;
Controls.Add(gv);

Thanks for any help that I can get!

have you tried setting the gv properties first and then binding?

3 possible solutions --Try disable AutoGeneratedColumns

                gv.AutoGenerateColumns = false; 

--Try add the control to the page first before setting any property

Or --Try a datatable instead and see if it works

                SqlDataAdapter da = new SqlDataAdapter(); 
                da.SelectCommand = cmd; 
                DataTable dt= new DataTable();
                dt.TableName = "Data";
                da.Fill(dt); 
                GridView gv = new GridView(); 
                gv.DataSource = dt; 
                gv.DataBind(); 
                gv.AutoGenerateColumns = true; 
                gv.CellPadding = 2; 
                gv.CellSpacing = 2; 
                gv.ShowHeader = false; 
                Controls.Add(gv);