How to retrive dynamic dropdownlist data insde the dynamic gridview

hi,

i have added columns to the gridview like this dynamically

BoundField bField = new BoundField();
bField.HeaderText = Label6.Text;
GridView2.Columns.Add(bField);

for to get dropdownlist inside the gridview i have written code like this in GridView2_RowCreated event

TableCell tc = new TableCell();
DropDownList ddlnewList = new DropDownList();
e.Row.Cells.Add(tc);

for to get the selected value from dropdownlist i have written like this in button_Clkick event
if (r.RowType == DataControlRowType.DataRow)
{
foreach (GridViewRow r in GridView2.Rows)
{
DropDownList box1 = (DropDownList)GridView2.Rows[i].Cells[1].FindControl("ddlnewList");
string s= box1.SelectedItem.Text;
}
}


but i am getting null value at box1

Thanks in advance..