Trying To Populate Dropdown List From SQL Data Source

I am trying to populate a dropdownlist from a sql data source in my codebehind using c#.  I thought I had the code correct but I keep getting the following error and I am stuck:  "Only assignment, call, increment, decrement,  and new object expressions can be used as a statement"

 Here is the code:protected void populateOppNameList(){

SqlConnection conn = new SqlConnection(ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString);SqlCommand cmd = new SqlCommand("SELECT empname FROM opportunity WHERE (username = " + userName + ")", conn);

SqlDataAdapter adapter = new SqlDataAdapter(cmd);

try

{

conn.Open();DataSet ds = new DataSet();DropDownList ddl_OppNames = (DropDownList)FormView1.FindControl("dropdownlist1");

ddl_OppNames.DataSource = ds;

ddl_OppNames.DataBind;}catch (Exception e)

{

}

finally

{if (conn != null) { conn.Close(); }

}

 

}