Bind DropDown List

public void bindDropDownsss()
    {

        SqlConnection con = new SqlConnection(ConfigurationManager.ConnectionStrings["db2ConnectionString1"].ConnectionString);
        string query = "select * from Employee_Details ";
        SqlDataAdapter sda = new SqlDataAdapter(query, con);
        DataTable dt = new DataTable();
        sda.Fill(dt);
        ddl.DataSource = dt;
        ddl.DataBind();
        ddl.DataTextField="UserName";
        ddl.DataValueField = "UserId";
        ddl.DataBind();
         
     
    }