Question

So I’ve been working on learning LINQ, and I think I’m doing this correctly, but when I spit out the value of the DropDownList’s DataValueField property, it comes back as the string “mId” rather than the actual value (the menu_id). Even more strange, the DataTextField is being populated correctly, using the same syntax. Anyone have any ideas?

Here’s my code:

    protected void Page_Load(object sender, EventArgs e)
    {
        List<RobDAL.Menu.menuObj> menuInfo = new List<RobDAL.Menu.menuObj>();
        menuInfo = RobDAL.Menu.GetMenuText();

        menu.DataSource = from myMenu in menuInfo
                          select new { Text = myMenu.menuText,
                                        mId = myMenu.menuId };


        menu.DataValueField = "mId";
        menu.DataTextField = "Text";

        menu.DataBind();

    }

Here’s my Menu class:

public class Menu
{
    public static int GetMainMenuByContentId(int contentid)
    {            
        //SqlConnection connection = new SqlConnection(Configuration.ConnectionInfo);
        Content myContent = new Content();
        int menuid;

        string queryString = "SELECT menu_id FROM menu_to_item_tbl where content_id = " + contentid + ";";
        using (SqlConnection connection = new SqlConnection(Configuration.ConnectionInfo))
        {
            SqlCommand command = new SqlCommand(queryString, connection);
            connection.Open();

            try
            {
                menuid = (int)command.ExecuteScalar();
            }
            finally
            {
                // Always call Close when done reading.
                connection.Close();
            }

            return menuid;
        }
    }

    public static List<menuObj> GetMenuText()
    {
        //SqlConnection connection = new SqlConnection(Configuration.ConnectionInfo);



        List<menuObj> allMenus = new List<menuObj>();

        string queryString = "SELECT DISTINCT menu_id, menu_title FROM menu_to_item_tbl;";
        using (SqlConnection connection = new SqlConnection(Configuration.ConnectionInfo))
        {
            SqlCommand command = new SqlCommand(queryString, connection);
            connection.Open();
            SqlDataReader reader = command.ExecuteReader();
            try
            {
                while (reader.Read())
                {
                    menuObj myMenu = new menuObj();
                    myMenu.menuId = Convert.ToInt16(reader[0]);
                    myMenu.menuText = reader[1].ToString();

                    allMenus.Add(myMenu);
                }

            }
            finally
            {
                reader.Close();
            }

            return allMenus;
        }
    }

    public class menuObj
    {
        public string menuText { get; set; }
        public int menuId { get; set; }
    }

}

Thanks!

Answer 1

Change

  menu.DataSource = from myMenu in menuInfo
                          select new { Text = myMenu.menuText,
                                        mId = myMenu.menuId };

to

  menu.DataSource = (from myMenu in menuInfo
                          select new { Text = myMenu.menuText,
                                        mId = myMenu.menuId }).ToList();;