Populate 2 Level (Multi Level) HTML Menu from SQL Server database in ASP.Net

hi

refer below link

http://www.aspforums.net/Threads/999041/bind-2-level-menu-from-database/?s=2#Replies

I use code for 2levelmenu now I want bind it from database so I change code like below

    private DataTable GetMenu()
    {
        using (SqlConnection conn = General.GetConnection())
        {
            using (SqlCommand _cmd = General.GetCommand("BindMenu", conn))
            {
                DataTable dt = new DataTable();
                SqlDataAdapter sda = new SqlDataAdapter();
                conn.Open();
                sda.SelectCommand = _cmd;
                sda.Fill(dt);
                return dt;
            }
        }
 protected DataTable GetSubMenu(string manuId)
    {
         using (SqlConnection conn = General.GetConnection())
        {
            using (SqlCommand _cmd = General.GetCommand("Bind2levelMenu", conn))
            {
                _cmd.Parameters.Add("@MenuId", string.Format("menuId = {0}", manuId));
                DataTable dt = new DataTable();
                try
                {
                        conn.Open();
                        SqlDataReader reader = _cmd.ExecuteReader();
                        if (reader.HasRows)
                        {
                            dt.Load(reader);
                        }
                        reader.Close();      
                }
                 catch (Exception)
                {
                    return new DataTable();
                }
            }
         }

  protected void rptMenu_ItemDataBound(object sender, RepeaterItemEventArgs e)
    {
        Repeater rptSubMenu = e.Item.FindControl("rptSubMenu") as Repeater;
        string manuId = (e.Item.DataItem as DataRowView)["Id"].ToString();
        rptSubMenu.DataSource = this.GetSubMenu(manuId);
        rptSubMenu.DataBind();
    }

and SP

create procedure [dbo].[Bind2levelMenu]
@MenuId int
as
begin
select *
from Menu
where Id=@MenuId
end

but this error happen:

Compilation Error

Description: An error occurred during the compilation of a resource required to service this request. Please review the following specific error details and modify your source code appropriately.  Compiler Error Message: CS0161: 'menu.GetSubMenu(string)': not all code paths return a value Source Error:

Line 115:
Line 116:
Line 117:    protected DataTable GetSubMenu(string manuId)
Line 118:    {
Line 119:     

I think I worte below metod wrong

 protected DataTable GetSubMenu(string manuId)

can you help me please

Best Regards

Neda