Please Solve this Erro

MenuItem menu = new MenuItem();
            if (con.State == ConnectionState.Closed)
            {
                con.Open();
            }
            SqlCommand cmd = new SqlCommand("SP_DemoMenu", con);
            cmd.CommandType = CommandType.StoredProcedure;
            DataSet ds = new DataSet();

            SqlDataAdapter adpt = new SqlDataAdapter(cmd);
            adpt.Fill(ds);
            con.Close();
          
           foreach (DataRowView item in mainMen)
            {
                MenuItem Mmnu = new MenuItem(item["MenuName"].ToString(),
                item["MenuId"].ToString(), "", item["Url"].ToString());
                mainMenu.Items.Add(Mmnu);
                subMenu.RowFilter = "MenuId = " + Mmnu.Value;
                foreach (DataRowView subItem in subMenu)
                {
                MenuItem sMnu = new MenuItem(subItem["SubMenuName"].ToString(), 
                subItem["SubMenuId"].ToString(), "", subItem["MenuUrl"].ToString());
                mainMenu.Items[Convert.ToInt32(Mmnu.Value)-1].ChildItems.Add(sMnu);
                subChildMenu.RowFilter = "MenuId = " + Mmnu.Value + " And SubMenuID = " + sMnu.Value;
                foreach (DataRowView childItem in subChildMenu)
                {
                MenuItem chldMnu = new MenuItem(childItem["ChildMenuName"].ToString(),"","", childItem["MenuUrl"].ToString());
            mainMenu.Items[Convert.ToInt32(Mmnu.Value) - 1].ChildItems[Convert.ToInt32(sMnu.Value) - 1].ChildItems.Add(chldMnu);
        }
    }    
}

Server Error in '/' Application.
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: CS0103: The name 'mainMen' does not exist in the current context

Source Error:


Line 30:             con.Close();
Line 31:           
Line 32:            foreach (DataRowView item in mainMen)
Line 33:             {
Line 34:                 MenuItem Mmnu = new MenuItem(item["MenuName"].ToString(),