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Stuck with Idatareader object in N-Tier Architecture

Familiar Sight
  
Join Date: Jul 2007
Location: France
Posts: 149
#1: Jul 10 '07
Hi,

I am new to ASP.NET and I am trying to build a CMS application using theBeerHouse SK.

I am adapting the Datareader to collect information from an SQL database and send it to an HtmlHeader. Using N-Tier architecture I keep recieving an object reference required error.

Here's my code:

Home.aspx.cs

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  1. namespace TMG.DAL
  2. {
  3.     public partial class Home : System.Web.UI.Page
  4.     {
  5.         public HeaderDetails findInfo(string pageId)
  6.         {
  7.             HeaderDetails headers = null;
  8.             headers = GetHeader.GetHeaderById(pageId);
  9.             return headers;
  10.         }
  11.         protected void Page_Load(object sender, EventArgs e)
  12.         {
  13.             String pageId = Page.GetType().Name;
  14.             pageId = pageId.Replace("_aspx", "");
  15.             Master.Page.Header.Title = "TMG - Advertisers site - " + pageId;
  16.             //Get the htmlHead your aspx page is using (from the Master page)
  17.             //Master page must include the runat server attribute in the head tag: <head runat="server">
  18.             HtmlHead head = (System.Web.UI.HtmlControls.HtmlHead)Header;
  19.  
  20.             //Create a htmlMeta object
  21.  
  22.             HtmlMeta meta = new HtmlMeta();
  23.             HtmlMeta meta2 = new HtmlMeta();
  24.             HtmlMeta meta3 = new HtmlMeta();
  25.  
  26.             //Specify meta attributes
  27.             meta.Attributes.Add("name", "keywords");
  28.             meta.Attributes.Add("content", "blah");
  29.             meta2.Attributes.Add("name", "description");
  30.             meta2.Attributes.Add("content", "blah");
  31.             meta3.Attributes.Add("name", "abstract");
  32.             meta3.Attributes.Add("content", "blah");
  33.             // Add the meta object to the htmlhead's control collection
  34.             head.Controls.Add(meta);
  35.             head.Controls.Add(meta2);
  36.             head.Controls.Add(meta3);
  37.         }
  38.     }
  39. }
  40.  
  41. HeaderProvider.cs
  42.  
  43. namespace TMG.DAL
  44. {
  45.     public abstract class HeaderProvider : DataAccess
  46.     {
  47.         //public abstract HeaderDetails GetHeaderByID(string pageId);
  48.  
  49.         protected virtual HeaderDetails GetHeaderFromReader(IDataReader reader)
  50.         {
  51.             return GetHeaderFromReader(reader, true);
  52.         }
  53.         protected virtual HeaderDetails GetHeaderFromReader(IDataReader reader, bool readBody)
  54.         {
  55.             HeaderDetails headers = new HeaderDetails(
  56.                 (int)reader["id"],
  57.                null,
  58.                null,
  59.                null,
  60.                reader["javascript"].ToString(),
  61.                reader["title"].ToString(),
  62.                reader["css"].ToString(),
  63.                reader["page_id"].ToString());
  64.  
  65.             if (readBody)
  66.                 headers.AbstractText = reader["abstractText"].ToString();
  67.                 headers.Description = reader["description"].ToString();
  68.                 headers.Keywords = reader["keywords"].ToString();
  69.  
  70.             return headers;
  71.         }
  72.     }
  73. }
  74.  
  75. HeaderDetails.cs
  76.  
  77. namespace TMG.DAL
  78. {
  79.     public class HeaderDetails
  80.     {
  81.         public HeaderDetails(int id, string abstractText, string description, string keywords, string javascript, string title, string css, string page_id)
  82.         {
  83.             this.ID = id;
  84.             this.AbstractText = abstractText;
  85.             this.Description = description;
  86.             this.Keywords = keywords;
  87.             this.Javascript = javascript;
  88.             this.Title = title;
  89.             this.Css = css;
  90.             this.PageId = page_id;
  91.  
  92.  
  93.         }
  94.         private int _id = 0;
  95.         public int ID
  96.         {
  97.             get { return _id; }
  98.             set { _id = value; }
  99.         }
  100.         private string _abstractText = "";
  101.         public string AbstractText
  102.         {
  103.             get { return _abstractText; }
  104.             set { _abstractText = value; }
  105.         }
  106.         private string _description = "";
  107.         public string Description
  108.         {
  109.             get { return _description; }
  110.             set { _description = value; }
  111.         }
  112.         private string _keywords = "";
  113.         public string Keywords
  114.         {
  115.             get { return _keywords; }
  116.             set { _keywords = value; }
  117.         }
  118.         private string _javascript = "";
  119.         public string Javascript
  120.         {
  121.             get { return _javascript; }
  122.             set { _javascript = value; }
  123.         }
  124.         private string _title = "";
  125.         public string Title
  126.         {
  127.             get { return _title; }
  128.             set { _title = value; }
  129.         }
  130.         private string _css = "";
  131.         public string Css
  132.         {
  133.             get { return _css; }
  134.             set { _css = value; }
  135.         }
  136.         private string _pageId = "";
  137.         public string PageId
  138.         {
  139.             get { return _pageId; }
  140.             set { _pageId = value; }
  141.         }
  142.     }
  143. }
  144.  
  145. GetHeader.cs
  146. namespace TMG.DAL
  147. {
  148.     public class GetHeader : HeaderProvider
  149.     {
  150.         private int _id = 0;
  151.         public int ID
  152.         {
  153.             get { return _id; }
  154.             set { _id = value; }
  155.         }
  156.         private string _abstractText = "";
  157.         public string AbstractText
  158.         {
  159.             get { return _abstractText; }
  160.             set { _abstractText = value; }
  161.         }
  162.         private string _description = "";
  163.         public string Description
  164.         {
  165.             get { return _description; }
  166.             set { _description = value; }
  167.         }
  168.         private string _keywords = "";
  169.         public string Keywords
  170.         {
  171.             get { return _keywords; }
  172.             set { _keywords = value; }
  173.         }
  174.         private string _javascript = "";
  175.         public string Javascript
  176.         {
  177.             get { return _javascript; }
  178.             set { _javascript = value; }
  179.         }
  180.         private string _title = "";
  181.         public string Title
  182.         {
  183.             get { return _title; }
  184.             set { _title = value; }
  185.         }
  186.         private string _css = "";
  187.         public string Css
  188.         {
  189.             get { return _css; }
  190.             set { _css = value; }
  191.         }
  192.         private string _pageId = "";
  193.         public string PageId
  194.         {
  195.             get { return _pageId; }
  196.             set { _pageId = value; }
  197.         }
  198.         public GetHeader(int id, string abstractText, string description, string keywords, string javascript, string title, string css, string page_id)
  199.         {
  200.             this.ID = id;
  201.             this.AbstractText = abstractText;
  202.             this.Description = description;
  203.             this.Keywords = keywords;
  204.             this.Javascript = javascript;
  205.             this.Title = title;
  206.             this.Css = css;
  207.             this.PageId = page_id;
  208.  
  209.  
  210.         }
  211.  
  212.         public virtual HeaderDetails GetHeaderById(string pageId)
  213.         {
  214.            SqlConnection cn = GetConnection();
  215.            SqlCommand oCommand = new SqlCommand("page_header",cn);
  216.            oCommand.CommandType=CommandType.StoredProcedure; // Parametrs
  217.            oCommand.Parameters.Add("@pageId", SqlDbType.VarChar).Value = pageId;
  218.            cn.Open();
  219.            IDataReader reader = ExecuteReader(oCommand, CommandBehavior.SingleRow);
  220.            if (reader.Read())
  221.                return GetHeaderFromReader(reader, true);
  222.            else
  223.                return null;
  224.         }
  225.     }
  226. }
  227.  
  228. DataAccess.cs
  229. namespace TMG.DAL
  230. {
  231.     public abstract class DataAccess
  232.     {
  233.         protected static string strConnect;
  234.         public DataAccess()
  235.         {
  236.         } 
  237.  
  238.         static DataAccess()
  239.         {
  240.             strConnect = ConfigurationManager.AppSettings["connstr"];
  241.         } 
  242.  
  243.         protected SqlConnection GetConnection()
  244.         {   
  245.             SqlConnection oConnection = new SqlConnection(strConnect);
  246.             return oConnection;
  247.         }
  248.         protected IDataReader ExecuteReader(DbCommand cmd)
  249.         {
  250.             return ExecuteReader(cmd, CommandBehavior.Default);
  251.         }
  252.  
  253.         protected IDataReader ExecuteReader(DbCommand cmd, CommandBehavior behavior)
  254.         {
  255.             return cmd.ExecuteReader(behavior);
  256.         }
  257.         protected object ExecuteScalar(DbCommand cmd)
  258.         {
  259.             return cmd.ExecuteScalar();
  260.         }
  261.     }
  262. }
Sorry for all the code.
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