Hi,
I'm a student who's working on a school project about ASP.NET / C#.
I'm having some problems with my class. I want to create an ArrayList
filled with results from a DataReader. It gives me the following
error:
Exception Details: System.NullReferenceException: Object reference not
set to an instance of an object.
Line 29: MyDataObject.CreateArray();
When I remove this sentence everything works fine. I'm a newbie to
ASP.NET / C# so I hope someone can help me.
Thanks in advance,
Gorden Blom (ti-mon3aan)
Here's the code..
codebehind:
using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Text;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
//custom classes
using Gorden.CustomClass;
namespace Test {
public class MyCodeBehind : Page {
protected System.Web.UI.WebControls.Repeater rptMenu;
public void Page_Load(object sender, System.EventArgs e) {
DataObject MyDataObject = new DataObject();
MyDataObject.Open();
SqlDataReader MyReader = MyDataObject.sqlReader("SELECT *
FROM [Categorie]", rptMenu);
MyDataObject.CreateArray();
MyDataObject.CloseReader();
MyDataObject.Close();
}
#region Web Form Designer generated code
override protected void OnInit(EventArgs e) {
InitializeComponent();
base.OnInit(e);
}
private void InitializeComponent() {
this.Load += new System.EventHandler(this.Page_Load);
}
#endregion
}
}
class:
using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Data.SqlClient;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
namespace Gorden.CustomClass {
public class DataObject {
private SqlConnection sqlCon;
private SqlDataReader returnReader;
public ArrayList MyArrayList;
public DataTable schemaTable;
public DataObject() {
sqlCon = new
SqlConnection(ConfigurationSettings.AppSettings.Ge t("connectionstring"));
}
public void Open() {
this.sqlCon.Open();
}
public void Close() {
this.sqlCon.Close();
}
public SqlDataReader sqlReader(string strSql, Repeater rptRep)
{
SqlCommand command = new SqlCommand(strSql, this.sqlCon);
returnReader = command.ExecuteReader();
this.dataBind(rptRep);
return returnReader;
}
public void dataBind(Repeater RptRep) {
RptRep.DataSource = returnReader;
RptRep.DataBind();
}
public void CreateArray() {
schemaTable = returnReader.GetSchemaTable();
string strData;
strData = null;
foreach (DataRow myRow in schemaTable.Rows) {
strData = myRow[0].ToString();
MyArrayList.Add(strData);
}
}
public void CloseReader() {
returnReader.Close();
}
}
}
