how to fix reference not set to an instance of an object

[Mostafa Zaki]

How do I fix the "reference not set to an instance of an object" error?

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Data.SqlClient;
using System.Configuration;
using System.Data;
using System.Collections;
 
/// <summary>
/// Summary description for DbWork
/// </summary>
public class DbWork
{
    DataTable Tbl;
    SqlConnection con;
    SqlCommand cmd;
    // dbcall means storedproceudre or sql statement
    // method to initialize con to db
    private void Initialize(CommandType CT, string DbCall)
    {
        con = new SqlConnection();
        con.ConnectionString = ConfigurationManager.ConnectionStrings[1].ToString();
        cmd = new SqlCommand();
        cmd.Connection = con;
        cmd.CommandType = CT;
        cmd.CommandText = DbCall;
        con.Open();
    }
    public int RunProcedure(string SpName, SortedList ParaValu)
    {
 
        Initialize(CommandType.StoredProcedure, SpName);
        for (int x = 0; x < ParaValu.Count; x++)
        {
 
            cmd.Parameters.AddWithValue(ParaValu.GetKey(x).ToString(), ParaValu.GetByIndex(x).ToString());
 
        }
        return RunUpdate();
    }
    private int RunUpdate(string UPDEIn) 
    {
        Initialize(CommandType.Text, UPDEIn);  
        return RunUpdate();
    }
 
    private DataTable RunQuery(string Select) 
    {
 
        Initialize(CommandType.Text, Select);
        Tbl = new DataTable();
        Tbl.Load(cmd.ExecuteReader());
        con.Close();
        return Tbl;
 
    }
 
    private int RunUpdate()
    {
 
        try
        {
            int x = cmd.ExecuteNonQuery();
            con.Close();
            return x;
        }
        catch (SqlException ex)
        { 
            con.Close();
            return ex.Number;
 
        }
 
    }
}

[Frinavale]

It would really help if you mentioned what line of code you are getting the Null Reference exception from.

But my guess is that you are getting it on line 23 of the above posted code..

Double check that your web.config contains a Connection String at position 1 (likely you want position 0)

-Frinny