Click here to Skip to main content
11,480,031 members (66,012 online)
Rate this: bad
good
Please Sign up or sign in to vote.
See more: C#2.0 C#3.0 C# SQL C#4.0
OleDbConnection cn;
public ExpireProduct()
{
    InitializeComponent();       
    cn = new OleDbConnection(@"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=D:\MIS SYSTEM\AniPharmic\AniPharmic\MedicalDb.accdb;Jet OLEDB:Database Password=****");          
}
try
{
    con.Open();
    str = "select *from DatabaseLogin where user_id='" + textBox2.Text + "'";
    com = new OleDbCommand(str, con);
    OleDbDataReader reader = com.ExecuteReader();
    while (reader.Read())
    {
       checkedListBox1.Items.Add(reader["stckdemge"]);
    }
}
catch (Exception ex)
{
    MessageBox.Show(" " + ex);
}


Error is In this Line 4 -
con.Open();

Error is :- Cannot open Connection:System.NullReferenceException:Object Reference Not
set to an instance of an object.
Posted 28-Feb-13 16:43pm
Edited 28-Feb-13 20:21pm
v2
Comments
ZaneArellano at 1-Mar-13 1:23am
   
where did that con came from? your connection is named cn
Rate this: bad
good
Please Sign up or sign in to vote.

Solution 1

You have declared cn while declaring the connection object.
While using it, you have written con. Change it to cn and see if the error is still there.
  Permalink  
Rate this: bad
good
Please Sign up or sign in to vote.

Solution 2

because declared cn so you should write cn.open()
write this...
try
           {
              cn.Open();
               str = "select *from DatabaseLogin where user_id='" + textBox2.Text + "'";
               com = new OleDbCommand(str, cn);
               OleDbDataReader reader = com.ExecuteReader();
               while (reader.Read())
               {
                   checkedListBox1.Items.Add(reader["stckdemge"]);
               }
 

 
           }
           catch (Exception ex)
           {
               MessageBox.Show(" " + ex);
           }
Happy Coding!
Smile | :)
  Permalink  

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

  Print Answers RSS
0 OriginalGriff 235
1 Sergey Alexandrovich Kryukov 215
2 Richard MacCutchan 100
3 F-ES Sitecore 75
4 DamithSL 65
0 Sergey Alexandrovich Kryukov 7,890
1 OriginalGriff 7,556
2 Sascha Lefèvre 3,064
3 Maciej Los 2,491
4 Richard Deeming 2,335


Advertise | Privacy | Mobile
Web04 | 2.8.150520.1 | Last Updated 1 Mar 2013
Copyright © CodeProject, 1999-2015
All Rights Reserved. Terms of Service
Layout: fixed | fluid

CodeProject, 503-250 Ferrand Drive Toronto Ontario, M3C 3G8 Canada +1 416-849-8900 x 100