[02/03]

Hi all,

I am new to the VB.net. I am trying to connect db with very simple code but giving following error:

An unhandled exception of type 'System.NullReferenceException' occurred in TestConn.exe

Additional information: Object reference not set to an instance of an object.

See the CODE below:

Imports System.Data
Imports System.Data.OleDb
Imports System.Data.SqlClient

Public Class Form1
Inherits System.Windows.Forms.Form
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim con As OleDb.OleDbConnection
con.ConnectionString = "PROVIDER=Microsoft.Jet.OLEDB.4.0;Data Source = C:\Documents and Settings\img\My Documents\Visual Studio Projects\TestConn\AddressBook.mdb"
con.Open()
MsgBox("A Connection to the Database is now open")
con.Close()
MsgBox("The Connection to the Database is now Closed")
End Sub
End Class

Pls help me to solve the prob.

Thanks,
Gitesh

Before you can use the 'con' variable, you must use the 'New' instruction for the compiler to allocate a valid reference to your variable.

your code should be like this

vb Code:

Imports System.Data
Imports System.Data.OleDb
Imports System.Data.SqlClient
 
Public Class Form1 
         Inherits System.Windows.Forms.Form
    
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
       Dim con As New OleDb.OleDbConnection
       con.ConnectionString = "PROVIDER=Microsoft.Jet.OLEDB.4.0;Data Source = C:\Documents and Settings\img\My Documents\Visual Studio Projects\TestConn\AddressBook.mdb"
       con.Open()
       MsgBox("A Connection to the Database is now open")
       con.Close()
       MsgBox("The Connection to the Database is now Closed")
    End Sub
End Class

Yes, to brief you need to change just one line of your code.

vb Code:

Dim con As New OleDb.OleDbConnection 'New keyword added

Thanks talkro...Problem Solved.