How to display database connection status in VB 2010 - database

Question

I'm developing Point of sales system. and i want to display database connection status for the users. Im using MS Access 2013 database and Visual Studio 2010 (VB). I created module for this project as follows,
Imports System.Data.OleDb
Module ModConVar
Public sql As String
Public cmd As OleDbCommand
Public dr As OleDbDataReader
Public conn As OleDbConnection
Public connStr As String = System.Environment.CurrentDirectory.ToString & "\NCS_POS_DB.accdb"
Public Sub ConnDB()
Try
conn = New OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" & connStr & "")
conn.Open()
Catch ex As Exception
MsgBox(ex.Message)
End Try
End Sub
End Module
And I have a label named lblDBStatus in main MDI form, I tried with followin code, but it dosent work.
If conn.State = ConnectionState.Open Then
lblDBStatus.Text = "CONECTED"
End If
any suggestions please ??

Answer 1

You're displaying "CONNECTED" only when the connection state is open. Otherwise your label will not show anything
Try this and make sure that the connection is open:
If conn.State = ConnectionState.Open Then
lblDBStatus.Text = "CONNECTED"
Else
lblDBStatus.Text = "DISCONNECTED"
End If

Answer 2

The OleDbConnection exposes a StateChanged event.
So you can track the state like this:
Public Sub ConnDB()
Using connection As New OleDbConnection("...")
AddHandler connection.StateChange, AddressOf Me.OnConnectionStateChange
Try
connection.Open()
'Do stuff..
Catch ex As Exception
Throw ex
Finally
RemoveHandler connection.StateChange, AddressOf Me.OnConnectionStateChange
End Try
End Using
End Sub
Private Sub OnConnectionStateChange(sender As Object, e As StateChangeEventArgs)
MessageBox.Show(e.CurrentState.ToString())
End Sub