.net: how to evaluate this error - vb.net

Question

I am new to vb.net and I am trying to create a login form but on running this code i get error msg("ExecuteReader: Connection property has not been initialized.")
Imports System
Imports System.Data
Imports System.Data.OleDb
Public Class Form1
Dim con As New System.Data.OleDb.OleDbConnection
Dim cmd As System.Data.OleDb.OleDbCommand
Dim da As System.Data.OleDb.OleDbDataAdapter
Dim sdr As System.Data.OleDb.OleDbDataReader
Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
Dim dbprovider As String = "Provider=Microsoft.jet.OleDb.4.0;"
Dim dbsource As String = "Data Source=C:\Users\RAJKRI\Documents\Visual Studio 2008\Projects\Banking System.mdb"
con.ConnectionString = dbprovider & dbsource
con.Open()
cmd.Connection = con
End Sub
Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
'Dim con As New OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=C:\Users\RAJKRI\Documents\Visual Studio 2008\Projects\Banking System.accdb")
cmd = New OleDb.OleDbCommand("SELECT * FROM Login WHERE Empid = '" & TextBox1.Text & "' AND password = '" & TextBox2.Text & "' , con")
sdr = cmd.ExecuteReader()
If (sdr.Read() = True) Then
Form2.Show()
TextBox1.Text = ""
TextBox2.Text = ""
Else
MessageBox.Show("Invalid Employee Id/Password")
End If
End Sub
Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
TextBox1.Text = ""
TextBox2.Text = ""
End Sub
End Class

Answer 1

You are appending your connection object to your query as text. Change
cmd = New OleDb.OleDbCommand("SELECT * FROM Login WHERE Empid = '" & TextBox1.Text & "' AND password = '" & TextBox2.Text & "' , con")
to
cmd = New OleDb.OleDbCommand("SELECT * FROM Login WHERE Empid = '" & TextBox1.Text & "' AND password = '" & TextBox2.Text & "'" , con)
(the difference is at the end)