Hi I am starting to learn VB.NET and I am little bit confused right now.
I want to create a connection string dynamically at run time.

I made a module for it and I want to call it everytime I need it.

Code:
Imports System.Data.SqlClient
Module Module1
    Public connection As SqlConnection
    Public cmd As SqlCommand
    Public rd As SqlDataReader
    Sub con()
        connection = New SqlConnection
        cmd = New SqlCommand
        connection.ConnectionString = "Server='" & My.Settings.SName & "';user='" & My.Settings.UName & "';password='" & My.Settings.Pword & "';database='" & My.Settings.DBName & "'"

        'Dim connection As New SqlConnection("Server='" & My.Settings.SName & "';user='" & My.Settings.UName & "';password='" & My.Settings.Pword & "';database='" & My.Settings.DBName & "'")

    End Sub
End Module
And now I'm on my login page but I don't know how to call my module or it's not possible.
Here's my login code:
Code:
Imports System.Data.SqlClient
Public Class LoginForm1
    Private Sub OK_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles OK.Click
        con()
        connection.Open()
        cmd.Connection = connection
        cmd.CommandText = "SELECT * from tbl_login where username='" & txtusername.Text & " and password='" & txtpassword.Text & "'"

        If rd.HasRows Then
            Mainform.Show()
        Else
            MsgBox("Invalid Login credentials", MsgBoxStyle.Exclamation, "Failed!")
        End If
    End Sub
By the way I'm using sql server 2008.
Thank you so much