public declaration of connetion open and close to the database vb.net

Public con As String = "Provider=SQLOLEDB;Data Source=315mis\wdc1;Initial Catalog=sample;User Id=sa;Password=P@ssw0rd;"
    Public cnSQL As New OleDbConnection
    Public cmSQL As New OleDbCommand
    Public strSQL As String
    Public objRead As OleDbDataReader
    Public currenttab As Integer
    Public ds As New DataSet
    Public lv As ListViewItem

   
    Public Sub connection_open()
        cnSQL = New OleDbConnection(con)
        cnSQL.Open()
    End Sub

    Public Sub connection_close()
        cnSQL.Close()
        cnSQL.Dispose()
    End Sub