VB.NET : Get MAC address

Imports System.Net.NetworkInformation


Dim macs() As NetworkInterface = NetworkInterface.GetAllNetworkInterfaces()
MsgBox(mac(1).GetPhysicalAddress.ToString)

VB.NET : Create folder if does not exist

'at top import below namespace

Imports System.IO

If Not Directory.Exists("D:\db") Then
        Directory.CreateDirectory("D:\db")
End If

VB.NET : How to add column in existing table or DataTable

'Create Column
Dim dtColumnCurrDate As New DataColumn("date")
Dim dtColumnPatientName As New DataColumn("patient_name")
Dim dtColumnDignosis As New DataColumn("mlc")
Dim dtColumnDate As New DataColumn("total")

'Create DataTable
Dim dtTable As New DataTable

'Add Column to DataTable
dtTable.Columns.Add(dtColumnCurrDate)
dtTable.Columns.Add(dtColumnPatientName)
dtTable.Columns.Add(dtColumnDignosis)
dtTable.Columns.Add(dtColumnDate)

'Create DataRow Object
Dim rowItem As DataRow

'Create row for DataTable
rowItem = dtTable.NewRow()

'Assign value to each column of raw
rowItem(0) = Format(dtpCertiDate.Value, "dd/MM/yyyy")
rowItem(1) = Trim(txtName.Text)
rowItem(2) = Trim(txtDignosis.Text)
rowItem(3) = Format(dtpOnDate.Value, "dd/MM/yyyy")

'Add Row to dataTable
dtTable.Rows.Add(rowItem)