HOW TO CREATE COMMON ID NUMBER IN VB.NET

FUNCTION FOR CREATE COMMON ID NUMBER
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Public Sub idno() '
Dim dt As New DataTable
Dim cal As String = "select staff_id_no from tb_staff order by staff_id desc"
dt = obj.call1(cal)
If dt.Rows.Count > 0 Then
Dim idno As String = dt.Rows(0)("staff_id_no").ToString
Dim length As Integer = idno.LastIndexOf("/")
Dim length1 As Integer = length + 1
Dim totlength As Integer = idno.Length
Dim totlength1 As Integer = totlength - length1
idno = idno.Substring(length1, totlength1)
Dim idno1 As Decimal = Convert.ToDecimal(idno)
Dim idno2 As Decimal = idno1 + 1
Lblidno.Text = "ANU/09/" + idno2.ToString
Else
Lblidno.Text = "ANU/09/1001"
End If
End Sub
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