Private Sub Button10_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button10.Click
        Dim instance As DateTime = Now()
        Dim value As Double
        Dim returnValue As DateTime
        Dim datNewDate As DateTime = AddWorkingDays(Today, +20)
        'MessageBox.Show("The last working day was " & datNewDate)
        TextBox1.Text = Today
        If TextBox1.Text = New Date Then
            dateindev.Text = TextBox1.Text + instance.AddDays(20)
        End If
        returnValue = instance.AddDays(20)
        dateindev.Text = returnValue
        Me.dateindev.Text = returnValue.ToLongDateString
    End Sub



    Public Function AddWorkingDays(ByVal DateIn As DateTime, _
           ByVal ShiftDate As Integer) As DateTime
        ' Adds the [ShiftDate] number of working days to DateIn
        Dim datDate As DateTime = DateIn.AddDays(ShiftDate)
        ' Loop around until we get the need non-weekend day
        While Weekday(datDate) = 1 Or Weekday(datDate) = 7    
             datDate = datDate.AddDays(IIf(ShiftDate < 0, -1, 1))
        End While
        Return datDate
    End Function