[RESOLVED] Datetimepicker Calculation

[HOTFIX]

HI...

I've got a form with following controls:
Two Datetimepickers
Two Buttons
One TextBox
One ComboBox



The idea is adding and subtracting dates using Datetimepicker contols...

I found codes for doing Dates Calculation but is'nt quit correct;for example:
if i want to add 21years from today the result will be:
sat 30 Aug 1930



The Adding Codes on comand button:

Private Sub BTNadd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BTNadd.Click
        Dim Date1, NewDate As DateTime
        Date1 = DateTimePicker1.Text
        If ComboBox1.SelectedItem = "DAYS" Then
            NewDate = Date1.AddDays(TextBox1.Text)
            DateTimePicker2.Text = NewDate
        ElseIf ComboBox1.SelectedItem = "WEEKS" Then
            NewDate = Date1.AddDays((TextBox1.Text) * 7)
            DateTimePicker2.Text = NewDate
        ElseIf ComboBox1.SelectedItem = "MONTHS" Then
            NewDate = Date1.AddMonths(TextBox1.Text)
            DateTimePicker2.Text = NewDate
        ElseIf ComboBox1.SelectedItem = "YEARS" Then
            NewDate = Date1.AddYears(TextBox1.Text)
            DateTimePicker2.Text = NewDate
        End If
    End Sub

The Subtracting Codes on comand button:

Private Sub BTNsub_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles BTNsub.Click
        Dim Date1, NewDate As DateTime
        Date1 = DateTimePicker1.Text
        If ComboBox1.SelectedItem = "DAYS" Then
            NewDate = Date1.AddDays(-TextBox1.Text)
            DateTimePicker2.Text = NewDate
        ElseIf ComboBox1.SelectedItem = "WEEKS" Then
            NewDate = Date1.AddDays(-(TextBox1.Text) * 7)
            DateTimePicker2.Text = NewDate
        ElseIf ComboBox1.SelectedItem = "MONTHS" Then
            NewDate = Date1.AddMonths(-TextBox1.Text)
            DateTimePicker2.Text = NewDate
        ElseIf ComboBox1.SelectedItem = "YEARS" Then
            NewDate = Date1.AddYears(-TextBox1.Text)
            DateTimePicker2.Text = NewDate
        End If
    End Sub

Anybody help me to correct the code PLZ ...