Input_Volt.Focus()

Public Class tyfoo
    ' [TYFOO]:.
 
    Dim LED_mA_r As String
    Dim LED_Ampere_r As String
    Dim LED_Watt_r As String
    Dim LED_Spannung_r As String
    Dim Widerstand_Volt_r As String
    Dim Widerstand_Ohm_r As String
    Dim Widerstand_Watt_r As String
    Dim Input_Volt_r As String
 
    Private Sub tyfoo_FormClosing(ByVal sender As System.Object, ByVal e As _
      System.Windows.Forms.FormClosingEventArgs) Handles MyBase.FormClosing
        If MessageBox.Show("Beenden?", _
  "[TYFOO]:.", MessageBoxButtons.YesNo, MessageBoxIcon.Information, _
  MessageBoxDefaultButton.Button2) = Windows.Forms.DialogResult.No Then
            e.Cancel = True
        End If
    End Sub
 
    Private Sub Input_Volt_KeyPress(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.KeyPressEventArgs) Handles Input_Volt.KeyPress
        Select Case AscW(e.KeyChar)
            Case 44, 46, 48 To 57, 8
            Case Else
                e.Handled = True
 
        End Select
    End Sub
 
    Private Sub LED_mA_KeyPress(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.KeyPressEventArgs) Handles LED_mA.KeyPress
        Select Case AscW(e.KeyChar)
            Case 44, 46, 48 To 57, 8
            Case Else
                e.Handled = True
        End Select
    End Sub
 
    Private Sub LED_Spannung_KeyPress(ByVal sender As Object, ByVal e As _
      System.Windows.Forms.KeyPressEventArgs) Handles LED_Spannung.KeyPress
        Select Case AscW(e.KeyChar)
            Case 44, 46, 48 To 57, 8
            Case Else
                e.Handled = True
        End Select
    End Sub
 
    Private Sub calc_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles calc.Click
        If Input_Volt.Text = "" Or Input_Volt.Text = "," Then
            MsgBox("Eingabe inkorrekt!", MessageBoxButtons.OK, "Fehler")
            Input_Volt.Focus()
            Exit Sub
        End If
        If LED_Spannung.Text = "" Or Input_Volt.Text = "," Then
            MsgBox("Eingabe inkorrekt!", MessageBoxButtons.OK, "Fehler")
            LED_Spannung.Focus()
            Exit Sub
        End If
        If LED_mA.Text = "" Or Input_Volt.Text = "," Then
            MsgBox("Eingabe inkorrekt!", MessageBoxButtons.OK, "Fehler")
            LED_mA.Focus()
            Exit Sub
        End If
 
        Input_Volt_r = Input_Volt.Text
        LED_mA_r = LED_mA.Text
        LED_Spannung_r = LED_Spannung.Text
 
        LED_Ampere_r = LED_mA_r / 1000
        LED_Watt_r = LED_Spannung_r * LED_Ampere_r
        Widerstand_Volt_r = Input_Volt_r - LED_Spannung_r
        Widerstand_Ohm_r = Widerstand_Volt_r / LED_Ampere_r
        Widerstand_Watt_r = Widerstand_Volt_r * LED_Ampere_r
 
        ergebnis1.Text = LED_Watt_r
        ergebnis2.Text = Widerstand_Ohm_r
        ergebnis3.Text = Widerstand_Watt_r
    End Sub
End Class

[TYFOO]:.