For i As Integer = 0 To 19 ' 20 Durchläufe

   If ... Then Continue For
   If ... Then Exit For

Next i

For i As Single = 0 To 1 Step 0.05
  MsgBox(i.ToString) 'Letzter Index nicht 1 sondern 0,9500002!
Next

Public Class Form1

  Private Sub Form1_Load(ByVal sender As System.Object, ByVal e _
          As System.EventArgs) Handles MyBase.Load
    Dim MyArray() As String = New String() {"Heidelbeeren", _
        "Cherimoya", "Gurken", "Curuba", "Pflaumen", "Durian", _
        "Kirschen", "Datteln", "Himbeere", "Guave", "Birnen", _
        "Mango", "Erdbeeren", "Papaya"}

    For i As Integer = 0 To MyArray.GetUpperBound(0) Step 2
      ListBox1.Items.Add(MyArray(i))
      ListBox2.Items.Add(MyArray(i + 1))
    Next
  End Sub

End Class

For i As Integer = 250 To 155 Step -1
  Button1.BackColor = Color.FromArgb(i, i, i)
  Threading.Thread.Sleep(10)
  Button1.Refresh()
Next

For Each printer As String In _
    Printing.PrinterSettings.InstalledPrinters
  If ... Then Continue For
  If ... Then Exit For
Next

Dim diPfad As New IO.DirectoryInfo("c:\windows")

For Each file As IO.FileInfo In diPfad.GetFiles()
  ListBox1.Items.Add(file.Name.ToString & "  " & _
       file.LastWriteTime.ToShortDateString)
Next

Do
  If ... Then Continue Do
  If ... Then Exit Do
Loop

• Until (Ausführung bis [Anweisung]) oder
• While (Ausführung während [Anweisung])
• kann am Kopf oder Fuß der Schleife stehen
• Schleife ohne Bedingung ist ebenso zulässig

Beispiel 8, Die Do/Loop-Schleifenformen im Überblick:

=== Kopfbedingung Until ===

 ' Ende wenn Until-Bedingung den Schleifenkopf erreicht
Do Until ComboBox1.Items.Count > 90

=== Fußbedingung Until ===

 ' Ende wenn Until-Bedingung das Schleifenende erreicht
Loop Until ComboBox1.Items.Count > 90

=== Kopfbedingung While ===

 ' Läuft solange While-Bedingung am Schleifenkopf vorliegt
Do While ComboBox1.Items.Count > 90

=== Fußbedingung While ===

 ' Läuft solange While-Bedingung am Schleifenende vorliegt
Loop While ComboBox1.Items.Count > 90

While ComboBox1.Items.Count < 90
  If ... Then Continue While
  If ... Then Exit While
End While

Dim i As Integer, k As Integer

 'äußere Schleife
For k = 1 To 5
   'erste innere Schleife
  For i = 1 To 20

  Next i

   'zweite innere Schleife
  For i = 1 To 20

  Next i

Next k

 'abschließende separate Schleife
For i = 1 To 20

Next i

Dim rows As Integer = 4
Dim cols As Integer = 4
Dim arr(rows - 1, cols - 1) As Integer
Dim row, col, i As Integer

For row = 0 To rows - 1
  For col = 0 To cols - 1
    arr(row, col) = i
    i += 1
  Next col
Next row

 '2 dim. Array auslesen
For row = 0 To rows - 1
  For col = 0 To cols - 1
    MsgBox(arr(row, col))
  Next col
Next row

Dim i As Integer, j As Integer, Ergebnis As String = ""
Dim Alphabet As String = "ABCDEFGH"

 ' äußere Schleife
For i = 0 To 7
   ' innere Schleife
  For j = 0 To i '<- i ist auch hier im Einsatz!
    Ergebnis += Alphabet.Chars(i)
  Next j
  Ergebnis += vbNewLine
Next i

MessageBox.Show(Ergebnis)

For i As Integer = 1 To 2000
  Label1.Text = i.ToString
  Application.DoEvents() 'ohne DoEvents stockt die Form!
Next

Imports System.Threading

Public Class Form1

Delegate Sub UpdateLabel(ByVal Wert As String)
Dim T As Thread, Counter As Integer

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e _
      As System.EventArgs) Handles MyBase.Load
  Button1.Text = "Starten"
  Button2.Text = "Abbruch"
End Sub

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e _
      As System.EventArgs) Handles Button1.Click
  Counter = 0
  T = New Thread(AddressOf ThreadZiel)
  T.Start()
End Sub

Private Sub Button2_Click(ByVal sender As System.Object, ByVal e _
      As System.EventArgs) Handles Button2.Click
   ' Threadabbruch!
  If T.ThreadState = ThreadState.WaitSleepJoin Or T.ThreadState = _
       ThreadState.Running Then
    T.Abort()
    MsgBox("Vorzeitiger Thread-Abbruch bei " & Counter.ToString)
  End If
End Sub

Private Sub ThreadZiel()
  For i As Integer = 0 To 2000
    Thread.Sleep(10)
    Label1.BeginInvoke(New UpdateLabel(AddressOf LabelBearbeit), _
           i.ToString)
    Counter = i
  Next

  MsgBox("Normales Thread-Ende mit " & Counter.ToString)
End Sub

Private Sub LabelBearbeit(ByVal Wert As String)
  Label1.Text = Wert
End Sub

End Class

For i As Integer = 0 To StrArray.Length - 1
  If StrArray(i).Contains("A") And StrArray(i) <> "" Then
    StrArray(i) = StrArray(i).Replace("ABC", "")
    StrArray(i) = StrArray(i).Insert(0, "123")
  End If
Next

Dim Wert As String

For i As Integer = 0 To StrArray.Length - 1
  Wert = StrArray(i)
  If Wert.Contains("A") And Wert <> "" Then
    Wert = Wert.Replace("A", "")
    Wert = Wert.Insert(0, "123")
  End If
Next

Dim n As Integer = 10

For i As Integer = 1 To 3
  Dim Labl As Label = New Label

   Labl.Name = "Label" & i
   Labl.Text = "Label" & i
   Labl.Top = 100
   Labl.Left = n
   n += Labl.Width
   Controls.Add(Labl)
Next