Public Class Form1
 
    ' Maus-Koordinaten
    Dim nStartPos As Point
    Dim nDragPos As Point
 
    Dim contr As Control
    Dim smallc As Control
    Dim x As Integer
 
 
    Private Sub contr_MouseMove(ByVal sender As Object, ByVal e As  _
      System.Windows.Forms.MouseEventArgs)
        If e.Button = Windows.Forms.MouseButtons.Left Then
            ' aktuelle Mausposition bezogen auf den Desktop ermitteln
            Dim nCurPos As Point = contr.PointToScreen(New Point(e.X, e.Y))
 
            ' Neue Position des Controls berechnen
            Dim nNewPos As New Point(nStartPos.X + nCurPos.X - nDragPos.X, _
              nStartPos.Y + nCurPos.Y - nDragPos.Y)
 
            ' Neue Koordianten prüfen und sicherstellen, dass das Control
            ' nicht aus den sichtbaren Bereich der Form verschoben wird
            With nNewPos
                If .X < Me.ClientRectangle.Left Then .X = Me.ClientRectangle.Left
                If .X + contr.Width > Me.ClientRectangle.Right Then
                    .X = Me.ClientRectangle.Right - contr.Width
                End If
                If .Y < Me.ClientRectangle.Top Then .Y = Me.ClientRectangle.Top
                If .Y + contr.Height > Me.ClientRectangle.Bottom Then
                    .Y = Me.ClientRectangle.Bottom - contr.Height
                End If
            End With
 
            ' Control an neuen Position verschieben
            contr.Location = nNewPos
        End If
    End Sub
 
    Private Sub Form1_Load(ByVal sender As Object, ByVal e As System.EventArgs) _
      Handles Me.Load
        Dim txt As New TextBox
        x = 0
        txt.Text = "Hallo Welt"
        txt.Left = 10
        txt.Width = 100
        txt.Height = 20
        txt.Top = 20
        txt.Visible = True
        txt.Name = "txt" & x.ToString
        x = x + 1
 
        AddHandler txt.MouseDown, AddressOf contr_MouseDown
        AddHandler txt.MouseMove, AddressOf contr_MouseMove
 
        Me.Controls.Add(txt)
 
 
    End Sub
 
    Private Sub contr_MouseDown(ByVal sender As Object, ByVal e As  _
      System.Windows.Forms.MouseEventArgs)
 
        ' Feststellen das die Linke Maustaste gedrückt ist
        If e.Button = Windows.Forms.MouseButtons.Left Then
            ' Finden welches Control es war
            For Each smallc As Control In Me.Controls
                ' Richtige Control gefunden 
                If smallc.Focused Then
                    contr = smallc
                    ' aktuelle Position des Controls und der Maus merken
                    nStartPos = contr.Location
                    nDragPos = contr.PointToScreen(New Point(e.X, e.Y))
                End If
            Next
        End If
    End Sub
End Class