Dim TextBox() As TextBox
    Private Sub Fill()
        Me.SuspendLayout()
        Dim padding As Integer = 3
        Dim left As Integer = 10
        For a As Integer = 0 To 10
            ReDim Preserve TextBox(a)
            TextBox(a) = New System.Windows.Forms.TextBox
            TextBox(a).Name = a.ToString '// Name setzen
            TextBox(a).Size = New Size(80, 20)
            TextBox(a).Location = (New Point(left, ((TextBox(a).Size.Height + _
              padding) * a) + 10))
            Me.TabPage1.Controls.Add(TextBox(a))
        Next
        Me.ResumeLayout()
    End Sub
    Private Function GetTextBox(ByVal name As String, ByVal tabPage As TabPage) _
      As TextBox
        For Each t As TextBox In tabPage.Controls
            If TypeOf (t) Is TextBox AndAlso name = t.Name Then
                Return t '// TextBox gefunden
            End If
        Next
        Return Nothing
    End Function
    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles Button3.Click
        Me.GetTextBox("4", Me.TabPage1).Focus()
        Me.GetTextBox("4", Me.TabPage1).Text = "Hallo Welt"
    End Sub