Public Class Form1
    Inherits System.Windows.Forms.Form
 
#Region " Vom Windows Form Designer generierter Code "
 
    Public Sub New()
        MyBase.New()
 
        ' Dieser Aufruf ist für den Windows Form-Designer erforderlich.
        InitializeComponent()
 
        ' Initialisierungen nach dem Aufruf InitializeComponent() hinzufügen
 
    End Sub
 
    ' Die Form überschreibt den Löschvorgang der Basisklasse, um Komponenten zu 
    ' bereinigen.
    Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
        If disposing Then
            If Not (components Is Nothing) Then
                components.Dispose()
            End If
        End If
        MyBase.Dispose(disposing)
    End Sub
 
    ' Für Windows Form-Designer erforderlich
    Private components As System.ComponentModel.IContainer
 
    'HINWEIS: Die folgende Prozedur ist für den Windows Form-Designer 
    ' erforderlich
    'Sie kann mit dem Windows Form-Designer modifiziert werden.
    'Verwenden Sie nicht den Code-Editor zur Bearbeitung.
	Friend WithEvents TextBox1 As System.Windows.Forms.TextBox
	Friend WithEvents TextBox2 As System.Windows.Forms.TextBox
	Friend WithEvents PictureBox1 As System.Windows.Forms.PictureBox
	<System.Diagnostics.DebuggerStepThrough()> Private Sub InitializeComponent()
		Me.TextBox1 = New System.Windows.Forms.TextBox
		Me.TextBox2 = New System.Windows.Forms.TextBox
		Me.PictureBox1 = New System.Windows.Forms.PictureBox
		Me.SuspendLayout()
		'
		'TextBox1
		'
		Me.TextBox1.Location = New System.Drawing.Point(16, 16)
		Me.TextBox1.Name = "TextBox1"
		Me.TextBox1.TabIndex = 0
		Me.TextBox1.Text = "TextBox1"
		'
		'TextBox2
		'
		Me.TextBox2.Location = New System.Drawing.Point(16, 40)
		Me.TextBox2.Name = "TextBox2"
		Me.TextBox2.TabIndex = 1
		Me.TextBox2.Text = "TextBox2"
		'
		'PictureBox1
		'
		Me.PictureBox1.Location = New System.Drawing.Point(128, 16)
		Me.PictureBox1.Name = "PictureBox1"
		Me.PictureBox1.Size = New System.Drawing.Size(100, 100)
		Me.PictureBox1.TabIndex = 3
		Me.PictureBox1.TabStop = False
		'
		'Form1
		'
		Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
		Me.ClientSize = New System.Drawing.Size(248, 134)
		Me.Controls.Add(Me.PictureBox1)
		Me.Controls.Add(Me.TextBox2)
		Me.Controls.Add(Me.TextBox1)
		Me.Name = "Form1"
		Me.Text = "Form1"
		Me.ResumeLayout(False)
 
	End Sub
 
#End Region
 
	Private Sub PictureBox1_Paint(ByVal sender As Object, ByVal e As _
  System.Windows.Forms.PaintEventArgs) Handles PictureBox1.Paint
		Dim gr As Graphics = e.Graphics
		Dim ps As New Pen(Color.Black, 2)
		Dim pr As New Pen(Color.Red, 2)
		Dim P1 As New Point(0, 0)
		Dim P2 As New Point(0, 100)
		Dim P3 As New Point(100, 0)
		Dim P4 As New Point(100, 100)
 
		gr.DrawLines(ps, New Point() {P1, P2})
		gr.DrawLines(ps, New Point() {P3, P4})
 
		If (Me.TextBox1.Focus = True) Then
			gr.DrawLines(pr, New Point() {P1, P2})
		ElseIf (Me.TextBox2.Focus = True) Then
			gr.DrawLines(pr, New Point() {P3, P4})
		End If
	End Sub
 
	Private Sub TextBox_Enter(ByVal sender As Object, ByVal e As System.EventArgs) _
  Handles TextBox1.Enter, TextBox2.Enter
		sender.SelectAll()
		Me.PictureBox1.Refresh()
	End Sub
 
	Private Sub TextBox_Leave(ByVal sender As Object, ByVal e As System.EventArgs) _
  Handles TextBox1.Leave, TextBox2.Leave
		Me.PictureBox1.Refresh()
	End Sub
End Class