Public Class Form2
    Inherits System.Windows.Forms.Form
#Region " Vom Windows Form Designer generierter Code "
    Public Sub New()
        MyBase.New()
        InitializeComponent()
    End Sub
    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
    Private components As System.ComponentModel.IContainer
    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()
        Me.TextBox1.Location = New System.Drawing.Point(16, 16)
        Me.TextBox1.Name = "TextBox1"
        Me.TextBox1.TabIndex = 0
        Me.TextBox1.Text = "TextBox1"
        Me.TextBox2.Location = New System.Drawing.Point(16, 40)
        Me.TextBox2.Name = "TextBox2"
        Me.TextBox2.TabIndex = 1
        Me.TextBox2.Text = "TextBox2"
        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
        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 = "Form2"
        Me.Text = "Form1"
        Me.ResumeLayout(False)
    End Sub
#End Region
    Sub DrawLines()
        Me.PictureBox1.Refresh()
        Dim gr As Graphics = Me.PictureBox1.CreateGraphics
        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)
        If Me.ActiveControl Is Me.TextBox1 Then
            gr.DrawLines(pr, New Point() {P1, P2})
        ElseIf Me.ActiveControl Is Me.TextBox2 Then
            gr.DrawLines(ps, New Point() {P3, P4})
        End If
    End Sub
    Private Sub TextBoxes_GotFocus(ByVal sender As Object, ByVal e As _
      System.EventArgs) Handles TextBox1.GotFocus, TextBox2.GotFocus
        sender.SelectAll()
        Me.DrawLines()
    End Sub
End Class