1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:

private void pbBewegen(PictureBox pb)
        {
            InitializeComponent();
            Random r = new Random();
           int hoehe = r.Next(1, 240);
           for (int i = 5; i < 245; i++)
           { pb.Location = new Point(i, hoehe);
           Thread.Sleep(100);
       }
        }

//Konstouktor:
public Form1()
        {
            InitializeComponent();
            pbBewegen(pictureBox1);
        }					

1:
2:
3:
4:
5:
6:
7:
8:
9:
10:
11:
12:
13:
14:
15:
16:
17:
18:
19:
20:
21:
22:
23:

public Form1()
        {
            InitializeComponent();
            ;
            this.Invalidated += new InvalidateEventHandler(Form1_Invalidated);
        }

        void Form1_Invalidated(object sender, InvalidateEventArgs e)
        {
            Thread t = new Thread(new ThreadStart(pbBewegen));
            t.Start();
        }

        private void pbBewegen()
        {
            
            Random r = new Random();
           int hoehe = r.Next(1, 240);
           for (int i = 5; i < 245; i++)
           { pictureBox1.Location = new Point(i, hoehe);
           Thread.Sleep(100);
       }
        }					

1:

CheckForIllegalCrossThreadCalls = false;