C# Draw when window is loaded

I want to draw some ellipses when the window is loaded without clicking anything, how can I do it? My code is the following :

        int kerX = random.Next(10,281);
        int kerY = random.Next(10,281);
        mrPainter.FillEllipse(Brushes.Black, kerX + 10, kerY 开发者_运维问答+ 10, 20, 20);
        mrPainter.FillEllipse(blue,65,65,20,20);
        mrPainter.FillEllipse(red, 205, 65, 20, 20);
        mrPainter.FillEllipse(yellow, 135, 215, 20, 20);

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Assuming that your are using WinForms, simply insert the code in the FormLoaded event of your main form.