Показывать MessageBox в заданных координатах

Form2 form2 = new Form2();          
form2.DesktopLocation = new Point(значение по X,значение по Y);
form2.SetLabelText(текст_1,текст_2,...,текст_n);
form2.ShowDialog();

public void SetLabelText(String text_1,String text_2,...,String text_n)
{
    текст_1 = text_1;
    текст_2 = text_2;
    ...
    текст_n = text_n;
}

        public int yscreen = Screen.PrimaryScreen.Bounds.Height;
        public int xscreen = Screen.PrimaryScreen.Bounds.Width;
//много много кода...
   WorldSaver.Form4 f2 = new WorldSaver.Form4();
                f2.Owner = this;
                f2.DesktopLocation = new Point (rand.Next(1,xscreen),rand.Next(1,yscreen));
                f2.ShowDialog();
//
                                f2.DesktopLocation.X = xscreen;
                f2.DesktopLocation.Y = yscreen; // тоже не робят
//Location тоже не пашет

public int yscreen = Screen.PrimaryScreen.Bounds.Height;
public int xscreen = Screen.PrimaryScreen.Bounds.Width;
//много много кода...
WorldSaver.Form4 f2 = new WorldSaver.Form4();
f2.Owner = this;
f2.SetLocationXY(rand.Next(1,xscreen),rand.Next(1,yscreen));
f2.ShowDialog();

int x,y;
public void SetLocationXY(Int32 x_value,Int32 y_value)
{
    x = x_value;
    y = y_value;
}
void Form4Load(object sender, EventArgs e)
{
    this.Location = new Point(x,y);
}