如何使用c＃突出显示鼠标指针位置

Question

I need a simple mouse pointer highlighter in the form of a circle centered at the mouse pointer. Using Invalidate() in the below code causes rear circles along the path as flickers. They are hardly noticeable. Moreover, it doesn't draw the circle at the moment i rest the mouse.

What event should I consider to draw the circle at the position the mouse pointer is rested (tried other mouse events as well)?

Is there a way to refresh the drawing without using invalidate()?

 private void Form1_MouseMove(object sender, MouseEventArgs e)
    {

        SolidBrush myBrush = new SolidBrush(Color.Yellow);
        Graphics gg = this.CreateGraphics();
        Point p = new Point();
        p = e.Location;
        int radius = 10;
        float x = p.X - radius;
        float y = p.Y - radius;
        float width = 5 * radius;
        float height = 5 * radius;
        gg.FillEllipse(myBrush, x, y, width, height);
        gg.dispose();
        Invalidate();

    }

Answer 1

First turn on DoubleBuffered = true;

Then this should do:

private void Form1_MouseMove(object sender, MouseEventArgs e)
{
    Invalidate();
}

private void Form1_Paint(object sender, PaintEventArgs e)
{
    float radius = 10f;
    Point pt = PointToClient(Cursor.Position);
    e.Graphics.SmoothingMode = SmoothingMode.HighQuality;
    e.Graphics.FillEllipse(Brushes.Yellow, pt.X - radius, 
                           pt.Y - radius, radius * 2, radius * 2);

}

Since you are trying to highlight a spot on the background you may want to use a semi-transparent Color like this:

 using (SolidBrush brush = new SolidBrush(Color.FromArgb(160, Color.Yellow)))
     e.Graphics.FillEllipse(brush, pt.X - radius, pt.Y - radius, radius * 2, radius * 2);

You may want to play with other values for alpha than 160.