this.StartPosition = FormStartPosition.Manual;
this.Location = new Point(SystemInformation.WorkingArea.Width - this.Width, SystemInformation.WorkingArea.Height - this.Height);
右下角
private void Form1_Load(object sender, EventArgs e)
{
this.Left = Screen.PrimaryScreen.WorkingArea.Width - this.Width;
this.Top = 0;
}