C#完全透明的按钮可与背景完美结合

private void SetBtnStyle(Button btn)  
{  
    btn.FlatStyle = FlatStyle.Flat;//样式  
    btn.ForeColor = Color.Transparent;//前景  
    btn.BackColor = Color.Transparent;//去背景  
    btn.FlatAppearance.BorderSize = 0;//去边线  
    btn.FlatAppearance.MouseOverBackColor = Color.Transparent;//鼠标经过  
    btn.FlatAppearance.MouseDownBackColor = Color.Transparent;//鼠标按下  

}

private void btn_MouseHover(object sender, EventArgs e)  
{  
    Button btn = sender as Button;  
    btn.FlatAppearance.BorderSize = 1;  
}   

private void btn_MouseLeave(object sender, EventArgs e)  
{  
    Button btn = sender as Button;  
    btn.FlatAppearance.BorderSize = 0;  
}