button1.TabStop = false;button1.FlatAppearance.BorderSize = 0;
button1.FlatAppearance.BorderColor = Color.FromArgb(0, 255, 255, 255); //設(shè)置邊框的顏色Transparent
button1.FlatAppearance.MouseOverBackColor = Color.FromArgb(0, 255, 255, 255); //設(shè)置鼠標(biāo)經(jīng)過(guò)時(shí)候的背景顏色Transparent
button1.FlatAppearance.MouseDownBackColor = Color.FromArgb(0, 255, 255, 255); //設(shè)置鼠標(biāo)按下時(shí)候的背景顏色Transparent

//鼠標(biāo)落下設(shè)置一張圖片
private void button1_MouseDown(object sender, MouseEventArgs e)
{
     this.button1.Image = Image.FromFile(@"../../images/close_click.png");
}

//鼠標(biāo)彈起恢復(fù)原來(lái)圖片
private void button1_MouseUp(object sender, MouseEventArgs e)
{
     this.button1.Image = Image.FromFile(@"../../images/close_default.png");
}

//響應(yīng)點(diǎn)擊事件
private void button1_Click(object sender, EventArgs e)
{
     MessageBox.Show("I'm normal button");
}

private void pictureBox2_MouseDown(object sender, MouseEventArgs e)
 {
      this.pictureBox2.Image = Image.FromFile(@"../../images/close_click.png");
}

private void pictureBox2_MouseUp(object sender, MouseEventArgs e)
{
     this.pictureBox2.Image = Image.FromFile(@"../../images/close_default.png");
}

private void pictureBox2_Click(object sender, EventArgs e)
{
      MessageBox.Show("I'm closed");
}