form中2个pictureBox控件
在启动调试后 怎么只让其中一个显示
让另一个点击按钮再出来

private bool bool_a_b = false;
private bool bool_a_b_c = false;
        private void button1_Click(object sender, EventArgs e)
        {
            if (bool_a_b == false && bool_a_b_c == false)
            {
                pictureBox1.Visible = true;
            }
            else

                if (bool_a_b == false && bool_a_b_c == true)
                {
                    pictureBox1.Visible = true;
                }
                else
                    if (bool_a_b == true && bool_a_b_c == true)
                    {
                        pictureBox1.Visible = false;
                    }
             }
我想点击出现 在点击又消失  要怎么解决