如何替换颜色

Question

窗体背景是很多种颜色组成的一副图片
当我按下某个按纽时  要把窗体背景里的黑色换成黄色 请问如何实现

Answer 1

this.BackColor = Color.Yellow;

Answer 2

        private void Form1_Load(object sender, EventArgs e)
        {
            this.BackgroundImage = Image.FromFile(@"c:\a.bmp");
        }        private void button1_Click(object sender, EventArgs e)
        {           
            Bitmap bm = new Bitmap(this.BackgroundImage);
            for (int i = 0; i < bm.Height; i++)
            {
                for (int j = 0; j < bm.Width; j++)
                {
                    if (bm.GetPixel(j, i).R == byte.MinValue &&
                        bm.GetPixel(j, i).G == byte.MinValue &&
                        bm.GetPixel(j, i).B == byte.MinValue)
                    {
                        bm.SetPixel(j, i, Color.Yellow);
                    }
                }                
            }
            this.BackgroundImage = (Image)bm;
}