C# ICON和Image互轉

1.ICON轉Image

Icon icon = Icon.ExtractAssociatedIcon(@"D:\XXXX\VSLogo.ico");
MemoryStream mStream = new MemoryStream();
icon.Save(mStream);
Image image = Image.FromStream(mStream);

2.Image轉ICON

     /// <summary>
        /// 轉換Image為Icon
        /// </summary>
        /// <param name="image">要轉換為圖標的Image對象</param>
        /// <param name="nullTonull">當image為null時是否返回null。false則拋空引用異常</param>
        /// <exception cref="ArgumentNullException" />
        /// <returns></returns>
        public static Icon ConvertToIcon(Image image, bool nullTonull = false)
        {
            if (image == null)
            {
                if (nullTonull)
                {
                    return null;
                }
                throw new ArgumentNullException("Image is null");
            }

            using (MemoryStream msImg = new MemoryStream(), msIco = new MemoryStream())
            {
                image.Save(msImg, ImageFormat.Png);

                using (var bin = new BinaryWriter(msIco))
                {
                    //寫圖標頭部
                    bin.Write((short)0);           //0-1保留
                    bin.Write((short)1);           //2-3文件類型。1=圖標, 2=光標
                    bin.Write((short)1);           //4-5圖像數量（圖標可以包含多個圖像）

                    bin.Write((byte)image.Width);  //6圖標寬度
                    bin.Write((byte)image.Height); //7圖標高度
                    bin.Write((byte)0);            //8顏色數（若像素位深>=8，填0。這是顯然的，達到8bpp的顏色數最少是256，byte不夠表示）
                    bin.Write((byte)0);            //9保留。必須為0
                    bin.Write((short)0);           //10-11調色板
                    bin.Write((short)32);          //12-13位深
                    bin.Write((int)msImg.Length);  //14-17位圖數據大小
                    bin.Write(22);                 //18-21位圖數據起始字節

                    //寫圖像數據
                    bin.Write(msImg.ToArray());

                    bin.Flush();
                    bin.Seek(0, SeekOrigin.Begin);
                    return new Icon(msIco);
                }
            }
        }