C# ICON和Image互转

1.ICON转Image

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

2.Image转ICON

     /// <summary>
        /// 转换Image为Icon
        /// </summary>
        /// <param name="image">要转换为图标的Image对象</param>
        /// <param name="nullTonull">当image为null时是否返回null。false则抛空引用异常</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))
                {
                    //写图标头部
                    bin.Write((short)0);           //0-1保留
                    bin.Write((short)1);           //2-3文件类型。1=图标, 2=光标
                    bin.Write((short)1);           //4-5图像数量（图标可以包含多个图像）

                    bin.Write((byte)image.Width);  //6图标宽度
                    bin.Write((byte)image.Height); //7图标高度
                    bin.Write((byte)0);            //8颜色数（若像素位深>=8，填0。这是显然的，达到8bpp的颜色数最少是256，byte不够表示）
                    bin.Write((byte)0);            //9保留。必须为0
                    bin.Write((short)0);           //10-11调色板
                    bin.Write((short)32);          //12-13位深
                    bin.Write((int)msImg.Length);  //14-17位图数据大小
                    bin.Write(22);                 //18-21位图数据起始字节

                    //写图像数据
                    bin.Write(msImg.ToArray());

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