C# 保存网络图片至本地项目中

1、获取项目根目录 System.AppDomain.CurrentDomain.BaseDirectory

以下为把图片转成流保存成文件

#region 保存web图片到本地
        /// <summary>
        /// 保存web图片到本地
        /// </summary>
        /// <param name="imgUrl">web图片路径</param>
        /// <param name="path">保存路径</param>
        /// <param name="fileName">保存文件名</param>
        /// <returns></returns>
        public static string SaveImageFromWeb(string imgUrl, string path, string fileName)
        {
            if (path.Equals(""))
                throw new Exception("未指定保存文件的路径");
            string imgName = imgUrl.ToString().Substring(imgUrl.ToString().LastIndexOf("/") + 1);
            string defaultType = ".jpg";
            string[] imgTypes = new string[] { ".jpg", ".jpeg", ".png", ".gif", ".bmp" };
            string imgType = imgUrl.ToString().Substring(imgUrl.ToString().LastIndexOf("."));
            string imgPath = "";
            foreach (string it in imgTypes)
            {
                if (imgType.ToLower().Equals(it))
                    break;
                if (it.Equals(".bmp"))
                    imgType = defaultType;
            }

            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(imgUrl);
            request.UserAgent = "Mozilla/6.0 (MSIE 6.0; Windows NT 5.1; Natas.Robot)";
            request.Timeout = 3000;

            WebResponse response = request.GetResponse();
            Stream stream = response.GetResponseStream();

            if (response.ContentType.ToLower().StartsWith("image/"))
            {
                byte[] arrayByte = new byte[1024];
                int imgLong = (int)response.ContentLength;
                int l = 0;

                if (fileName == "")
                    fileName = imgName;

                FileStream fso = new FileStream(path + fileName + imgType, FileMode.Create);
                while (l < imgLong)
                {
                    int i = stream.Read(arrayByte, 0, 1024);
                    fso.Write(arrayByte, 0, i);
                    l += i;
                }

                fso.Close();
                stream.Close();
                response.Close();
                imgPath = fileName + imgType;
                return imgPath;
            }
            else
            {
                return "";
            }
        }
        #endregion

注：以上代码适用于获取网络图片保存时会到参数无效时。

System.Drawing.Image.FromStream(ms) 这里会抛出异常，上网查阅资料说是透明度的问题不兼容，所以可以考虑直接用文件的形式保存下来，然后在获取对应的图片