c# | base64图片转文件

        public string Base64StringToFile(string base64String, string fileName)
        {
            //文件后缀
            string suffix = "";
            try
            {
                //文件保存路径
                string fileFullPath = @"C:\Users\wenjingzhi\Desktop\MyBlog\UploadPictures";
                //如果没有文件夹,则创建
                if (!Directory.Exists(fileFullPath))
                {
                    Directory.CreateDirectory(fileFullPath);
                }
                //获取文件后缀
                string i = base64String.Trim().Substring(0, base64String.IndexOf(",") + 1);
                suffix = i.Substring(i.IndexOf("/") + 1, i.IndexOf(";") - i.IndexOf("/") - 1);
                //将,以前的多余字符串删除
                string strbase64 = base64String.Trim().Substring(base64String.IndexOf(",") + 1);
                //将指定的字符串（它将二进制数据编码为 Base64 数字）转换为等效的 8 位无符号整数数组
                MemoryStream stream = new MemoryStream(Convert.FromBase64String(strbase64));
                //文件读写
                FileStream fs = new FileStream(fileFullPath + "\\" + fileName + "." + suffix, FileMode.OpenOrCreate, FileAccess.Write);
                //将流写入数组
                byte[] b = stream.ToArray();
                fs.Write(b, 0, b.Length);
                fs.Close();
            }
            catch (Exception e)
            {
                System.Diagnostics.Trace.WriteLine("异常类型: \t" + e.GetType());
                System.Diagnostics.Trace.WriteLine("异常描述：\t" + e.Message);
                System.Diagnostics.Trace.WriteLine("异常方法：\t" + e.TargetSite);
                System.Diagnostics.Trace.WriteLine("异常堆栈：\t" + e.StackTrace);
            }
            return fileName + "." + suffix;
        }