C# 字符串、文件、图片等与Base64的相互转化

一、字符串转Base64编码相互转化

(1)字符串=》Base64

public static string EncodeBase64(string code_type, string code)
    {
        string encode = "";
        byte[] bytes = Encoding.GetEncoding(code_type).GetBytes(code);
        try
        {
            encode = Convert.ToBase64String(bytes);
        }
        catch
        {
            encode = code;
        }
        return encode;
    }

调用方法：
var val1 = EncodeBase64(“utf-8”, “你好啊”);

(2)Base64转字符串

public static string DecodeBase64(string code_type, string code)
    {
        string decode = "";
        byte[] bytes = Convert.FromBase64String(code);
        try
        {
            decode = Encoding.GetEncoding(code_type).GetString(bytes);
        }
        catch
        {
            decode = code;
        }
        return decode;
    }

调用方法：
var val2 = DecodeBase64(“utf-8”, “PHRyPjx0ZD7kvaDlpb3llYo8L3RkPjwvdHI+”);

二、图片对象与Base64的相互转换

（１）图片转为base64编码的字符串

#region 图片转为base64编码的字符串
public string ImgToBase64String(string Imagefilename)
{
try
{
Bitmap bmp = new Bitmap(Imagefilename);
 
MemoryStream ms = new MemoryStream();
bmp.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
byte[] arr = new byte[ms.Length];
ms.Position = 0;
ms.Read(arr, 0, (int)ms.Length);
ms.Close();
return Convert.ToBase64String(arr);
}
catch (Exception ex)
{
return null;
}
}
#endregion

（２）base64编码的字符串转为图片

#region base64编码的字符串转为图片
public void Base64StringToImage(string strbase64)
{
 
try
{
byte[] arr = Convert.FromBase64String(strbase64);
MemoryStream ms = new MemoryStream(arr);
System.Drawing.Image img = System.Drawing.Image.FromStream(ms);
 
 
string ls_path = Server.MapPath(@"images\camera\" + ls_imageNameCamera + ".jpg");
 
img.Save(ls_path, System.Drawing.Imaging.ImageFormat.Jpeg);
 
//System.Drawing.Image img = System.Drawing.Image.FromStream(ms);
//img.Save("ImgName.jpg", System.Drawing.Imaging.ImageFormat.Jpeg);
//img.Save("ImgName.bmp", ImageFormat.Bmp);
//img.Save("ImgName.gif", ImageFormat.Gif);
//img.Save(@"images\ImgName.png", ImageFormat.Png);
 
Session["ImageNameCamera"] = ls_imageNameCamera;
}
catch (Exception ex)
{
 
}
}
#endregion
 

三、文件与base64相互转换(文件为任意格式)

（１）文件转base64字符串,文件可以为任意格式,代码如下:

        /// <summary>
        /// 文件转base64
        /// </summary>
        /// <returns>base64字符串</returns>
        public string FileToBase64String(string File)
        {
            FileStream fsForRead = new FileStream(File, FileMode.Open);//文件路径
            string base64Str = "";
            try
            {
                //读写指针移到距开头10个字节处
                fsForRead.Seek(0, SeekOrigin.Begin);
                byte[] bs = new byte[fsForRead.Length];
                int log = Convert.ToInt32(fsForRead.Length);
                //从文件中读取10个字节放到数组bs中
                fsForRead.Read(bs, 0, log);
                base64Str = Convert.ToBase64String(bs);
                return base64Str;
            }
            catch (Exception ex)
            {
                Console.Write(ex.Message);
                Console.ReadLine();
                return base64Str;
            }
            finally
            {
                fsForRead.Close();
            }
        }
 

（２）base64字符串转文件,文件可以为任意格式,代码如下:

        /// <summary>
        /// Base64字符串转文件并保存
        /// </summary>
        /// <param name="base64String">base64字符串</param>
        /// <param name="fileName">保存的文件名</param>
        /// <returns>是否转换并保存成功</returns>
        public bool Base64StringToFile(string base64String, string fileName)
        {
            bool opResult = false;
            try
            {
                string strDate = DateTime.Now.ToString("yyyyMMdd");
                string fileFullPath = "C:\\WGQ_GROUP_DSMS.SysAdmin\\UpFile\\" + strDate;//文件保存路径
                if (!Directory.Exists(fileFullPath))
                {
                    Directory.CreateDirectory(fileFullPath);
                }
 
                string strbase64 = base64String.Trim().Substring(base64String.IndexOf(",") + 1);   //将‘，’以前的多余字符串删除
                MemoryStream stream = new MemoryStream(Convert.FromBase64String(strbase64));
                FileStream fs = new FileStream(fileFullPath + "\\" + fileName, FileMode.OpenOrCreate, FileAccess.Write);
                byte[] b = stream.ToArray();
                fs.Write(b, 0, b.Length);
                fs.Close();
 
                opResult = true;
            }
            catch (Exception e)
            {
                logger.Error("异常类型: \t" + e.GetType());
                logger.Error("异常描述：\t" + e.Message);
                logger.Error("异常方法：\t" + e.TargetSite);
                logger.Error("异常堆栈：\t" + e.StackTrace);
            }
            return opResult;
        }