如果您出于某种原因想要将文件转换为 base-64 字符串.就像如果你想通过互联网传递它等等......你可以这样做

If you want for some reason to convert your file to base-64 string. Like if you want to pass it via internet, etc... you can do this

Byte[] bytes = File.ReadAllBytes("path");
String file = Convert.ToBase64String(bytes);

相应地，读回文件:

Byte[] bytes = Convert.FromBase64String(b64Str);
File.WriteAllBytes(path, bytes);