Base64的解码和编码

把UTF8的string转化为base64的string：

public string base64Encode(string data)
{
try
{
byte[] encData_byte = new byte[data.Length];
encData_byte = System.Text.Encoding.UTF8.GetBytes(data);
string encodedData = Convert.ToBase64String(encData_byte);
return encodedData;
}
catch(Exception e)
{
throw new Exception("Error in base64Encode" + e.Message);
}
}

把Base64的string转化为UTF8的string：

public string base64Decode(string data)
{
try
{
System.Text.UTF8Encoding encoder = new System.Text.UTF8Encoding();
System.Text.Decoder utf8Decode = encoder.GetDecoder();

byte[] todecode_byte = Convert.FromBase64String(data);
int charCount = utf8Decode.GetCharCount(todecode_byte, 0, todecode_byte.Length);
char[] decoded_char = new char[charCount];
utf8Decode.GetChars(todecode_byte, 0, todecode_byte.Length, decoded_char, 0);
string result = new String(decoded_char);
return result;
}
catch(Exception e)
{
throw new Exception("Error in base64Decode" + e.Message);
}
}

最主要的是使用System.Convert