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

ps:帖子借鉴：http://www.vbforums.com/showthread.php?s=&threadid=287324