Base-64 char数组或字符串的无效长度（解码时）

Question

I'm getting error ' Invalid length for a Base-64 char array or string. '.
I've tried with two different encoded strings viz.:
1. ZGVudmVyZ29tZXMyMTEw which is decrypted correctly as: DENVERGOMES2110 , and
2. c2FkZGFtaHVzc2Fpbg== which gives error. The string is 'SADDAMHUSSAIN'.

I'm using ASP.net MVC 4. Here's my code:
Controller:

public string EncryptUsername(string userID, int status)
{
    string strResult = string.Empty;
    StudentRegistrationDAL dal = new StudentRegistrationDAL();
    strResult = dal.EncryptDecryptUsername(userID, status);
    return strResult;
}

DataAccessLayer.class:

public string EncryptDecryptUsername(string userID, int status)
{
    string encUsername = string.Empty;
     ReverseEngineerDAL encryptDecryptDAL = new ReverseEngineerDAL();
     if (status == 1)
     {
         encUsername = encryptDecryptDAL.EncodePasswordToBase64(userID);
     }
     else if (status == 2)
     {
         encUsername = encryptDecryptDAL.DecodeFrom64(userID).ToUpper();
     }
     return encUsername;
}

ReverseEngineerDAL.class:

public class ReverseEngineerDAL
{
    public string EncodePasswordToBase64(string password)
    {
        try
        {
            byte[] encData_byte = new byte[password.Length];
            encData_byte = System.Text.Encoding.UTF8.GetBytes(password);
            string encodedData = Convert.ToBase64String(encData_byte);
            return encodedData;
        }
        catch (Exception ex)
        {
            throw new Exception("Error in base64Encode" + ex.Message);
        }
    }

    public string DecodeFrom64(string encodedData)
    {
        System.Text.UTF8Encoding encoder = new System.Text.UTF8Encoding();
        System.Text.Decoder utf8Decode = encoder.GetDecoder();
        byte[] todecode_byte = Convert.FromBase64String(encodedData);
        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;
    }
}

I'm getting error at ' ReverseEngineerDAL.class ' in string DecodeFrom64(string encodedData) on line:

byte[] todecode_byte = Convert.FromBase64String(encodedData);

Can anyone help me in solving this error.? or spot the mistake in my code?
Any help would be appreciated. Thanks.

Answer 1

Just figured out that I was fetching my encrypted values wrongly.
Had a javascript split method which trimmed the == after my encrypted text.

My C# code was working fine. Just a little Googling and reading several posts on Stack helped me.

Here's my Jquery code to which I made minor changes.

        function GetParameterValues(param) {
        var url = window.location.href.slice(window.location.href.indexOf('?') + 1).split('&');
        for (var i = 0; i < url.length; i++) {
            /*var urlparam = url[i].split('=');
            if (urlparam[0] == param) {
            return urlparam[1];
            }*/
            var urlparam = url[0].substring(2, url[0].length);
            return urlparam;
        }
    }

The commented section was creating problem as it was trimming the =(equal) sign towards the end.

Manuel Zelenka 's comment gave me this hint.

I appreciate everyone's comments. And very big thanks to everyone.