.NET解密得到UnionID

由于微信没有提供.NET的解码示例代码，自己搜索写了一个，下面的代码是可用的

var decryptBytes = Convert.FromBase64String(encrypdata);
            var keyBytes = Convert.FromBase64String(sessionkey);
            var ivBytes = Convert.FromBase64String(iv);

            var aes = new AesCryptoServiceProvider
            {
                Key = keyBytes,
                IV = ivBytes,
                Mode = CipherMode.CBC,
                Padding = PaddingMode.PKCS7
            };
            var outputBytes = aes.CreateDecryptor().TransformFinalBlock(decryptBytes, 0, decryptBytes.Length);
            string decryptResult = Encoding.UTF8.GetString(outputBytes);