/// <summary>
/// 生成请求时的签名
/// </summary>
/// <param name="sPara">请求给支付宝的参数数组</param>
/// <param name="signType">签名方式</param>
/// <param name="key">交易安全校验码</param>
/// <param name="code">字符编码格式</param>
/// <returns>签名结果</returns>
private static string BuildRequestMysign(Dictionary <string, string> sPara, string signType, string key, Encoding code)
{
//把数组所有元素，按照“参数=参数值”的模式用“&”字符拼接成字符串
string prestr = AlipayCore.CreateLinkString(sPara);
//把最终的字符串签名，获得签名结果
string mysign = "";
switch (signType)
{
case "MD5":
mysign = AlipayMD5.Sign(prestr, key, code);
break;
default:
mysign = "";
break;
}
return(mysign);
}