参数按照ASCII码从小到大排序

public static void requestPay()
{
Dictionary<string, string> dics = new Dictionary<string, string>();
dics.Add("amount", amount);
dics.Add("callback_url", callback_url);
dics.Add("goodsname", goodsname);
dics.Add("merchno", merchno);
dics.Add("notify_url", notify_url);
dics.Add("ordno", ordno);
dics.Add("organno", organno);
dics.Add("version", version);
dics.Add("paytype", paytype);

getParamSrc(dics);
}

public static String getParamSrc(Dictionary<string, string> paramsMap)
{
var vDic = (from objDic in paramsMap orderby objDic.Key ascending select objDic);
StringBuilder str = new StringBuilder();
foreach (KeyValuePair<string, string> kv in vDic)
{
string pkey = kv.Key;
string pvalue = kv.Value;
str.Append(pkey + "=" + pvalue + "&");
}

String result = str.ToString().Substring(0, str.ToString().Length - 1);
return result;
}