string p = @"<xml>
    <ToUserName><![CDATA[{0}]]></ToUserName>
    <FromUserName><![CDATA[{1}]]></FromUserName>
    <CreateTime>1412135923</CreateTime>
    <MsgType><![CDATA[image]]></MsgType>
    <PicUrl><![CDATA[{2}]]></PicUrl>
    <MsgId>6065077606992462276</MsgId>
    <MediaId><![CDATA[PqRRUPLhMc27EG5F4cCtTozBsin7SY8kPRRuAF-CwPl5MzR5ewE5oji0FhGTDl6_]]></MediaId>
</xml>";
Response.Write(string.Format(p,WeiXinMsgInfo.ToUser,WeiXinMsgInfo.OpenId,codepic));
这样写会不成功吗