新信息到来提醒的解决方案

大家都知道要在一个Asp.net应用程序中，实现即时信息提醒比较麻烦，在Asp.net不能使用Timer的方式来完成帮每个用户的定时访问数据库的操作，只能利用javascript来的SetInterval方法来完成用户的定时刷新页面操作，但存在的问题是页面一直在不断的刷新。在CSDN上的一篇文章（http://dev.csdn.net/article/63/63930.shtm）给了一个很好的解决方案。利用javascript + WebService ，利用javascript去访问WebService。唯的麻烦之处在于要自己写SOAP消息完成访问访问WebService。下面就来看看具体的实现过程。

一、创建一个WebService，在我的WebService中有这样(HasNewMessage,原型是public string HasNewMessage(string userID,out int mailCount,out int pendingCount))一个方法，用IE访问WebService调用这个方法会有下面的一串SOAP请求消息格式.

POST /WebService/NewsService.asmx HTTP/1.1

Host: 192.168.7.108

Content-Type: text/xml; charset=utf-8

Content-Length: length

SOAPAction: "http://tempuri.org/HasNewMessage"

<?xml version="1.0" encoding="utf-8"?>

<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">

<soap:Body>

<userID>string</userID>

</HasNewMessage>

</soap:Body>

</soap:Envelope>

我们就可以根据它来编写我们的SOAP消息了。WebService将会以下面的格式返回我们的请求。

HTTP/1.1 200 OK

Content-Type: text/xml; charset=utf-8

Content-Length: length

<?xml version="1.0" encoding="utf-8"?>

<soap:Envelope xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:soap="http://schemas.xmlsoap.org/soap/envelope/">

<soap:Body>

<HasNewMessageResult>string</HasNewMessageResult>

</HasNewMessageResponse>

</soap:Body>

</soap:Envelope>

在这个函数中，我有三个输出，其实mailCount,pendingCount是输出参数.在程序中我可以根据这个格式来分解出我们所获得的输出。

二、用javascript访问WebService

function HasNewMail()

{

var userID = "3011";

var myService = "http://192.168.7.108/WebService/NewsService.asmx" ;

var myMethod = "http://tempuri.org/HasNewMessage";

var requestHttp = new ActiveXObject("Microsoft.XMLHTTP");

var requestBody = "";

requestBody = requestBody + "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n" ;

requestBody = requestBody + "<soap:Envelope ";

requestBody = requestBody + "xmlns:xsi=\"http://www.w3.org/2001/XMLSchema-instance\" ";

requestBody = requestBody + "xmlns:xsd=\"http://www.w3.org/2001/XMLSchema\" " ;

requestBody = requestBody + "xmlns:soap=\"http://schemas.xmlsoap.org/soap/envelope/\">\n" ;

requestBody = requestBody + " <soap:Body>\n" ;

requestBody = requestBody + " <HasNewMessage xmlns=\"http://tempuri.org/\">\n" ;

requestBody = requestBody + " <userID>" + userID + "</userID>\n";

requestBody = requestBody + " </HasNewMessage>\n";

requestBody = requestBody + " </soap:Body>\n";

requestBody = requestBody + "</soap:Envelope>";

requestHttp.Open("POST",myService,false);

requestHttp.SetRequestHeader("Content-Type","text/xml;charset=gb2312");

requestHttp.SetRequestHeader("SOAPAction",myMethod);

requestHttp.Send(requestBody);

var result = requestHttp.ResponseXML;

var pos1 = result .xml.indexOf("<HasNewMessageResult>");

var pos2 = result .xml.indexOf("</HasNewMessageResult>");

var len = pos2 - pos1 - ("<HasNewMessageResult>").length;

var userName = result.xml.substr(pos1 + ("<HasNewMessageResult>").length , len);

pos1 = result.xml.indexOf("<mailCount>");

pos2 = result.xml.indexOf("</mailCount>");

len = pos2 - pos1 - ("<mailCount>").length;

var mailCount = result.xml.substr(pos1 + ("<mailCount>").length , len);

pos1 = result.xml.indexOf("<pendingCount>");

pos2 = result.xml.indexOf("</pendingCount>");

len = pos2 - pos1 - ("<pendingCount>").length;

var pendingCount= result.xml.substr(pos1 + ("<pendingCount>").length , len);

var allCount = parseInt(mailCount) + parseInt(pendingCount);

//弹出显示

if(allCount > 0)

PopUpNotify(userName,allCount,mailCount,pendingCount)

}

这个函数首先创建一个ActiveXObj利用它来完成对WebService的访问。然后根据上面介绍的格式创建SOAP消息体，与WebService交互。最后对所得到的WebService返回消息进行分解，得出所需的数据。

三、Pop窗口的弹出。Pop窗口的弹出有几种方法，好像也有这方面的专门控件，由于用javascript来完成，选用层的移动应用或PopupObject来实现，它可以让显示信息自下而上移动，但在测试过程中发现直接用层会被框架遮住。所以选用PopupObject，但存在一个问题就是用户不能控制这个PopupObject的关闭，它的关闭方式是在父窗体获得焦点以后就会自动关闭，在层实体的”self.close()”，不能很好的工作，它会弹出确认关闭窗口，随后自己就关闭了。以下是弹出函数和层实体(复制别人用层写出的弹出消息的一个层实体，把它作为PopupObject的innerHTML也能很的显示，真好！)。

var oPopup = window.createPopup();

function PopUpNotify(userName,allCount,mailCount,pendigCount)

{

var oPopupBody = oPopup.document.body;

var HTMLBody = eMeng.innerHTML;

HTMLBody = HTMLBody.replace(/userName/g,userName);

HTMLBody = HTMLBody.replace(/allCount/g,allCount);

HTMLBody = HTMLBody.replace(/mailCount/g,mailCount);

HTMLBody = HTMLBody.replace(/pendingCount/g,pendigCount);

oPopupBody.innerHTML = HTMLBody;

oPopup.show(screen.availWidth ,screen.Height - 145,180,116);

var realHeight = oPopupBody.scrollHeight;

oPopup.hide();

// Shows the actual popup object with correct height.

oPopup.show(screen.availWidth,screen.Height - 145,180,116);

window.setTimeout("oPopup.hide()",5000);

}

层实体如下:

<TABLE style="BORDER-TOP: #ffffff 1px solid; BORDER-LEFT: #ffffff 1px solid" cellSpacing="0"

cellPadding="0" width="100%" bgColor="#cfdef4" border="0" ID="Table8">

<TBODY>

<TR>

<TD style="FONT-WEIGHT: normal; FONT-SIZE: 9pt; BACKGROUND-IMAGE: url(msgboximages/top.gif); COLOR: #1f336b; PADDING-TOP: 4px"

vAlign=center width="100%">系统提示：</TD>

</TR>

<TR>

<DIV style="BORDER-RIGHT: #b9c9ef 1px solid; PADDING-RIGHT: 13px; BORDER-TOP: #728eb8 1px solid; PADDING-LEFT: 13px; FONT-SIZE: 9pt; PADDING-BOTTOM: 13px; BORDER-LEFT: #728eb8 1px solid; WIDTH: 100%; COLOR: #1f336b; PADDING-TOP: 18px; BORDER-BOTTOM: #b9c9ef 1px solid; HEIGHT: 100%"> <b>userName</b>

您共有<B><FONT color="red">allCount</FONT></B>条新消息</FONT><BR>

其中：<BR>

新邮件有 <FONT color="red"><B>mailCount</B></FONT> 封。</a><BR>

新事件有 <FONT color="red"><B>pendingCount </B></FONT>条.</a><BR>

</DIV>

</TD>

</TR>

</TBODY></TABLE>

</DIV>

这样就可以实现访问WebService和显示相关信息了。当然了，定时访问还要设置一个函数setInterval

function VisitService()

{

HasNewMail();

window.setInterval("HasNewMail()",60000);

}

在页面加载事件中运行这个函数就能实现定时访问了。

直接用层来实现Popup效果也是一种不错的方法，这里给别人写的代码。上面的层实体也从这个例子中得到的。

var divTop,divLeft,divWidth,divHeight,docHeight,docWidth,objTimer,i = 0;

var divBody = "";

function SaveDIVInnerHTML()

{

divBody = document.getElementById("eMeng").innerHTML;

}

function getMsg(allCount,mailCount,pendingCount)

{

try{

divTop = parseInt(document.getElementById("eMeng").style.top,10)

divLeft = parseInt(document.getElementById("eMeng").style.left,10)

divHeight = parseInt(document.getElementById("eMeng").offsetHeight,10)

divWidth = parseInt(document.getElementById("eMeng").offsetWidth,10)

docWidth = document.body.clientWidth;

docHeight = document.body.clientHeight;

document.getElementById("eMeng").style.top = parseInt(document.body.scrollTop,10) + docHeight + 10;// divHeight

document.getElementById("eMeng").style.left = parseInt(document.body.scrollLeft,10) + docWidth - divWidth

document.getElementById("eMeng").style.visibility="visible";

alert(divBody);

document.getElementById("eMeng").innerHTML = document.getElementById("eMeng").innerHTML.replace(/allCount/g,allCount);

document.getElementById("eMeng").innerHTML = document.getElementById("eMeng").innerHTML.replace(/mailCount/g,mailCount);

document.getElementById("eMeng").innerHTML = document.getElementById("eMeng").innerHTML.replace(/pendingCount/g,pendingCount);

objTimer = window.setInterval("moveDiv()",10)

}

catch(e){}

}

function moveDiv()

{

try

{

if(parseInt(document.getElementById("eMeng").style.top,10) <= (docHeight - divHeight + parseInt(document.body.scrollTop,10)))

{

window.clearInterval(objTimer)

objTimer = window.setInterval("resizeDiv()",1)

}

divTop = parseInt(document.getElementById("eMeng").style.top,10)

document.getElementById("eMeng").style.top = divTop - 1

}

catch(e){}

}

function resizeDiv()

{

i+=1

if(i>500) closeDiv()

try{

divHeight = parseInt(document.getElementById("eMeng").offsetHeight,10)

divWidth = parseInt(document.getElementById("eMeng").offsetWidth,10)

docWidth = document.body.clientWidth;

docHeight = document.body.clientHeight;

document.getElementById("eMeng").style.top = docHeight - divHeight + parseInt(document.body.scrollTop,10)

document.getElementById("eMeng").style.left = docWidth - divWidth + parseInt(document.body.scrollLeft,10)

}

catch(e){}

}

function closeDiv()

{

document.getElementById('eMeng').style.visibility='hidden';

if(objTimer) window.clearInterval(objTimer)

document.getElementById("eMeng").innerHTML = divBody;

}