您的位置:首页 > 其它

网易邮箱添加附件功能原理浅析

2009-11-27 22:53 387 查看
个人觉得网易邮箱的添加附件功能是比较酷的,这两天网上网下研究了下。有些心得写出来,免得遗忘。

一切起源于type为file的input,这是没话可多说的(这个东西很神秘)。为什么网易页面上却没有看见这个东西?看下面:

<html>
<head>
<title>上传控件演示</title>
</head>
<body>
<input type="file" id="f1" style="display:none;" />
<input type="button" onclick="f1.click();" value="文件浏览" />
</body>
</html>

正如上面看到的:看不见它,却也能够打开文件浏览框。

做成网易效果了吗?

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="test.aspx.cs" Inherits="mytest_test" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<title>上传控件演示</title>
</head>
<body>
<form id="form1" runat="server">
<input type="file" name="f1" id="f1" runat="server" />
<input type="button" value="浏览文件" name="cbtn" onclick="f1.click();" />
<asp:Button ID="submit" runat="server" OnClick="Button1_Click1" Text="保存" />
</form>
</body>
</html>
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

public partial class mytest_test : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void Button1_Click1(object sender, EventArgs e)
{
Response.Write("上传文件数目:"+Request.Files.Count.ToString());
}
}

如上:点击f1后点击submit,有一个文件上传到服务端。点击cbtn后点击submit,连提交动作都没有。

在客户端看来:点击f1后或点击cbtn后页面表现没有区别。

网上的解释:浏览器的安全机制。

上传文件要点:(1)必须要有鼠标点击;(2)必须点击在上传控件的浏览按钮上。

类似163的实现:

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="test.aspx.cs" Inherits="mytest_test" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
<title>163上传</title>
<style type="text/css">
a.addfile {
background-image:url(http://p.mail.163.com/js31style/lib/0703131650/163blue/f1.gif);
background-repeat:no-repeat;
background-position:-915px -17px;
display:block;
float:left;
height:20px;
margin-top:-1px;
position:relative;
text-decoration:none;
top:0pt;
width:80px;
}

input.addfile {
cursor:pointer !important;
height:18px;
left:-13px;
filter:alpha(opacity=0);
position:absolute;
top:5px;
width:1px;
z-index: -1;
}
</style>
</head>
<body>
<form id="form1" runat="server">
<div>
<a id="container1" class="addfile">
<input id="file_0" name="file_0" type="file" class="addfile" runat="server" />
</a>
</div>
<asp:Button ID="Button1" runat="server" Text="Button" OnClick="Button1_Click" />
</form>
</body>
</html>
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

public partial class mytest_test : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void Button1_Click(object sender, EventArgs e)
{
Response.Write("上传文件数目:" + Request.Files.Count.ToString());
}
}

要点:(1)把上传控件放在a标签中;(2)上传控件透明(不是display:none);(3)a标签衬背景。

接下来,做批量的效果:

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="test.aspx.cs" Inherits="mytest_test" %>

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head id="Head1" runat="server">
<title>163上传</title>
<style type="text/css">
a.addfile {
background-image:url(http://p.mail.163.com/js31style/lib/0703131650/163blue/f1.gif);
background-repeat:no-repeat;
background-position:-915px -17px;
display:block;
float:left;
height:20px;
margin-top:-1px;
position:relative;
text-decoration:none;
top:0pt;
width:80px;
}

input.addfile {
cursor:pointer !important;
height:18px;
left:-13px;
filter:alpha(opacity=0);
position:absolute;
top:5px;
width:1px;
z-index: -1;
}
img.addfile {
background-image:url(http://p.mail.163.com/js31style/lib/0703131650/163blue/f1.gif);
background-repeat:no-repeat;
background-position:-802px -36px;
width:13px;
height:13px;
}
</style>

<script type="text/javascript">
window.$ = document.getElementById;
var fileNumber = 0;
function createnew()
{
var c_a = $('container1');// 找到上传控件的a容器
var c_div = $('container2');// 放置文件的容器
var fileCtr = c_a.firstChild;// 上传控件

var subDiv = document.createElement("div");// 将放置到c_div中的容器
var span1 = document.createElement("span");// 上传的文件
span1.innerText = fileCtr.value;

var img2 = document.createElement("img");// 删除图片按钮
img2.className = "addfile";
img2.onclick = function(){this.parentNode.parentNode.removeChild(this.parentNode)}

subDiv.appendChild(span1);
subDiv.appendChild(img2);
subDiv.appendChild(fileCtr);

c_div.appendChild(subDiv);

fileNumber++;

var newFileCtr = document.createElement("input");
newFileCtr.type = "file";
newFileCtr.className = "addfile";
newFileCtr.runat = "server";
newFileCtr.name = "file_"+fileNumber;
newFileCtr.onchange = createnew;
while(c_a.firstChild)
{
c_a.removeChild(c_a.firstChild);
}

c_a.appendChild(newFileCtr);
}
</script>

</head>
<body>
<form id="form1" runat="server">
<div>
<a id="container1" class="addfile">
<input id="File1" name="file_0" type="file" class="addfile" onchange="createnew();" runat="server" />
</a>
</div>
<div id="container2" style="position:relative; float:left; ">
</div>
<asp:Button ID="Button1" runat="server" Text="Button" OnClick="Button1_Click" />
</form>
</body>
</html>

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

public partial class mytest_test : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void Button1_Click(object sender, EventArgs e)
{
string s = "";
for (int i = 0; i < Request.Files.Count; i++)
{
s += Request.Files[i].FileName + "<br/>";
}
Response.Write(s);
}
}

差不多实现了163的添加附件效果,但未判断相同文件上传情况。

要点:上传控件的onchange事件。这个事件在选择文件之后。在这个事件中移走旧的上传控件,创建新的上传控件。创建上传控件时一定别忘了name和runat这两个属性。
内容来自用户分享和网络整理,不保证内容的准确性,如有侵权内容,可联系管理员处理 点击这里给我发消息
标签: