asp.net中的“按需打印”(打印你需要打印的部分) 实现代码

过程很简单：

首先在asp.net页面中设定开始打印和结束打印的标记，为了确保该标记不在网页浏览时显示，我们采用"<!-- HTML注释 -->"的方式。比如：<!--startprint-->和<!--endprint-->。

接着写相关的JavaScript代码，具体代码见后。

如果不想打印按钮也被打印出来，注意将打印按钮包含在<!--startprint-->和<!--endprint-->之外。

相关代码：


代码如下:

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="AppealPrint.aspx.cs" Inherits="Appeal.AppealPrint"

MasterPageFile="MasterPage.master" Title="诉求打印" %>

<asp:Content ID="Content1" ContentPlaceHolderID="CphNavigation" runat="server">
</asp:Content>
<asp:Content ID="Content2" ContentPlaceHolderID="CphContent" runat="server">
<!--startprint-->
<style type="text/css">
body,table{
    font-size:12px;
}
table{
    table-layout:fixed;
    empty-cells:show;
    border-collapse: collapse;
    margin:0 auto;
}
td{
    height:20px;
}
h1,h2,h3{
    font-size:12px;
    margin:0;
    padding:0;
}

table{
    border:1px solid #cad9ea;
    color:#666;
}
table th{
    height:30px;
}
table td,table th{
    border:1px solid #cad9ea;
    padding:0 1em 0;
}
table tr{
    background-color:#f5fafe;
}
</style>
   <table class="border" cellspacing="0" cellpadding="2" style="margin: 0px auto; width: 98%;border:1px solid;border-collapse:collapse;" id="TabBtnPrint">
    <tbody>
        <tr align="center">
            <td class="title"><strong>诉 求 信 息</strong></td>
        </tr>
        <tr>
            <td style="height: 25px">
            <table cellspacing="1" cellpadding="2" style="margin: 0px auto; width: 100%;border-collapse:collapse;">
                <tbody>
                    <tr class="tdbg">
                         <td width="30%" align="right" nowrap="nowrap">诉求主题：</td>
                         <td colspan="3">
                             <asp:Label ID="lblEditTitle" runat="server" Text="Label"></asp:Label>
                         </td>
                    </tr>
                    <tr class="tdbg">
                        <td align="right" width="30%" nowrap="nowrap">诉求类型：</td>
                        <td  colspan="3">
                              <asp:Label ID="lblAppealCategory" runat="server" Text=""/>
                        </td>
                    </tr>
                    <tr class="tdbg">
                        <td align="right" width="30%" nowrap="nowrap">诉求当前状态：</td>
                        <td colspan="3">
                              <asp:Label ID="LblStatus" runat="server" Text="Label"/>
                        </td>
                    </tr>
                    <tr class="tdbg">
                        <td align="right" style="width: 30%" nowrap="nowrap">诉求性质：</td>
                        <td style="width: 15%"><asp:Label ID="lblAppealNature" runat="server" Text="Label"/></td>
                        <td align="right" style="width: 25%" nowrap="nowrap">被投诉人姓名：</td>
                        <td style="width: 30%"><asp:Label ID="lblBeAppealName" runat="server" Text="Label"/></td>
                    </tr>

<tr class="tdbg">
                        <td align="right" style="width: 30%" nowrap="nowrap">被投诉人地址：</td>
                        <td style="width: 15%"><asp:Label ID="lblBeAppealAddress" runat="server" Text="Label"/></td>
                        <td align="right" style="width: 25%" nowrap="nowrap">投诉人：</td>
                        <td style="width: 30%"><asp:Label ID="lblUserName" runat="server" Text="Label"/></td>
                    </tr>

<tr class="tdbg">
                        <td align="right" style="width: 30%" nowrap="nowrap">诉求信息是否保密：</td>
                        <td style="width: 15%"><asp:Label ID="lblIsSecret" runat="server" Text="Label"/></td>
                        <td align="right" style="width: 25%" nowrap="nowrap">管理员是否同意公开：</td>
                        <td style="width: 30%" align="right"><asp:Label ID="lblAdminIsPublic" runat="server" Text="Label"/></td>
                    </tr>

<tr class="tdbg">
                        <td align="right" style="width: 30%" nowrap="nowrap">浏览数：</td>
                        <td style="width: 15%"><asp:Label ID="lblHits" runat="server" Text="Label"/></td>
                        <td align="right" style="width: 25%" nowrap="nowrap">回复数：</td>
                        <td style="width: 30%"><asp:Label ID="lblReply" runat="server" Text="Label"/></td>
                    </tr>

<tr class="tdbg">
                        <td align="right" style="width: 30%" nowrap="nowrap">归档：</td>
                        <td style="width: 15%"><asp:Label ID="lblCategory" runat="server" Text=""/></td>
                        <td align="right" style="width: 25%" nowrap="nowrap">诉求提交时间：</td>
                        <td style="width: 30%"><asp:Label ID="lblCreateTime" runat="server" Text="Label"/></td>
                    </tr>

<tr class="tdbg">
                        <td align="right" style="width: 30%" nowrap="nowrap">诉求所在地域：</td>
                        <td colspan="3"><asp:Label ID="lblRegion" runat="server" Text=""></asp:Label></td>
                    </tr>
                    <tr class="tdbg">
                        <td colspan="4"><asp:Label ID="Label2" runat="server" Text=""/></td>
                    </tr>
                    <tr class="tdbg">
                        <td colspan="4" align="left" valign="top" nowrap="nowrap">诉求内容：</td>
                    </tr>
                    <tr class="tdbg">
                        <td colspan="4" align="left" valign="top">
                            <pe:ExtendedLiteral ID="LtrEditContent" runat="server" HtmlEncode="false"/>
                        </td>
                    </tr>
                </tbody>
            </table>
            </td>
        </tr>
    </tbody>
</table>
<!--endprint-->
   <br />
    <div id="divBtnPrint" style="text-align:center">
        <input id="BtnPrint" type="button" value="打 印…" onclick="doPrint();" />
    </div>
    <br />
 <script type="text/javascript">

<!--

function doPrint(){
        bdhtml = window.document.body.innerHTML;
        sprnstr = "<!--startprint-->";
        eprnstr = "<!--endprint-->";
        prnhtml = bdhtml.substr(bdhtml.indexOf(sprnstr) + 17);
        prnhtml = prnhtml.substring(0, prnhtml.indexOf(eprnstr));
        window.document.body.innerHTML =  prnhtml;
        var obj = window.document.body;
        doZoom(obj, 18); //放大打印
        window.print();
    }

function doZoom(artibody, size) {
        if (!artibody)
        {
          return;
        }
          setChildNodesByCurrentNode(artibody,size);
    }

function setChildNodesByCurrentNode(node,size) {
        for(var i=0; i < node.childNodes.length; i++) {
            var artibodyChild = node.childNodes[i];
            if (artibodyChild.nodeType == 1) {
                artibodyChild.className="";
                artibodyChild.style.fontSize = size + 'px';
                artibodyChild.style.fontFamily = '仿宋_GB2312,宋体,"Times New Roman",Georgia,serif';
                artibodyChild.style.fontWeight = 900;
                if(artibodyChild.childNodes.length>0) {
                    setChildNodesByCurrentNode(artibodyChild,size);
                }
            }
         }
      }

-->

</script>
</asp:Content>

观察上面代码可以看出，打印时，window.document.body.innerHTML 被重新赋值成设定需要打印的网页部分的代码（这里是 prnhtml），然后通过递归方式调用setChildNodesByCurrentNode(artibody,size)更改相关子节点的样式，以达到全部更换相关字体大小及样式设置的目的。