asp+语法介绍(五)服务器端编程控件
使用定制的服务器控件
在asp+中提供了45个已经做好了的服务器控件，我们可以将他们象黑盒子一样的使用。除此以外，开发者还可以使用任何第三方开发的服务器控件
在下面的例子中，我们要用到一个通过<acme:calendar runat=server>标签声明的组件，请注意，在文件的第一行必须使用<% Register %> 来声明 "Acme Xml "标签的的前缀"Acme".在asp+ 文件中，将会使用这个命名的服务器控件的类的实例。
<%@ Register TagPrefix="Acme" Namespace="Acme" %>
<html>
<head>
<link rel="stylesheet"href="intro.css">
</head>
<script language="VB" runat=server>
Sub SubmitBtn_Click(Sender As Object, E As EventArgs)
Message.Text = "Hi " & Name.Text & ", you selected: " & Category.SelectedItem.Text & " on: " & MyCal.Date
End Sub
</script>
<body>
<center>
<form action="intro7.aspx" method="post" runat="server">
<asp:adrotator AdvertisementFile="ads.xml" BorderColor="black" BorderWidth=1 runat="server"/>
<h3> Name: <asp:textbox id="Name" runat="server"/>
Category: <asp:dropdownlist id="Category" runat=server>
<asp:listitem >psychology</asp:listitem>
<asp:listitem >business</asp:listitem>
<asp:listitem >popular_comp</asp:listitem>
</asp:dropdownlist>
<asp:button type=submit text="Lookup" OnClick="SubmitBtn_Click" runat="server"/>
<p>
<Acme:Calendar id="MyCal" runat=server/>
<p>
<asp:label id="Message" runat="server"/>
</form>
</center>
</body>
</html>
声明Acme 的 文件
using System;
using System.Web;
using System.Web.UI;
using System.Collections;
namespace Acme
{
public class Calendar : Control, IPostBackEventHandler, IPostBackDataHandler
{
private String[] monthNames = new String[12];
private DateTime currentDate = DateTime.Now;
private String backColor = "#dcdcdc";
private String foreColor = "#eeeeee";
protected override void Init()
{
// Todo: We should remove the need to call this
Page.RegisterRequiresPostBack(this);
Page.RegisterPostBackScript();
currentDate = DateTime.Now;
// Todo: Hack needed because COOL doesn't support array initializers yet
monthNames[0] = "January";
monthNames[1] = "February";
monthNames[2] = "March";
monthNames[3] = "April";
monthNames[4] = "May";
monthNames[5] = "June";
monthNames[6] = "July";
monthNames[7] = "August";
monthNames[8] = "September";
monthNames[9] = "October";
monthNames[10] = "November";
monthNames[11] = "December";
}
protected override void LoadState(Object viewState)
{
// If we've done a post-back, the old date will be available to us
if (null != viewState)
{
currentDate = DateTime.Parse((String) viewState);
}
}
public void RaisePostBackEvent(String eventArgument)
{
//Page.Response.Write("RaisePostBackEvent Called!!!");
if (eventArgument == null)
{
return;
}
// Keep track of old date (for event firing purposes)
DateTime oldDate = currentDate;
// Todo: We should have post-back take two arguments: eventname and eventarguments
if (String.Compare("NavNextMonth", eventArgument, true) == 0)
{
currentDate = currentDate.AddMonths(1);
}
else if (String.Compare("NavPrevMonth", eventArgument, true) == 0)
{
currentDate = currentDate.AddMonths(-1);
}
else
{
int daySelected = Int32.Parse(eventArgument);
currentDate = new DateTime(currentDate.Year, currentDate.Month, daySelected);
}
}
protected override Object SaveState()
{
// Save CurrentDate out as view state for postback scenarios
return currentDate.ToString();
}
protected override void Render(HtmlTextWriter output)
{
//Response.Write(Page.Request.UserAgent);
if (Page.Request.UserAgent.IndexOf("MSIE 5.5") != -1)
RenderUpLevel(output);
else
RenderDownLevel(output);
}
protected void RenderUpLevel(HtmlTextWriter output)
{
output.WriteLine("<input name='" + UniqueID + "_CurrentDate' id='" + UniqueID + "_CurrentDate' type=hidden>");
output.WriteLine("<span id='" + UniqueID + "'></span>");
output.WriteLine("<script language=jscript>drawcalendar('" + UniqueID + "', '" + Int32.Format(currentDate.Year, null) + "/" + Int32.Format(currentDate.Month, null) + "/" + Int32.Format(currentDate.Day, null) + "');</script>");
}
protected override void PreRender()
{
String DHTMLFunction = "";
DHTMLFunction += "<script language='JavaScript'> \n";
DHTMLFunction += " function drawcalendar(calname, newDate) \n";
DHTMLFunction += " { \n";
DHTMLFunction += " var CurrentDate = new Date(newDate);\n";
DHTMLFunction += " var MonthArray = new Array('January', 'February', 'March', 'April', 'May', 'June', 'July', 'August', 'September', 'October', 'November', 'December');\n";
DHTMLFunction += " var MonthDays = new Array(31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31);\n";
DHTMLFunction += " var calText;\n";
DHTMLFunction += " calText = '<table bgcolor=#dcdcdc border=0 height=190 valign=top>';\n";
DHTMLFunction += " calText = calText + '<tr><td>';\n";
DHTMLFunction += " calText = calText + '<center>';\n";
DHTMLFunction += " calText = calText + \"<a href='javascript:drawcalendar(\\\"\" + calname + \"\\\", \\\"\" + CurrentDate.getFullYear() + \"/\" + CurrentDate.getMonth() + \"/\" + CurrentDate.getDate() + \"\\\")'>\";\n";
DHTMLFunction += " calText = calText + '<img src=/quickstart/aspplus/images/left4.gif width=11 height=11 border=0></a>';\n";
DHTMLFunction += " calText = calText + ' <b>' + MonthArray[CurrentDate.getMonth()] + ' ' + CurrentDate.getFullYear() + '</b>';\n";
DHTMLFunction += " calText = calText + \" <a href='javascript:drawcalendar(\\\"\" + calname + \"\\\", \\\"\" + CurrentDate.getFullYear() + \"/\" + (CurrentDate.getMonth() + 2) + \"/\" + CurrentDate.getDate() + \"\\\")'>\";\n";
DHTMLFunction += " calText = calText + '<IMG SRC=/quickstart/aspplus/images/right4.gif width=11 height=11 border=0></a>';\n";
DHTMLFunction += " calText = calText + '</center>';\n";
DHTMLFunction += " calText = calText + '</td></tr>';\n";
DHTMLFunction += " calText = calText + '<tr valign=top><td valign=top>';\n";
DHTMLFunction += " calText = calText + '<table border=1 bgcolor=#eeeeee height=160>';\n";
DHTMLFunction += " calText = calText + '<tr height=20>';\n";
DHTMLFunction += " calText = calText + ' <td align=right width=23> Sun </td>';\n";
DHTMLFunction += " calText = calText + ' <td align=right width=23> Mon </td>';\n";
DHTMLFunction += " calText = calText + ' <td align=right width=23> Tue </td>';\n";
DHTMLFunction += " calText = calText + ' <td align=right width=23> Wed </td>';\n";
DHTMLFunction += " calText = calText + ' <td align=right width=23> Thu </td>';\n";
DHTMLFunction += " calText = calText + ' <td align=right width=23> Fri </td>';\n";
DHTMLFunction += " calText = calText + ' <td align=right width=23> Sat </td>';\n";
DHTMLFunction += " calText = calText + '</tr>';\n";
DHTMLFunction += " calText = calText + '<tr>';\n";
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