asp+语法教程(五)asp+的服务器端编程控件篇

浏览：48日期：2022-12-23

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' 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"DHTMLFunction += " var numDays = MonthDays[CurrentDate.getMonth()];n"DHTMLFunction += " var firstDay = new Date(1999, 8, 1).getDay();n"DHTMLFunction += " for (var x=0; x<firstDay; x++)n"DHTMLFunction += " {n"DHTMLFunction += " calText = calText + '<td align=right width=23></td>'n"DHTMLFunction += " }n"DHTMLFunction += " for (var x=1; x<=numDays; x++) n"DHTMLFunction += " { n"DHTMLFunction += " if (CurrentDate.getDate() == x) n"DHTMLFunction += " { n"DHTMLFunction += " calText = calText + '<td align=right width=23>';n"DHTMLFunction += " calText = calText + '<font color=red><b><u>' + x + '</u></b></font>';n"DHTMLFunction += " calText = calText + '</td>';n"DHTMLFunction += " }n"DHTMLFunction += " else n"DHTMLFunction += " { n"DHTMLFunction += " calText = calText + '<td align=right width=23>';n"DHTMLFunction += " calText = calText + "<a href='javascript:drawcalendar("" + calname + "", "" + CurrentDate.getFullYear() + "/" + (CurrentDate.getMonth()+1) + "/" + x + "")'>" + x + "</a>";"DHTMLFunction += " calText = calText + '</td>';n"DHTMLFunction += " }n"DHTMLFunction += " if (((firstDay+x) % 7) == 0)n"DHTMLFunction += " {n"DHTMLFunction += " calText = calText + '</tr><tr>';n"DHTMLFunction += " }n"DHTMLFunction += " }n"DHTMLFunction += " calText = calText + '</tr>';"DHTMLFunction += " calText = calText + '</table></td></tr></table>';"DHTMLFunction += " var CalendarSpan = document.all(calname);"DHTMLFunction += " if (CalendarSpan != null)"DHTMLFunction += " CalendarSpan.innerHTML = calText;"DHTMLFunction += " var CalendarValue = document.all(calname + '_CurrentDate');"DHTMLFunction += " if (CalendarValue != null)"DHTMLFunction += " CalendarValue.value = '' + (CurrentDate.getMonth() + 1) + '/' + CurrentDate.getDate() + '/' + CurrentDate.getFullYear();"DHTMLFunction += " } n"DHTMLFunction += "</script>n"if (Page.Request.UserAgent.IndexOf("MSIE 5.5") != -1) Page.RegisterClientScriptBlock("ACME_CALENDAR_DHTML", DHTMLFunction); } protected void RenderDownLevel(HtmlTextWriter output) { // Output Calendar Header output.WriteLine("<table bgcolor=" + backColor + " border=0 height=190 valign=top><tr><td>"); output.WriteLine("<table bgcolor=" + backColor + " border=0 height=190 valign=top>"); output.WriteLine("<tr><td>"); output.WriteLine("<center>"); output.WriteLine(" <a href="javascript:" + Page.GetPostBackEventReference(this, "NavPrevMonth") + "">"); output.WriteLine("<img src=/quickstart/aspplus/images/left4.gif width=11 height=11 border=0></a>"); output.WriteLine(" <b>" + monthNames[currentDate.Month-1] + " " + Int32.Format(currentDate.Year, null) + "</b>"); output.WriteLine(" <a href="javascript:" + Page.GetPostBackEventReference(this, "NavNextMonth") + "">"); output.WriteLine("<IMG SRC=/quickstart/aspplus/images/right4.gif width=11 height=11 border=0></a>"); output.WriteLine("</center>"); output.WriteLine("</td></tr>"); output.WriteLine("<tr valign=top><td valign=top>"); output.WriteLine("<table border=1 bgcolor=" + foreColor + " height=160>"); output.WriteLine("<tr height=20>"); output.WriteLine(" <td align=right width=23> Sun </td>"); output.WriteLine(" <td align=right width=23> Mon </td>"); output.WriteLine(" <td align=right width=23> Tue </td>"); output.WriteLine(" <td align=right width=23> Wed </td>"); output.WriteLine(" <td align=right width=23> Thu </td>"); output.WriteLine(" <td align=right width=23> Fri </td>"); output.WriteLine(" <td align=right width=23> Sat </td>"); output.WriteLine("</tr>"); output.WriteLine("<tr>"); // Calculate how many days are in the month int numDays = DateTime.DaysInMonth(currentDate.Year, currentDate.Month); // Calculate what day of week the first day of the month is on int firstDay = new DateTime(currentDate.Year, currentDate.Month, 1).DayOfWeek; // Pre-Day Padding for (int x=0; x<firstDay; x++) { output.WriteLine("<td align=right width=23></td>"); } // Output each day for (int x=1; x<=numDays; x++) { if (currentDate.Day == x) { output.Write("<td align=right width=23>"); output.Write("<font color=red><b><u>" + Int32.Format(x, null) + "</u></b></font>"); output.WriteLine("</td>"); } else { output.Write("<td align=right width=23>"); output.Write("<a href="javascript:" + Page.GetPostBackEventReference(this, Int32.Format(x, null)) + "">"); output.Write(Int32.Format(x, null) + "</a>"); output.WriteLine("</td>"); } // PerPage row break as appropriate if (((firstDay+x) % 7) == 0) { output.WriteLine("</tr><tr>"); } } output.WriteLine("</tr>"); output.WriteLine("</table></td></tr></table></table>"); } public DateTime Date { get { return currentDate; } set { currentDate = value; } } public String BackColor { get { return backColor; } set { backColor = value; } } public String ForeColor { get { return foreColor; } set { foreColor = value; } } // Todo: We should eliminate the need for a control developer to do stub // implementations of the below standard IPostDataHandler Methods public bool LoadPostData(String postDataKey, NameValueCollection values) { String clientDate = values[UniqueID + "_CurrentDate"]; if (clientDate != null) currentDate = DateTime.Parse(clientDate); return false; } public void RaisePostDataChangedEvent() { } } } 生成服务器控件的文件 csc /t:library /r:System.Web.dll /r:System.dll /out:......binAcme.dll Acme.cs csc /t:library /out:......binWebMarket.dll WebMarket.cs 这个例子的演示在 http://tutorial.superexpert.com/quickstart/aspplus/samples/webforms/intro/intro7.aspx 这个日历的服务器控件可以同时支持高级和低级的浏览器，对于高级的浏览器，他在客户端生成DHTML 代码，DHTML 文档不需要和服务器进行交互！对于低级的浏览器，则生成标准的 HTML 3.2 的代码，这个时候需要和服务器的交互来处理浏览器客户端的用户操作注意：这个页面的代码的开发者在书写的过程中，开发者不需要关心客户浏览器是高级的还是低级的。日历控件自己会处理两种浏览器之间的差别下一讲，我们将要进入asp+ 操作数据库的章节，请大家随时留意我们的站点更新！

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