这篇博客主要是一个动态加载用户控件的实例,页面效果是当用户点击按钮时,出现日历控件(用户自定义控件,包括每个月的1日出现“发工资”的提示),对日历进行操作时,不影响整个页面(无刷新),当用户再次点击按钮时,用户控件卸载。以前我的一个日历的实例中也实现了这个效果,但是那时使用的是整体用户控件加载,并且不卸载功能,当用户点击按钮时,出现的日历出现和消失都是采用Visible方法,这无疑加重了页面的负担,今天学习到了这种方法,记录下来,供日后回顾。
     首先我们先来布置页面:
    1.在网站下添加新项用户控件,默认其页面名:WebUserControl.ascx
    2.在WebUserControl.ascx中添加一个日历控件,按照自己喜欢的样式改变其外观。
    这里我想说明两个Calendar控件的属性,让我们一起来重温Calendar控件,首先Calendar控件默认可以选择日期,可以使用SelectionMode属性修改这个选择操作,这个属性的值可以是Day(允许在日历中单击某个日期)、DayWeek(允许在日历中单击某个日期,同时可以单击星期旁边的箭头,选择整个星期)、DayWeekMonth(可以选择日期或星期,日历右上角的箭头允许选择整个月)、none(用户不能做任何操作)。接着:day属性的一个有用的功能是,可以把Day属性的IsSelectable设置为false,关闭选择某个日期或日期范围的选项。这个功能在实际开发中,可能会用到,代码如下:
if(e.Day.Date<DateTime.Now)
    e.Day.IsSelectable=false;
    3.编写每个月1日时日历出现的“发工资”的提示,代码如下:
InBlock.gif 1using System;
InBlock.gif 2using System.Collections;
InBlock.gif 3using System.Configuration;
InBlock.gif 4using System.Data;
InBlock.gif 5using System.Linq;
InBlock.gif 6using System.Web;
InBlock.gif 7using System.Web.Security;
InBlock.gif 8using System.Web.UI;
InBlock.gif 9using System.Web.UI.HtmlControls;
InBlock.gif10using System.Web.UI.WebControls;
InBlock.gif11using System.Web.UI.WebControls.WebParts;
InBlock.gif12using System.Xml.Linq;
InBlock.gif13
InBlock.gif14public partial class WebUserControl : System.Web.UI.UserControl
InBlock.gif15{
InBlock.gif16        protected void Page_Load(object sender, EventArgs e)
InBlock.gif17        {
InBlock.gif18
InBlock.gif19        }
InBlock.gif20        //DayRender:日历中显示的每一天都会运行该方法。
InBlock.gif21        protected void Calendar1_DayRender(object sender, DayRenderEventArgs e)
InBlock.gif22        {    
InBlock.gif23                //单元格的垂直对齐方式为top
InBlock.gif24                e.Cell.VerticalAlign = VerticalAlign.Top;
InBlock.gif25                if (e.Day.DayNumberText == "1")
InBlock.gif26                {
InBlock.gif27                        e.Cell.Controls.Add(new LiteralControl ("<p>发工资</p>"));
InBlock.gif28                        e.Cell.BorderColor = System.Drawing.Color.Black;
InBlock.gif29                        e.Cell.BorderWidth = 1;
InBlock.gif30                        e.Cell.BorderStyle = BorderStyle.Double;
InBlock.gif31                        e.Cell.BackColor = System.Drawing.Color.LightGray;
InBlock.gif32                }
InBlock.gif33        }
InBlock.gif34}
         4.新建一个AJAX窗口,命名为:DynamicLoadControl.aspx,在页面中放置一个Updatepanel1。
         5.在Updatepanel1中放入一个Button1,text=“…”(18行)。
         6. 在Updatepanel1中放入一个html的hidden控件,将其改为服务器控件,id改为:Dynamic_UserControl_Hidden1(17行)
页面布局介绍,下面我们来看一下DynamicLoadControl.aspx的客户端代码
1<head runat="server">
2        <title>无标题页</title>
3        <script type="text/javascript">    
4            function pageLoad() {
5            }
6        
7        </script>
8</head>
9<body>
10        <form id="form1" runat="server">
11        <div>
12        
13                <asp:ScriptManager ID="ScriptManager1" runat="server">
14                </asp:ScriptManager>
15                <asp:UpdatePanel ID="UpdatePanel1" runat="server" UpdateMode="Conditional">
16                        <ContentTemplate>
17                                <input ID="Dynamic_UserControl_Hidden1" type="hidden" runat="server" />
18                                <asp:Button ID="Button1" runat="server" Text="…" onclick="Button1_Click" />                                
19                        </ContentTemplate>
20                        <Triggers>
21                                <asp:AsyncPostBackTrigger ControlID="Button1" EventName="Click" />
22                        </Triggers>
23                </asp:UpdatePanel>
24        </div>
25        </form>
26</body>
27</html>
下面是cs代码,
InBlock.gif 1using System;
InBlock.gif 2using System.Collections;
InBlock.gif 3using System.Configuration;
InBlock.gif 4using System.Data;
InBlock.gif 5using System.Linq;
InBlock.gif 6using System.Web;
InBlock.gif 7using System.Web.Security;
InBlock.gif 8using System.Web.UI;
InBlock.gif 9using System.Web.UI.HtmlControls;
InBlock.gif10using System.Web.UI.WebControls;
InBlock.gif11using System.Web.UI.WebControls.WebParts;
InBlock.gif12using System.Xml.Linq;
InBlock.gif13
InBlock.gif14public partial class DynamicLoadControl : System.Web.UI.Page
InBlock.gif15{
InBlock.gif16        protected void Page_Load(object sender, EventArgs e)
InBlock.gif17        {
InBlock.gif18            
InBlock.gif19        }
InBlock.gif20        //这个方法先于page_load之前执行,也在控件初始化前执行
InBlock.gif21        protected void Page_Init(object sender, EventArgs e)
InBlock.gif22        {
InBlock.gif23                //从送来的参数中,判断用户控件是否已经加载,"Dynamic_UserControl_Hidden1"是个标志,
InBlock.gif24                //为true时,代表用户控件存在,初次加载页面时,表示是false,故没有用户控件出现在网页上
InBlock.gif25                if (Request.Params["Dynamic_UserControl_Hidden1"] == " true")
InBlock.gif26                        LoadDynamicUserControl();
InBlock.gif27
InBlock.gif28        }
InBlock.gif29        //点击按钮出现用户自定义控件
InBlock.gif30        protected void Button1_Click(object sender, EventArgs e)
InBlock.gif31        {
InBlock.gif32                //当用户自定义控件(标志为true)存在时,就移除到自定义控件,同时标志改为false。
InBlock.gif33                if (Request.Params["Dynamic_UserControl_Hidden1"] == "true")
InBlock.gif34                {
InBlock.gif35                        UpdatePanel1.ContentTemplateContainer.Controls.Remove(UpdatePanel1.ContentTemplateContainer.FindControl("WebUserControl1"));
InBlock.gif36                        HtmlInputHidden hidden = (HtmlInputHidden)UpdatePanel1.ContentTemplateContainer.FindControl("Dynamic_UserControl_Hidden1");
InBlock.gif37                        hidden.Value = "false";
InBlock.gif38
InBlock.gif39                }
InBlock.gif40                        //否则就加载用户自定义控件
InBlock.gif41                else
InBlock.gif42                        LoadDynamicUserControl();
InBlock.gif43        }
InBlock.gif44        //加载用户自定义控件
InBlock.gif45        private void LoadDynamicUserControl()
InBlock.gif46        {
InBlock.gif47                //当Updatepanel中没有用户控件时
InBlock.gif48                if (UpdatePanel1.ContentTemplateContainer.FindControl("WebUserControl1") == null)
InBlock.gif49                {
InBlock.gif50                        //根据指定的WebUserControl.ascx路径加载控件WebUserControl1
InBlock.gif51                        Control c = LoadControl("WebUserControl.ascx");
InBlock.gif52                        c.ID = "WebUserControl1";
InBlock.gif53                        //找到标志将其值改为true
InBlock.gif54                        HtmlInputHidden hidden =(HtmlInputHidden ) UpdatePanel1.ContentTemplateContainer.FindControl("Dynamic_UserControl_Hidden1");
InBlock.gif55                        hidden.Value = "true";
InBlock.gif56                        //在Updatepanel中加入用户控件
InBlock.gif57                        UpdatePanel1.ContentTemplateContainer.Controls.Add(c);            
InBlock.gif58                }
InBlock.gif59        }
InBlock.gif60        
InBlock.gif61}