ASP.NET Tutorial/Custom Controls/Action — различия между версиями

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Версия 15:30, 26 мая 2010

Exposing Events from a User Control

File: Control.ascx
<%@ Control Language="C#" ClassName="TabStrip" %>
<%@ Import Namespace="System.Collections.Generic" %>
<script runat="server">
    public event EventHandler TabClick;
    public int SelectedIndex
    {
        get { return dlstTabStrip.SelectedIndex; }
    }
    void Page_Load()
    {
        if (!Page.IsPostBack)
        {
            List<string> tabs = new List<string>();
            tabs.Add("A");
            tabs.Add("B");
            tabs.Add("C");
            dlstTabStrip.DataSource = tabs;
            dlstTabStrip.DataBind();
            dlstTabStrip.SelectedIndex = 0;
        }
    }
    protected void dlstTabStrip_SelectedIndexChanged(object sender, EventArgs e)
    {
        if (TabClick != null)
            TabClick(this, EventArgs.Empty);
    }
</script>
<asp:DataList
    id="dlstTabStrip"
    RepeatDirection="Horizontal"
    OnSelectedIndexChanged="dlstTabStrip_SelectedIndexChanged"
    CssClass="tabs"
    ItemStyle-CssClass="tab"
    SelectedItemStyle-CssClass="selectedTab"
    Runat="server">
    <ItemTemplate>
    <asp:LinkButton
        id="lnkTab"
        Text="<%# Container.DataItem %>"
        CommandName="Select"
        Runat="server" />
    </ItemTemplate>
</asp:DataList>
File: Default.aspx
<%@ Page Language="C#" %>
<%@ Register TagPrefix="user" TagName="TabStrip" Src="~/Control.ascx" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN"
"http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">
<script runat="server">
    protected void TabStrip1_TabClick(object sender, EventArgs e)
    {
        MultiView1.ActiveViewIndex = TabStrip1.SelectedIndex;
    }
</script>
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
    <style type="text/css">
        .tabs a
        {
            color:blue;
            text-decoration:none;
            font:14px Arial,Sans-Serif;
        }
        .tab
        {
            background-color:#eeeeee;
            padding:5px;
            border:Solid 1px black;
            border-bottom:none;
        }
        .selectedTab
        {
            background-color:white;
            padding:5px;
            border:Solid 1px black;
            border-bottom:none;
        }
        .views
        {
            background-color:white;
            width:400px;
            border:Solid 1px black;
            padding:10px;
        }
    </style>
    <title>Show TabStrip</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>
    <user:TabStrip
        ID="TabStrip1"
        OnTabClick="TabStrip1_TabClick"
        Runat="Server" />
    <div class="views">
    <asp:MultiView
        id="MultiView1"
        ActiveViewIndex="0"
        Runat="server">
        <asp:View ID="Products" runat="server">
            <h1>Products</h1>
            We sell a variety of useful products...
        </asp:View>
        <asp:View ID="Services" runat="server">
            <h1>Services</h1>
            We offer a number of services...
        </asp:View>
        <asp:View ID="About" runat="server">
            <h1>About</h1>
            We were the first company to offer products and services...
        </asp:View>
    </asp:MultiView>
    </div>
    </div>
    </form>
</body>
</html>


Use action (Event) in custom control

<%@ Page Language="VB" %>
<%@ Register TagPrefix="ACME" Namespace="MyCustomControls" Assembly="CustomControls"%>
<script runat="server">
   sub Submit(Sender as Object, e as EventArgs)
      "do nothing
   end sub
   
   sub ChangeIt(Sender as Object, e as EventArgs)
      Response.write("Event handled!")
   end sub
</script>
<html><body>
   <form runat=server>
      The custom control produces the following output:
      <ACME:CustomControl id="MyControl" runat="server"
         Message="Hello world!" 
         OnTextChanged="ChangeIt" />
      <asp:Button runat="server"
         Text="Submit"
         OnClick="Submit" />
   </form>
</body></html>

File: CustomControl.cs
using System;
using System.Web;
using System.Web.UI;
using System.Collections.Specialized;
namespace MyCustomControls {
   public class CustomControl : Control, IPostBackDataHandler {
      public event EventHandler TextChanged;
      protected virtual void OnTextChanged(EventArgs e) {
         TextChanged(this, e);
      }
      
      public bool LoadPostData(String PostDataKey, NameValueCollection Values) {
         string strOldValue = this.Message;
         string strNewValue = Values[PostDataKey];
         if (strOldValue != strNewValue) {
            this.Message = strNewValue;
            return true;
         }
         return false;
      }
      
      public void RaisePostDataChangedEvent() {
         OnTextChanged(EventArgs.Empty);
      }
      
      public string Message {
         get {
            return ViewState["Message"].ToString();
         }
         set {
            ViewState["Message"] = value;
         }
      }
      
      protected override void Render(HtmlTextWriter Output) {
         Output.Write("<input name=" + this.UniqueID + " type=text value=\"" + this.Message + "\">");
      }
   }
}
File: CustomControl.vb
Imports System
Imports System.Web
Imports System.Web.UI
Imports System.Collections.Specialized
Namespace MyCustomControls
   Public Class CustomControl : Inherits Control : Implements IPostBackDataHandler
      public Event TextChanged(obj as object, e as eventargs)
      protected sub OnTextChanged(e as EventArgs)
         RaiseEvent TextChanged(Me, e)
      end sub
      
      Public Function LoadPostData(PostDataKey As String, Values As NameValueCollection) As Boolean Implements IPostBackDataHandler.LoadPostData
         dim strOldValue as String = Me.Message
         dim strNewValue as String = Values(postDataKey)
         if not strOldValue = strNewValue
            Me.Message = strNewValue
            return true
         end if
         return false
      End Function
      
      Public Sub RaisePostDataChangedEvent() Implements IPostBackDataHandler.RaisePostDataChangedEvent
         OnTextChanged(EventArgs.Empty)
      end sub
      
      public property Message as string
         Get
            Message = ViewState("Message").ToString
         End Get
         Set
            ViewState("Message") = value
         End Set
      end property
      
      Protected Overrides Sub Render(Output as HtmlTextWriter)
         Output.Write("<input name=" & Me.UniqueID & " type=text value=""" & Me.Message & """>")
      End Sub
   End Class
End Namespace
Источник — «http://nfex.ru/index.php?title=ASP.NET_Tutorial/Custom_Controls/Action&oldid=3292»