Image Rotator : CompositeControl « Custom Controls « ASP.NET Tutorial






  1. ASP.NET Tutorial
  2. Custom Controls
  3. CompositeControl
File: ImageRotator.cs

using System;
using System.Collections;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.ComponentModel;

namespace myControls
{
    [ParseChildren(true, "ImageItems")]
    public class ImageRotator : WebControl
    {
        private ArrayList _imageItems = new ArrayList();

        public ArrayList ImageItems
        {
            get
            {
                return _imageItems;
            }
        }

        protected override void RenderContents(HtmlTextWriter writer)
        {
            if (_imageItems.Count > 0)
            {
                Random rnd = new Random();
                ImageItem img = (ImageItem)_imageItems[rnd.Next (_imageItems.Count)];
                writer.AddAttribute(HtmlTextWriterAttribute.Src, img.ImageUrl);
                writer.AddAttribute(HtmlTextWriterAttribute.Alt, img.AlternateText);
                writer.RenderBeginTag(HtmlTextWriterTag.Img);
                writer.RenderEndTag();
            }
        }
    }

    public class ImageItem
    {
        private string _imageUrl;
        private string _alternateText;

        public string ImageUrl
        {
            get { return _imageUrl; }
            set { _imageUrl = value; }
        }

        public string AlternateText
        {
            get { return _alternateText; }
            set { _alternateText = value; }
        }
    }
}

            


File: ShowImageRotator.aspx

<%@ Page Language="C#" Trace="true" %>
<%@ Register TagPrefix="custom" Namespace="myControls" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head id="Head1" runat="server">
    <title>Show ImageRotator</title>
</head>
<body>
    <form id="form1" runat="server">
    <div>

    <custom:ImageRotator
        id="ImageRotator1"
        Runat="server">
        <custom:ImageItem ImageUrl="Image1.gif" AlternateText="Image 1" />
        <custom:ImageItem ImageUrl="Image2.gif" AlternateText="Image 2" />
        <custom:ImageItem ImageUrl="Image3.gif" AlternateText="Image 3" />
    </custom:ImageRotator>

    </div>
    </form>
</body>
</html>








14.20.CompositeControl
14.20.1.Building Composite Controls
14.20.2.Building Hybrid Controls
14.20.3.Performing layout with an HTML table.
14.20.4.Item Rotator
14.20.5.Image Rotator
14.20.6.Creating a Default Template
14.20.7.File: Product.cs
14.20.8.Supporting Two-Way Databinding
14.20.9.Creating Templated Databound Controls