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Let’s create a simple Web page to demonstrate the RegisterArrayDeclaration method. This page provides a slide show where the client-side JavaScript changes the image. In this example, we will search a specified folder on the server and load the names of all the images in a JavaScript array. We will also provide two buttons, one for showing the next image from the list and another for showing the previous one
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="ArrayDeclaration.aspx.cs"
Inherits="ArrayDeclaration" %>
<!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 runat="server">
<title>Untitled Page</title>
<script type="text/javascript">
var curPic = 0;
function processPrevious()
{
if (curPic==0)
{
curPic=Pictures.length - 1;
}
else
{
curPic--;
}
document.getElementById('<%=myPicture.ClientID%>').src=Pictures[curPic];
}
function processNext()
{
if (curPic==Pictures.length -1)
{
curPic=0;
}
else
{
curPic++;
}
document.getElementById('<%=myPicture.ClientID%>').src=Pictures[curPic];
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<table border="1">
<tr>
<td>
<asp:Image ID="myPicture" runat="Server" Height="500px" Width="600px" />
</td>
</tr>
<tr>
<td>
<asp:Button ID="BackButton" runat="Server" Text="Back" />
<asp:Button ID="NextButton" runat="Server" Text="Previous" />
</td>
</tr>
</table>
</div>
</form>
</body>
</html>
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Text;
using System.IO;
public partial class ArrayDeclaration : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
StringBuilder imageArray = new StringBuilder();
// The GetImageArray method searches the Images
// folder and returns a JavaScript array declaration
// for all files contained in the folder.
imageArray = GetImageArray("Image");
// Once we have the array declaration, we simply add it
// to the page by using the RegisterArrayDeclaration method.
// The name of the JavaScript array will be Pictures,
// as specified in the first parameter.
ClientScript.RegisterArrayDeclaration("Pictures", imageArray.ToString());
// Wiring the Back button's click event to
// the processPrevious function. Make sure to
// return false in order to disable post-back operation.
BackButton.Attributes.Add("onClick", "processPrevious();return false;");
//Wiring the Next button's click event to
// the processNext function. Make sure to
// return false in order to disable post-back operation.
NextButton.Attributes.Add("onClick", "processNext();return false;");
}
}
// This function receives a folder name and returns a
// JavaScript array declaration containing names of all files
// from the folder.
protected StringBuilder GetImageArray(string folderName)
{
string Path;
DirectoryInfo Folder;
FileInfo[] Images;
StringBuilder ImageArray = new StringBuilder();
Path = Request.PhysicalApplicationPath + folderName;
Folder = new DirectoryInfo(Path);
Images = Folder.GetFiles();
// Looping through all files in the folder and generating
// a JavaScript array declaration.
foreach (FileInfo Image in Images)
{
ImageArray.AppendFormat("'{0}/{1}',", folderName, Image.Name);
}
// Removing the unwanted last comma.
ImageArray.Remove(ImageArray.Length - 1, 1);
return ImageArray;
}
}