| Page Item | Value |
| Title | Random Image Selector |
| Description | Simple VBScript example for ASP showing how random content can be selected and displayed |
| Keywords | asp, vbscript, random, example, sample |
| Robots Meta Tag | |
| Page Content | ASP Kitchen Search: Go Home | ASP Articles | ASP.NET Articles | Tools | Table Of Contents | What's New ASP Kitchen : ASPWatch.com articles : Random Image Selector Random Image Selector Introduction Here is a small function that allows random images to be displayed on an ASP document. Although this is an easy task to achieve in ASP, or even using client-side JavaScript, the VBScript function shown here has the advantage of not needing to know the number of images within the folder it will take account of images being to added or removed from the images folder. An example random image is shown below. Refresh this page to see another: The RandomImage function is shown below: % Function RandomImage(ImagesFolderPath, ImageFileTypes, ImageDescription) 'Declare variables Dim CompleteImagesFolderPath Dim FileSystemObject Dim ImageFolder Dim Files Dim i Dim ImageFiles Dim File Dim FileName Dim FileExtension Dim RandomNumber 'Find the complete path to image folder by using Server.MapPath CompleteImagesFolderPath = Server.MapPath(ImagesFolderPath) 'Create an instance of the FileSystemObject which allows ASP to 'access the file system Set FileSystemObject = Server.CreateObject( Scripting.FileSystemObject ) 'Check that the folder containing the images exists If Not FileSystemObject.FolderExists(CompleteImagesFolderPath) Then RandomImage = Error 0: Cannot find requested folder Set FileSystemObject = nothing Exit Function End If 'Get the folder containing the images Set ImageFolder = FileSystemObject.GetFolder(CompleteImagesFolderPath) 'Get a list of all the files within the images folder Set Files = ImageFolder.Files 'Use a dictionary object to temporarily store the image file names i = 1 Set ImageFiles = Server.CreateObject( Scripting.Dictionary ) 'Loop through the list of files within the images folder. 'If the file has a file extension that is in the list of 'file types specified in the ImageFileTypes function parameter, 'then add the file name to the ImageFiles dictionary object For Each File in Files FileName = File.Name FileExtension = Right(FileName, Len(FileName) - (InStrRev(FileName, . ))) If InStr(1,ImageFileTypes,FileExtension,vbTextCompare) 0 then ImageFiles.Add i, FileName i = i + 1 End If Next 'Destroy objects that are no longer required Set ImageFolder = nothing Set Files = nothing Set FileSystemObject = nothing 'Initialise the random number generator Randomize ' Check that image file(s) have been found If ImageFiles.Count = 0 Then RandomImage = Error 1: Requested folder does not contain any image files Exit Function End If 'Generate a random number between 1 and the number of image files RandomNumber = Int((ImageFiles.Count) * Rnd + 1) 'Return a hyperlink to a random image file RandomImage = img src= Chr(34) ImagesFolderPath ImageFiles.Item(RandomNumber) Chr(34) alt= Chr(34) ImageDescription Chr(34) Set ImageFiles = nothing End Function % The function uses the FileSystemObject object to access the file system. It checks that the specified image folder exists, and then extracts a list of files within the folder. A link to one of the images (chosen at random) is then returned. There is a certain amount of error checking within the script; it will return an error message if it cannot find the images folder, and also if it cannot find any appropriate image files. The function can be called using the following VBScript: %Response.Write RandomImage( images/ , gif jpeg , My Image )% The function has three arguments. The first (ImagesFolderPath) is the name of the folder containing the images, and it should be a sub-folder of the folder that contains the ASP document. The second argument should be a string containing a list of file types to use as images (e.g. jpeg, jpg, gif). Finally, the last argument is a short sentence to describe your image (which is used as the image s ALT tag). Further reading Sams Teach Yourself Web Development With ASP in 24 Hours . Start learning ASP with this introductory guide. A JavaScript Banner Ad Rotator . Displays a different image after a specific amount of time. Each image is linked to a different URL. Useful Development Tools ASP Documentation Tool Automatically creates developer documentation for ASP 2.0 and 3.0 web applications written in VBScript and JScript. Documentation for Microsoft Access, SQL Server 7/2000 databases and Visual Basic 6.0 components associated with the web application can also be incorporated into the reports. Documentation is created in HTML, HTML Help and plain text formats. View Sample Output (HTML Help format). View Sample Output (HTML Format). Download Trial Version (5.2Mb ZIP file). Index Server Companion The Index Server Companion is a Windows application that extends the functionality of Microsoft Index Server so that it is able to index content from remote websites and also from ODBC databases. As such it can be used as a low cost alternative to Site Server 3.0 Search. View Product Documentation (119K ZIP file). Try Sample Search Facility . Download Trial Version (1.7Mb ZIP file). ASP.NET Documentation Tool Automatically creates developer documentation for ASP.NET web applications written in C# or VB.NET. Documentation for SQL Server 7/2000 databases and C#/VB.NET components associated with the web application can also be incorporated into the reports. Documentation is created in HTML, HTML Help and plain text formats. View Sample Output (HTML Help format). View Sample Output (HTML Format). Download Trial Version (727K ZIP file). SQL Documentation Tool The SQL Documentation Tool creates technical documentation for Microsoft SQL Server 7.0 and 2000 databases. Technical documentation is created in HTML and HTML Help formats. The HTML Help format documentation is fully searchable and cross referenced. The SQL Documentation Tool documents SQL Server Tables, Views, Stored Procedures, Triggers and Table Relationships. View Sample Output (HTML Help format). View Sample Output (HTML Format). Download Trial Version (10.3Mb ZIP file). The Website Utility The Website Utility examines websites for errors and areas that need to be optimised for search engines by using a built in web crawling engine. Errors checked for include broken or moved hyperlinks, missing page titles and missing meta tags. It also generates HTML for use in creating website site maps (table of contents pages - like this one ), and is able to create both client-side JavaScript Search Engines and server-side ASP Search Engines for a website. View Sample Output (HTML Format). Download Trial Version (3Mb ZIP file). Text Workbench Text Workbench is a file search and replacement utility for text files and Microsoft Office documents. Make rapid file replacements on multiple files and folders full of files. Advanced replacement options include regular expressions support. It even works on remote file systems via FTP. A Regular Expression Laboratory allows advanced pattern matching and replacement expressions to be built and tested. This great utility will make your everyday development tasks much easier! Download Trial Version (3Mb ZIP file; you have the option to either install directly from this link or save the file for later installation). Author details Brett Burridge spent two years working in the University of Essex Computing Service, before moving to The Internet Applications Group in the Autumn of 1999, where he developed e-Business applications for a range of corporate clients and dot-com start ups. Brett is presently employed as an Internet developer and technical writer through his own company, Winnersh Triangle Web Solutions Limited . The company produces a number of innovative products, including the popular ASP Documentation Tool , the Index Server Companion , the ASP.NET Documentation Tool , the SQL Server Documentation Tool and The Website Utility . The company is also available for web application design and development at reasonable rates, primarily using Microsoft technologies (ASP, ASP.NET, Visual Basic, SQL Server) but also using open source technologies such as PHP, MySQL and Perl. Specialist services include development of search solutions using Microsoft's Index Server and Site Server 3.0 Search. As well as the ASPAlliance, Brett has written articles for Ariadne.ac.uk and ASPToday , and has contributed recipes to the ASP.NET Developer's Cookbook . links Outside web development, Brett is interested in digital photography (here's my photo gallery ), tropical fishkeeping and collecting contemporary works of art by artists such as Doug Hyde . Article history Random image selector originally published on ASPWatch.com on June 8 2000. Republished on ASPAlliance.com on 26 September 2001. ASP Kitchen : ASPWatch.com articles : Random Image Selector
page content copyright Brett Burridge 1998 - 2004. |
| Image Alt Tags | ASPAlliance A randomly selected image View Sample Output (HTML Help format) View Sample Output (HTML Format) Download Trial Version View Product Documentation Try Sample Search Facility Download Trial Version View Sample Output (HTML Help format) View Sample Output (HTML Format) Download Trial Version View Sample Output (HTML Help format) View Sample Output (HTML Format) Download Trial Version View Sample Output (HTML Format) Download Trial Version Download Trial Version of Text Workbench Download a free ASP Documentation Tool now!!! Download a Free ASP Documentation Tool Now! Search Engine Builder - Build a search engine for your website! |
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