.NET news » Search results

How to use Google Calendar in an ASP.NET website

Screen scraping is the process of programmatically accessing and processing information from an external website. For example, a price comparison website might screen scrape a variety of online retailers to build a database of products and what various retailers are selling them for. Typically, screen scraping is performed by mimicking the behavior of a browser - namely, by making an HTTP request from code and then parsing and analyzing the returned HTML.

The .NET Framework offers a variety of classes for accessing data from a remote website, namely the WebClient class and the HttpWebRequest class. These classes are useful for making an HTTP request to a remote website and pulling down the markup from a particular URL, but they offer no assistance in parsing the returned HTML. Instead, developers commonly rely on string parsing methods like String.IndexOf, String.Substring, and the like, or through the use of regular expressions.

Another option for parsing HTML documents is to use the Html Agility Pack, a free, open-source library designed to simplify reading from and writing to HTML documents. The Html Agility Pack constructs a Document Object Model (DOM) view of the HTML document being parsed. With a few lines of code, developers can walk through the DOM, moving from a node to its children, or vice versa. Also, the Html Agility Pack can return specific nodes in the DOM through the use of XPath expressions. (The Html Agility Pack also includes a class for downloading an HTML document from a remote website; this means you can both download and parse an external web page using the Html Agility Pack.)

This article shows how to get started using the Html Agility Pack and includes a number of real-world examples that illustrate this library's utility. A complete, working demo is available for download at the end of this article.

A tool to automatically download files from website that provide Direct Download

Add Facebook Website Tools integration to your ASP based authentication

There are a lot of ways to improve performance in web applications. One of the simplest but most effective methods is to cache images on the client. In this article I would like to show how we implemented image caching for our DotNetNuke website.

In Data Mining, Apriori is a classic algorithm for learning association rules. Apriori is designed to operate on databases containing transactions (for example, collections of items bought by customers, or details of a website frequentation). Here is the implementation of the Apriori Algorithm in C#.

Using Fluent Validation on the website to validate business rules in a Silverlight application

A collection of ExtractionRules, ValidationRules, and Request Plugin that makes ASP.NET and AJAX website testing painless. No need to record tests, write parameterized tests using server-side control names, handle UpdatePanels, simulate clicks on buttons - all from Web Test. Facilitates painless sop

The .NET Framework provides a variety of classes in the System.IO namespace that simplify working with the file system. Using these classes it's possible to delete files and folders, to create new files, to edit existing files, and more. These classes, combined with ASP.NET's suite of Web controls and databinding syntax, make it quite easy to present information about the files on the web server's file system to visitors to your website. With a bit of markup and code, it's possible to add a simple file browser to a web page that allows users to view the files and folders from a particular directory on the web server. Such file browsers are useful if you let users upload content to the website and need to let them view their uploaded content. If you have a folder that contains user-accessible content like images, PDF files and Word documents, a file browser offers a quick and easy way for users to see what content is available and to view content of interest.

Back in 2003 I wrote an article titled Displaying the Files in a Directory using a DataGrid that showed how to list the files of a particular folder in a DataGrid Web control. This dated article still attracts a decent amount of traffic and questions from readers, so much so that I thought it worthwhile to update the content to use the latest technology, namely ASP.NET 4 and the GridView Web control. I also added some new features. For example, the file browser now lists both files and folders, allowing users to view the files in subfolders. Also, I moved the markup and code into a User Control, which simplifies adding the file browser to an ASP.NET page. This article walks through this new, updated version; the complete, working code is available for download at the end of this article.

Validation is one of the most important part of any website. Nowadays, mostly new era websites are having very rich UI, and very much user friedly.User-friendly includes every thing, very good look n feel, excellent user friendly and well placed messages according to the different scenarios.

So here, I am going to discuss all the validators provided by the ASP.NET and for rich UI I'll also discuss in detail the calloutextendor that is part of latest AJAX Tool Kit.