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A Visual Basic Custom Hover Button Control with PostBack & Events
(aspfree.com) An good tutorial and VB source code for creating a custom rollover button control which features postback. This tutorial is particularly useful in showing how to handle the Click/Postback event. This button technique has a few weak points though - it uses a table cell background image and relies on the cursor:hover style which does not work in Firefox. Definitely read it for the event code though.
[ Covers: style cursor:hover postback rollover hover animated button postback event ]
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4 Guys From Rolla
One of the best site for programmers of ASP.NET looking for quality technical articles and source code examples. The guys behind this site are some of the most ASP.NET-savvy people around.
[ Covers: mssql tsql vb.net c# c sharp visual studio ]
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Deluxe Custom Paging in ASP.NET using Visual Basic
(4guysfromrolla.com) Instead of using the DataGrid control, which can involve performance penalties and impose considerable constraints, and instead of struggling through all the complexities of building a custom paging class on your own, check out this article.
[ Covers: dal database dataset datagrid ]
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RollOver Button Custom Server Control in C#
(4guysfromrolla.com) Build a roll-over button server control which causes a postback. All we need to do is create a control that derives from LinkButton, add properties for the default image URL and the roll-over image URL, have the control emit a bit of client-side script, and then (finally), override the RenderContents() method so that our roll-over button generates the HTML for an img tag inside the a tag (as opposed to merely displaying the Text property, which is what the LinkButton does).
[ Covers: animated button hover onmouseover onmouseout C# C Sharp rollover ]
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Injecting Client-Side Script from an ASP.NET Custom Server Control
(msdn) When building some of the more sophisticated Custom Server Controls you might think up you might want to have the control inject some custom Javascript into the resulting page on which it is rendered. An example is if you are building a custom Rollover Button class. This is the correct way to inject such Javascript from a Custom Control.
[ Covers: IsClientScriptBlockRegistered RegisterClientScriptBlock PreRender ]
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VB.NET Encoding and Decoding - Binary To Text
(codeproject.com) How to build a class in VIsual Basic which can use several popular algorythms to encode or decode data between binary and text formats. A Web Application might use this method to make a Query String safe and more secure regardless of the data you wnat to wrap up in it. You might be transporting data via HTTP and want to prepare it. It's a useful and typical need for all kinds of applications. Some good general programming tips.
[ Covers: quoted printable base64 uuencode yenc text binary encode decode algorythm visual basic source code ]
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DES CryptoStream Class Library in VB.NET - Protect Sensitive Data in Transit - XML and HTTP-Safe
This is source code for a nice simple and small crypto class written in VB.NET. Encryption is via DES and then Base 64 encoded for safe text-based handling via HTTP, SOAP, XML etc. This is essential for any Visual Basic ASP.NET Web Application that is going to touch, transfer or store sensitive data. This code can help make your app compliant with HIPAA, Sarbanes-Oxley and other regulations governing the handling of financial or personal information.
[ Covers: DES DESCryptoServiceProvider MemoryStream CryptoStream CreateDecryptor CryptoStreamMode UTF8 Encoding.UTF8.GetBytes CreateEncryptor HIPAA Sarbanes Oxley ]
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Microsoft .NET Framework SDK QuickStart Tutorials
(asp.net) This is fresh and new for 2.0. A great place to start when you are tackling any new aspect of .NET. The best thing about these tutorials and source code samples is that they progress in a gradual, stepwise manner with a little piece of source code and working demo at each increase in complexity. For example, this was one of the best places to go to learn how to build Custom Server Controls - one step at a time. Few other tutorial sites have this stepwise benefit. Many very important topics are covered. Web Services have a whole new section.
[ Covers: ASP.NET C#.NET quick-start tutorials samples demos source code msdn .NET Framework Web Services ADO.NET Validation Master Pages Internationalization Caching Tips Tricks ]
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ASP.NET Custom Web Control Gallery
(asp.net) Microsoft's gallery of 3rd party Custom Web Controls for free download and for sale for reasonable prices. Many types and over 1000 total. Many good ones to choose from. This is the quick way to really spice up your ASP.NET app as well as a great place to get ideas from and see how other developers have done it.
[ Covers: button navigation chart rotator ticker grid calendar validation list mobile menu tree freeware shareware ]
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Write Text to a File and Read Text From a File using System.IO - VB.NET
(freevbcode.com) This is a quick and simple Visual Basic how-to with source code, particularly useful for debugging when you want too have a quick look at the variable inside your app and are too lazy or busy to set up more sophisticated debugging. It's also a good place to start learning file I/O.
[ Covers: file i/o read write text file streamreader readtoend streamwriter System.IO open close visual basic ]
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Object Oriented Programming for VB.NET
(ondotnet.com - O'Reilly) A very good tutorial to introduce the essential concepts and techniques of OOP in VB.NET. The first of 2 parts covers Classes, Class Members, Instantiating an Object, Namespaces, Access Types, Static Members, Constructors, Inheritance, Methods, Non Inheritable Classes and more. Follow the link to Part 2 which covers Method Overloading, Method Overriding, Polymorphism and more. A must-read for VB people.
[ Covers: overloads overrides public protected private friend module class imports NotOverridable MustInherit Overridable derived ]
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VB.NET Data Types - VB7 Data Types and Equivalent .NET Framework Type Structures
(ondotnet.com - O'Reilly) A basic foundation of programming in any language is knowing the data types you can work with and what you can do with them. This article goes further than just introducing them however, and also explains important differences between VB7, VB.NET and earlier versions of Visual Basic and more. This is a thorough and important overview of variables and data types in VB.NET. Another must-read.
[ Covers: boolean byte char date datetime decimal double integer int16 int32 int63 long object short single string valuetype variant stringbuilder System.Object Sbyte UInt16 UInt32 Uint 64 Len Substring ]
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Dealing with Images in Content Management Systems - A Powerful C# Custom Server Control
(thecodeproject.com) This is an advanced and detailed tutorial and source code for a powerful ASP.NET custom server control that allows the end user to upload an image from the local file system, and crop, scale, and optimise it to obtain a satisfactory web image. The server control inherits from the new CompositeControl class, which makes it easier to compose new server controls out of existing, simpler controls. This control makes heavy use of JavaScript, DOM, and CSS.
[ Covers: WebControls.FileUpload ImageWidth ImageHeight IImageProvider GDI+ System.Drawing HttpHandler BuildAsControlLibrary HandlerPath CompositeControl override CreateChildControls ]
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ASP.Net's Built-in Web Security
(orcsweb.com) ASP.NET has some new features that allow a developer to easily secure certain areas of a web site. A brief introduction to the easy Access Control features of ASP.NET. On a side note - check out ORCSweb's high quality ASP.NET web hosting - this is not an ad - I did the research and they are probably the best - but a little more expensive.
[ Covers: authentication authorization session web.config ]
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ASP.NET Common Web Page Class Library (4 part series)
(codeproject.com) Most serious ASP.NET developers end up creating a suite of classes and controls that they use again and again to solve all the typical web site development needs. Things like: a basic page template/class, authentication and authorization, an emailing or data-capturing contact page, a dynamic navigation menu class etc. Well, this 4-part series is about how one developer did that in VB.NET and it includes all the source code of course. You can make use of his classes or just learn a lot from seeing how he did it.
[ Covers: authentication authorization navigation menu page template email contact form web application framework ]
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Meditating Upon the ASP.NET Code-Behind Model
(developer.com) A nice little introduction to what code behind is and what things to consider when deciding to use it. You can build a nice little site without code behind - but soon enough you will really want the benefits of a few things: Code-Behind, Assemblies and Custom Controls. The sooner you take the leap the faster you can build sophisticated sites with the minimum of effort. Quirks of using Visual Studio .NET are also discussed. Personally - I do just fine develping ASP.NET without VS anywhere in sight.
[ Covers: code-behind in-lin code assemblies visual studio .NET ]
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web.config - Specify Configuration Settings for your ASP.NET Site or Application
(4guysfromrolla.com) A handy litte introduction to the basics of web.config. Some trivia not discussed in the article: Apache heads know web.config's older cousin the .htaccess file. Like .htaccess, web.configs can be inside any folder and work in a cascading manner to set fine grained site and application, authentication, authorization and other configuration settings as you need them tailored to any directory or page of your site. When an equivalent setting is encountered, the lower web.config's value overrides the corresponding value of the one above it.
[ Covers: web.config .htaccess ASP.NET configuration settings ]
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Implementing Model-View-Controller in ASP.NET
(msdn) Say you are building a very sophisticated Web application in Microsoft ASP.NET, and, based on the complexity of your application, you need to separate different aspects of the program to reduce code duplication and to limit the propagation of change. For the largest web apps you might be architecting at this level - enter the Model View Controller. I can tell you that this is how we did it at the largest e-commerce site on the Internet (albeit in mod_perl) - and at this scale such architecture perspectives are essential.
[ Covers: model view controller web application architecture class data access layer ]
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ASP.NET DataGrid Column Sorting - Both VB and C#
(dotnetjunkies.com) How to implement column sorting with the DataGrid control. This is one of the reasons to use a DataGrid in the first place - because ASP.NET handles so much of the work for you. Want to be able to just click on the column header name in your DataGrid and sort by that column? If so read this article. Visual Basic and C# source code included.
[ Covers: datagrid order by sort column sorting vb visual basic c# c sharp ]
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ASP.NET DataGrid Paging (Built-In Paging - VB and C#)
(dotnetjunkies.com) This is an introduction to the one of the DataGrid's primary features - it's built in paging. In all honesty - I quickly moved from the built-in paging to custom paging for performance reasons but the built-in method is obviously a very fast way to get paging going. It's suited to smaller databases. If you are just learning or your database is small and your deadlines short - check it out.
[ Covers: datagrid paging asp.net visual basic vb C# C sharp ]
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ASP.NET DataGrid Paging (Custom Paging VB and C#)
(dotnetjunkies.com) For performance and customization reasons most developers will not be satisfied with just using the DataGrid's built-in paging and will want to code their own paging. This is Doug Seven's method which uses Stored Procedures - look on this site for the link to another article by Scott Mitchell which does the same with inline SQL. This is one of those things that can be done in a number of ways. Doug's technique is definitely worth taking a look at.
[ Covers: custom paging stored procedure visual basic vb.net c# c sharp datagrid database performance ]
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Database Record Locking in ASP.NET - Handling Multiple Concurrent Users (VB)
(15seconds.com) Many if not most Web Applications you might build with ASP.NET will likely need to support multiple concurrent users editing and updating data at the same time. It's a classic problem - what do you do when 2 users want to edit the same record at exactly the same time? The simplest and most common method is with database record locking. It's important to think this problem through and handle the problem elegantly. This article is quite substantial and takes you well along the way to a good solution. It's done in Visual Basic.
[ Covers: transactions record locking row lock concurrency multi-user multiple user database ]
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Creating a Data Access Layer in .NET - Advanced, Robust, Relational Web Database Applications (2 Part Article)
(15seconds.com) This is a sophisticated, advanced-level article on how to create a data access layer (DAL) for a Relational Web Database Application using ASP.NET. Featuring transactional integrity, concurrency integrity, error handling and a lot more. Follow this article using it's included source code and develop your own DAL, at that point you will be able to build very robust Web Database Applications. Stored procedures are used. Pessimistic and optimistic application locks are discussed. Part 2 gets into the actual data-access code using Visual Basic.
[ Covers: web application database transaction security performance stored procedures pessimistic application lock concurrency concurrent multi-user ]
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ADO.NET Overview - Connections, DataReader, DataSet, DataAdapter
(gotdotnet.com) This is the basic overview of accessing database and other data sources like XML using ASP.NET. Some topics discussed: Connections, DataReader, DataSet, DataAdapter. This is one of the good places to get started from. The Quick-start tutorials are good because they show you little demos with source code at each step of increasing complexity.
[ Covers: ado.net ado asp.net quickstart how-to connection sqlconnection dataset datareader dataadapter ]
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Facing .NET Technical Interviews
This is a long and detailed list of questions and answers and many brief overviews of the key concepts that are likely to come up during a rigorous technical interview for a senior .NET development position. This is a great article to read for anyone who -thinks- they are ready for that tough technical .NET interview. After reading this you will certainly be humbled a bit and back to the studying for a while. Then you will be in a better position to land that great job you want.
[ Covers: technical job interview preparation asp.net c#.net vb.net c++.net clr managed code senior developer ]
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Basic Use of the Repeater Control - Bind a DataSet to It
(W3 Schools) This is a very basic introduction to the use of the Repeater Control. I recommend getting familliar with the Repeater Control and learning about more advanced use of it as soon as possible as it can be quite powerful. When you want to really cusomize the look and feel of grid output the Repeater Control can be just what you are looking for. The DataGrid has other features for selecting and editing data, but the Repeater Control can produce exactly the HTML you want more easily.
[ Covers: repeater headertemplate itemtemplate footertemplate bind dataset repeater control ]
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Web.config File Demystified
(sitepoint.com) A good and fairly detailed overview of the web.config file. Each major section is discussed. There is a link to the MSDN reference for all web.config tags which can go in the System.Web section.
[ Covers: web.config appsettings authentication authorization customerrors globalization httpruntime sessionstate trace system.web ]
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Web.Config - Referencing External Config Files For Server-Specific Convenience
(devx.com) A typical scenario - you have a development and a production server or even other servers and each one might use a different connection string for it's database, but you develop your apps with a single web.config and you always have a little mess keeping the connection string right since you don't want to think about which server when you update the entire site. Simple answer - reference a separate file with just the connection string in it and leave that file out of your site updates. Cool.
[ Covers: web.config separate external config file site update development production staging ]
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How to Create a GUID - Globally Unique Identifier - Visual Basic
(freevbcode.com) GUIDs are useful for many purposes - perhaps as a unique row identifier for a Database application. You will recognize them as the IDs that are used in the Windows Registry. This bit of source code shows you how to call the OLE32.DLL to create a GUID.
[ Covers: guid globally unique identifier ole32.dll primary key ]
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Sending Email with ASP.NET - Including Attachments
A simple and full-featured technique for sending email with attachments from an ASP.NET web page. Source code included.
[ Covers: asp.net tutorial source code send email attachment ]
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An Extensive Examination of the DataGrid Web Control - 18-Part Tutorial
(4guysfromrolla.com) This is an indepth 18-part tutorial including source code examples which examines nearly every aspect of using and customizing ASP.NET's DataGRid control. Written by an authority on the subject, Scott Mitchell.
[ Covers: asp.net datagrid paging bind headerstyle footerstyle itemstyle alternatingitemstyle ]
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Custom DataGrid Control Derived from DataGrid - Case Study in C# and Visual Basic
(dotnetjunkies.com) This tutorial with source code creates a custom DataGrid control derived from DataGrid with enhancements. The greatest value I see in this article is showing the source code side by side in C# and Visual Basic, thus providing a valuable resource for people who occasionally translate such code between the 2 languages. Additionally, customizing DataGrid is a common and very beneficial thing. The specific enhancements here are to allow the alternating of row colors to occur every 3 or 5 rows instead of every other row.
[ Covers: custom datagrid web control c sharp c# vb visual basic inherits overrides using ]
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Uploading Files with ASP.NET using Visual Basic
(aspheute.com) Uses the System.IO class to handle uploading of files to your application. This tutorial is in Visual Basic.
[ Covers: enctype multipart/form-data file upload asp.net ]
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Detecting ASP.NET Session Timeouts - And How Session Works
(aspalliance.com) This article with source code and a forum discussion starts with a very good description of how Session works on IIS and ASP.NET. Then a custom base page class is created which inherits from System.Web.UI.Page and is designed to replace it. The goal is to automatically detect session timeouts for every page on a website and then redirect to a helpful notice page which tells this to the user. The idea is interesting and in reading the article you will understand the workings of session better.
[ Covers: session sessionid page inherits cookie expires timeout httpsessionstate SessionState.SessionStateModule ]
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Authentication and Authorization in ASP.NET - A High Level Overview
(4guysfromrolla.com) A general overview of the options and how authorization and authentication work in ASP.NET. This article does not get into the syntax and code of how to do it but it does present a picture of how the major components of the system interact with each other. A good place to start to understand more about how Windows and NTFS interact with ASP.NET and IIS in this area.
[ Covers: impersonation ntfs domain permission integrated windows forms passport anonymous basic digest provider ntfs group asp.net ]
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Authorization Configuration Syntax for ASP.NET - web.config
(MSDN) This is the syntax reference for specifying in web.config which pages and directories are either allowed or prohibited access for various users.
[ Covers: allow deny users roles authorization verb location file url FileAuthorizationModule URLAuthorizationModule ]
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Configure Specific Directories Using Location Settings - ASP.NET web.config
(MSDN) About specifying general configurations on a per directory basis.
[ Covers: location web.conifg directory configuration asp.net path system.web ]
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SQL Injection Attacks - Form Input Vulnerability - How to Protect your ASP.NET Web App
(MSDN) This is a quality MSDN how-to article with an excellent examination of the problem of SQL-Injection attacks and good source code for solutions to various parts of the problem. ASP.NET code, stored procedures, parameters and database permisson issues are all discussed. Specific emphasis on MSSQL vulnerabilities. A must-read for web-database application developers.
[ Covers: sql injection vulnerability attack illegal character regex regular expression stored procedure parameter permission malicious form input ]
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Malicious Code Injection Attacks Against ASP.NET - Protect your Web App
(MSDN) Covers different topics than the other excellent MSDN article about SQL-Injection Attacks. This article covers protection against all kinds of malicious code which can easily subvert an unprotected web form. Explores the problem then provides source code for multiple solutions to this serious issue. Discusses HttpRequestValidation, ASP.NETs generalized built-in protection and various specific constraints on user input. Another must-read for all developers.
[ Covers: HttpRequestValidation SQL-Injection cross-site scripting attack RegularExpressionValidator RegularExpressions HTML input query string cookie ]
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DOS Batch File Tutorial - The Basics of .bat
DOS Batch Files are back! As an ASP.NET Developer you use will almost certainly use them to quickly compile and recompile your Assemblies and Custom Controls. I've been finding myself wanting to customize them, but I had to go back and relearn things like why to use :: instead REM to add coments. It's almost like watching the Brat Pack in an 80's movie. DOS is bitchin'! This is a nice little tutorial for beginners.
[ Covers: .bat PATH DOS REM :: PAUSE @ECHO CLS CD ]
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Tracking Visitors with ASP.NET - A Full Analysis of All Methods with Source Code
(15seconds.com) This is a long and very thorough article, tutorial and source code which covers in some detail most of the issues and techniques of tracking visitors to your website. In addition to traditional methods, this offers ASP.NET-specific methods and code. Everything from log file analysis, cookies and sessions to a custom ASP.NET tracking class is covered. Excellent if you are developing an ecommerce or marketing-oriented site. The need for a site Privacy Policy is necessarily discussed.
[ Covers: log file analysis cookie request object ip referrer user agent referrer session visit hit track HTTPContext Global.asax Web.Mail ]
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Protect Forms from Bot Attacks using Captcha Images in ASP.NET and C#
(codeproject.com) Captcha refers to those wavy images of letters and numbers you have to read and type back in which you see on the important pages of most major sites which accept user input into a form and are vulnerable to bot attacks. This is strong protection to ensure that the form is submitted by a human and not a script, commonly protecting forms for services like whois, or web-mail account creation. Recommended for site contact forms these days. This is a tutorial with source code in C#.
[ Covers: captcha script bot robot attack spam sql injection human security image type C# asp.net ]
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Protect Forms from Bot Attacks using Captcha Image Server Control in ASP.NET and Visual Basic
(codeproject.com) Enhancement in Visual Basic. Captcha refers to those wavy images of letters and numbers you have to read and type back in, which you see on the important pages of most major sites which accept user input into a form. This is strong protection to ensure that the form is submitted by a human and not a script, commonly protecting whois, account-creation forms, contact forms and more. This is a full server control enhancement of the original approach adapted to vb.net from c#.
[ Covers: server control captcha script bot robot attack spam sql injection human security image type visual basic vb.net asp.net ]
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Captcha Overview - Fighting SpamBots with .NET and AI
(15seconds.com) Rather than an indepth technical tutorial, this is a good general overview of what Captcha is, why and how many of the major commercial sites use it to fight spam bot and script attacks against their critical user-input pages. Compares different Captcha variations. Links to multiple articles which get into the actual how-to and source code.
[ Covers: captcha overview spam bot script attack protection godaddy yahoo gimpy cmu alta vista msn hotmail network solutions passport authentication ]
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Send Email From an ASP.NET Page - Contact Form Using MailMessage and SmtpServer Objects
The System.Web.Mail namespace of ASP.NET provides rich emailing functionality via SmtpMail, MailMessage and other objects. Much improved over the old days of CDO and CODNTS - this article will get you on your way to adding this standard and valuable functionality to your ASP.NET site.
[ Covers: MailMessage attachments from to cc bcc body bodyformat priority subject headers bodyencoding smtpmail smtpserver send asp.net contact form cdo cdonts ]
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Create a Site Search Engine in ASP.NET
A tutorial with source code in Visual Basic to create a full featured site search which can either search a site on demand or periodically crawl a site and the search from an XML index file the crawler has created. It can also search your site's dynamic pages. It also makes use of your site's meta tags keywords, description etc.
[ Covers: site search search engine crawler crawl xml index regex rank ]
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