The "life management" of DataContext has motivated many design patterns with respect to LinqToSql. DataContext is central to LinqToSql and it's life needs to be controlled correctly so you can submit changes to your entities to the Datasource. This is a big change from how data access patterns are being done traditionally where you don't need to hold on to the instance of your Data Access Layer, instead you move around your entity instances.

 

Author Keith Craig in this blog creates a pattern where the DataContext instance is Request Scoped: the DataContex instance gets tied to the HttpContext object- the blog comes with explanation and complete code examples.

Linq To SQL has been out there released for a few months now and everybody who is desigining a new .Net application is probably considering it as an option for their data access. Linq has been hyped up by Microsoft for a long time now ; it has aroused people's curiosity very much- with Linq To Sql in the market , everybody is trying to see if they can adapt it in their architecture for better , faster results.

 

In this 2 series blog by Hilton Giesenow he discusses at length the Performance as well as Security considerations on using Linq as a design choice for your Business Layer as well as Data Access Layer. He  also discusses how Linq To Sql's dynamic query can be intelligently mixed with stored procedures to get better results. He gives several code example to prove his ideas along with code snippets of what Linq To Sql generates.

 

Read both the blogs if you are seriously considering Linq To Sql as an option -

This interesting blog uses LINQ with FlickrNet objects which wrap up the Flickr API and gets back a photo collection based on tag , date and title. The blog gives a sample that gives a first hand practical use of LINQ and it's simplicity. The blog is titled as Bashmohandes. The blog gives a clear C# example of implementation of IQueryable interface.

 

FlickrNet is a project  on CodePlex .

One of the few questions that one would ask while upgrading from the older versions of .Net framework to the new 3.0 or 3.5 are what do these include ? Why should we or should not we upgrade?

 

The author in this blog summarizes the assemblies that come as part of the 3.0 as well as the 3.5 versions.  The fact that 3.0 and 3.5 both include the 2.0 assemblies explains the multi targetting support that comes with these new versions . It is important to understand what kind of runtime both 3.0 and 3.5 are - before we consider upgrading our applications to any one of these versions. It is undoubtedly a big bonus to be able to target the 2.0 version also with new 3.0 or 3.5 runtime. That's exactly what this blog explains , the composition of the new 3.0 and 3.5 runtime.

 

This article at CodeIdol goes in detail how to use the CreateUserWizard and the Membership API to implement registration of a user and sending either a HTML or Text email notification using MailDefinition template. The article is quite thorough in going through all the steps with code examples.

 

It goes through all the properties of the CreateUserWzard controls to set up their look and feel. It also discusses the Email feature in detail. One very interesting aspect of the article is it gives tips in between in a box which are useful. For Example:

 

"

Did you Know?

To add a text file or HTML page to your website, right-click on the project name in the Solution Explorer and choose the Add New Item menu option. In the Add New Item dialog box, you'll find Text file and HTML page file types.

 

"

In this article author Craig Shaw uses the Membership API, CreateWizard control and the MaiDefinition template to control the process of User activation after registration. The Membership API and controls offer a lot of basic functionality that can be reused and tailored very quickly to put together a reasonable and professional quality authentication and authorization mechanism.

 

The author gives clear code examples in C# to go from the beginning to end where a user is created and inactivated in the beginning. An email is triggered which sends a URL to activate the User. Then the User is activated after he clicks on the URL. All code examples for events and web configuration are listed clearly. The OnSendingMail event raised by CreateUserWizard is also discussed in detail.

 

This blog named as Thoughts.Generate() uses the MailDefinition template in ASP.Net 2.0 to send emails using other controls other than the CreateUserWizard control. The MailDefinition templates are typically used in Membership API where mails are sent after a user is registered or an email needs to be sent for password recovery in forgot password implementation. This feature of Membership did not get as much attention because it is mostly used in relation with the Membership related controls.

 

However in this blog the author takes this feature and creates a generic model associated with any other control that can trigger and send emails based on the configuration with this template.

 

Although this blog is a little old, however it discusses a very good feature of the framework that can be very well used even now; The MailDefinition tag looks like this:

 

 <MailDefinition
BodyFileName="~/Registrered.txt"
From="http://www.dotnettopics.com"
Subject="Thanks for registering with DotNetTopics">
</MailDefinition>

Code Smith has made a name for itself in the .Net community ; however there is also that portion of the developer community which still does not understand the importance of tools like this , how it can improve coding speed and efficiency. Most projects have the simple need for Objects that need to map against the relational database schema. This task can become very mechanical , mundane and arduous if you had a larger database. A tool like Code Smith can simplify this with a few clicks you can generate a custom object against a database table that generates properties that map to columns.

 

Code Smith also comes with the feature of templates that allows you to create VB Script templates that can customize the code generation. If you have VB / VB script background, it's a no brainer.  Otherwise the learning curve is very small.

 

It is also priced very reasonable: Standard Edition at : $99 and Professional Edition at $399. Within a few hours of using CodeSmith you can, recover the cost of buying the product.

 

The only downside is if you need to make modifications and additions to the generated code, you would have to do it yourself. However it definitely saves the time required to generate the initial repetitive code which can be a major cost saving in itself.

There are thousands of great blogs being written on the web, there is so much to learn from them. This blog is another one of those , the author titles the blog as Hacky Hacky . Here the author takes the example of HtmlAgilityPack, an open source CodePlex project for URL scraping and uses LINQ To XML syntax to scrape the URL, convert it to XML document and traverse through the document to find all the images on the URL.

 

A very nice blog to understand LINQ To XML syntax, and HtmlAgilityPack.

In this personal website of Jon Skeet he lists out all the new features of C# 3.0 language. The features that he summarises with examples are: