Downtown Metro Toronto .NET UG Inaugural Meeting!

Finally a downtown user group.  First week of every month - and the first one is April 1st - no fooling..at 200 Bloor St. East (Manulife) at Jarvis. This is also the first date on the MSDN Canada .NET User Group Tour across Canada. There is also a raffle for an XBox.

The sad news is that this meeting is going to get cut off at the first 200 people - so register soon by sending an email to GrahamMarko@rogers.com.

http://www.metrotorontoug.com/

speaker: Adam Gallant
location: Manulife Financial Building 1st Floor 200 Bloor Street East Toronto

Better Web Development

In this session, we will focus on some fundamentals in web development, including a special drill-down on security and caching. We will cover an overview of the .NET security, and specifically important aspects in ASP.NET security and best practices. We will also cover, at a high-level, the caching mechanisms used by ASP.NET.

Upstaged by Ballmer

So it would seem I'm upstaged by Steve Ballmer who is coming to town the same day as the CTTDNUG presentation I was making about Whidbey.  So in the interest of the greater good - my talk has been postponed until Mar 31.

The “Ballmer Developer Briefing” is mostly about Security...if that interests you?

What do you mean “IF” - of course that should matter to you. It should matter to everybody. Writing secure code isn't just about logging in you know. It's about keeping your code safe and more importantly your end users machines and data safe and not allowing your software to act as a gaping hole into their system or data be it through spoofing or SQL Injection Attacks. Writing code these days is more of a liability than it ever has and we all have to be responsible - so do yourself and the rest of the world a favour and brush up on your knowledge of security. Either that, or hire a good lawyer.

I'm so convinced this is a an important event (and sorry that I had to cancel my presentation) that ObjectSharp is co-sponsoring a bus for members of the CTTDNUG that will travel to Toronto from Kitchener and back. And for those of you no where near Kitchener? Did I mention that parking is free?

See you there.

Datasets vs. Custom Entities

So you want to build your own entity objects? Maybe you are even purchasing or authoring a code-gen tool to do it for you. I like to use Datasets when possible and people ask why I like them so much. To be fair, I'll write a list of reasons to not use datasets and create your own entities - but for now, this post is all about the pros of datasets. I've been on a two week sales pitch for DataSets with a client so let me summarize.

  • They are very bindable.
    This is less of an issue for Web forms which don't support 2 way databinding. But for Win forms, datasets are a no brainer. Before you go and say that custom classes are just as bindable and could be, go try an example of implementing IListSource, IList, IBindingList and IEditableObject. Yes you can make your own custom class just as bindable if you want to work at it.
  • Easy persistence.
    This is a huge one. Firstly, the DataAdapter is almost as important as the DataSet itself. You have full control over the Select, Insert, Update and Delete sql and can use procs if you like. There are flavours for each database. There is a mappings collection that can isolate you from changes in names in your database. But that's not all that is required for persistence. What about optimistic concurrency? The DataSet takes care of remembering the original values of columns so you can use that information in your where clause to look for the record in the same state as when you retrieved it. But wait, there's more. Keeping track of the Row State so you know whether you have to issue deletes, inserts, or updates against that data. These are all things that you'd likely have to do in your own custom class.
  • They are sortable.
    The DataView makes sorting DataTables very easy.
  • They are filterable.
    DataView to the rescue here as well. In addition to filtering on column value conditions - you can also filter on row states.
  • Strongly Typed Datasets defined by XSD's.
    Your own custom classes would probably be strongly typed too...but would they be code generated out of an XSD file? I've seen some strongly typed collection generators that use an XML file but that's not really the right type of document to define schema with.
  • Excellent XML integration.
    DataSets provide built in XML Serialization with the ReadXml and WriteXml methods. Not surprising, the XML conforms to the schema defined by the XSD file (if we are talking about a strongly typed dataset). You can also stipulate whether columns should be attributes or elements and whether related tables should be nested or not. This all becomes really nice when you start integrating with 3rd party (or 1st party) tools such as BizTalk or InfoPath. And finally, you can of course return a DataSet from a Web Service and the data is serialized with XML automatically.
  • Computed Columns
    You can add your own columns to a DataTable that are computed based on other values. This can even be a lookup on another DataTable or an aggregate of a child table.
  • Relations
    Speaking of child tables, yes, you can have complex DataSets with multiple tables in a master detail hierarchy. This is pretty helpful in a number of ways. Both programmatically and visually through binding, you can navigate the relationship from a single record in master table to a collection of child rows related to that parent. You can also enforce the the referential integrity between the two without having to run to the database. You can also insert rows into the child based on the context of the parent record so that the primary key is migrated down into the foreign key columns of the child automatically.
  • Data Validation
    DataSets help with this although it's not typically thought of as an important feature. It is though. Simple validations can be done by the DataSet itself. Some simple checks include: Data Type, Not Null, Max Length, Referential Integrity, Uniqueness. The DataSet also provides an event model for column changing and row changing (adding & deleting) so you can trap these events and prevent data from getting into the DataSet programmatically. Finally with the SetRowError and SetColumnError you can mark elements in the DataSet with an error condition that is can be queried or shown through binding with the ErrorProvider. You can do this to your own custom entities with implementation of the IDataErrorInfo interface.
  • AutoIncrementing values
    Useful for columns mapped to identity columns or otherwise sequential values.

This is not an exhaustive list but I'm already exhausted. In a future post, I'll make a case for custom entities and not DataSets, but I can tell you right now that it will be a smaller list.

Visual Studio .NET Tips and Tricks @ PDC

I'm hosting a birds of a feather Sunday night from 8-9pm at the Microsoft PDC. The topic is Visual Studio .NET Tips and Tricks. Hope to see you there - and grab a beer or three afterwards.

Code:
BoF29
Room: Room 402AB