I would now like
to expand a little on what I stumbled through in part I of my Visual Studio 2010 post and touch on a few other features of VS 2010. Specifically, I want
to generate some code based off of an Entity Framework model and tie it up
to an actual data source. Im not going
to take the easy way and tie
to a SQL Server data source, though, I will tie it
to an XML data file instead. Why? Well, why not? This is purely for learning, there are probably much better ways
to get strongly-typed classes around XML but it will force us
to go down a path less travelled and maybe learn a few things along the way. Once we get this XML data and the means
to interact with it, I will revisit data binding
to this data in a WPF form and see if I cant get reading, adding, deleting, and updating working smoothly with minimal code.
To begin, I will use what was learned in the first part of this blog topic and draw out a data model for the MFL (My Football League) - I dont want the NFL
to come down and sue me for using their name in this totally football-related article. The data model looks as follows, with Teams having Players, and Players having a position and statistics for each season they played: Note that when making the associations between these entities, I was given the option
to create the foreign key but I only chose
to select this option for the association between Player and Position. The reason for this is that I am picturing the XML that will contain this data
to look somewhat like this: <MFL> <Position/> <Position/> <Position/> <Team> <Player> <Statistic/> </Player> </Team> </MFL> Statistic will be under its associated Player node, and Player will be under its associated Team node no need
to have an Id
to reference it if we know it will always fall under its parent. Position, however, is more of a lookup value that will not have any hierarchical relationship
to the player. In fact, the Position data itself may be in a completely different xml file (something Id like
to play around with), so in any case, a player will need
to reference the position by its Id. So now that we have a simple data model laid out, I would like
to generate two things based on it: A class for each entity with properties corresponding
to each entity property An IO class with methods
to get data for each entity, either all instances, by Id or by parent. Now my experience with code generation in the past has consisted of writing up little apps that use the code dom directly
to regenerate code on demand (or using tools like CodeSmith). Surely, there has got
to be a more fun way
to do this given that we are using the Entity Framework which already has built-in code generation for SQL Server support. Lets start with that built-in stuff
to give us a base
to work off of.
Right click anywhere in the canvas of our model and select Add Code Generation Item: So just adding that code item seemed
to do quite a bit towards what I was intending: It apparently generated a class for each entity, but also a whole ton more. I mean a TON more. Way too much complicated code was generated now that code is likely
to be a black box anyway so it shouldnt matter, but we need
to understand how
to make this work the way we want it
to work, so lets get ready
to do some stumbling through that text template (tt) file. When I open the .tt file that was generated,
right off the bat I realize there is going
to be trouble there is no color coding, no intellisense no nothing! That is going
to make stumbling through more like groping blindly in the dark while handcuffed and hopping on one foot, which was one of the alternate titles I was considering for this blog. Thankfully, the community comes
to my rescue and I wont have
to cast my mind back
to the glory days of coding in VI (look it up, kids). Using the Extension Manager (Available under the Tools menu), I did a quick search for tt editor in the Online Gallery and quickly found the Tangible T4 Editor: Downloading and installing this was a breeze, and after doing so I got some color coding and intellisense while editing the tt files. If you will be doing any customizing of tt files, I highly recommend installing this extension. Next, well see if that is enough help for us
to tweak that tt file
to do the kind of code generation that we wantDid you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.
