Jeff Sheldon

KnockoutJS….Cheating Much?

Jeff Sheldon — Wed, 16 Mar 2011 02:47:14 GMT

Ok so I’ve been following KnockoutJS for a while but I haven’t taken the time to play with it yet. Regardless, I recently noticed the extensibility to create custom bindings. (see this)

So, first thing I thought of, was how could I channel my inner-laziness in order to ~~abuse~~ utilize this.

So. I thought about it for a while, and I had a “Switch” statement floating in my head for a while until I ran across a post from Elijah Manor about a kind of strategy pattern in JavaScript.

I thought it was awesome. But even after reading the eval statement disclaimer, I’m still a little uneasy about using it….

YUCK!!

Regardless, I’ll let you be the judge. Here’s a rough excerpt of what I’m talking about.

HTML:

   1: <button data-bind="jqui: button">BUTTON OF AWESOME</button>

JavaScript:

   1: ko.bindingHandlers.jqui = {

   2:     init: function (element, valueAccessor, allBindingsAccessor, viewModel) {

   3:         awesome.handleJqui(element, valueAccessor);

   4:     }

   5: };

6:

   7: (function () {

8:

   9:     function getJquiMethod(element, method) {

  10:         // EVIL DON'T LOOK AT IT!

  11:         return eval("setJqui" + method() + "Element");

  12:     };

13:

  14:     var setJquiButtonElement = function(element) {

  15:         $(element).button();

  16:     };

17:

  18:     var awesome = {

  19:         handleJqui: function(element, methodCall) {

  20:             var fnc = getJquiMethod(element, methodCall);

  21:             fnc(element);

  22:         }

  23:     };

24:

  25:     window.awesome = awesome;

26:

  27:     var viewModel = {};

  28:     ko.applyBindings(viewModel);

  29: })();

This allows me to extend at will with functions like

   1: var setJquiDatepickerElement = function(element) {

   2:     $(element).datepicker();

   3: }

Which then allows me to call simple stuff like

   1: <input type="text" data-bind="jqui: Datepicker" />

Or…Lets get crazy… Let’s say we use the full power of KnockoutJS setup extra parameters to be passed in. Then let’s take that a bit further, and if we’re using ASP.NET MVC 3, we setup some helper methods to create this things for us. Then we can simply make calls like:

   1: @Html.DatePickerFor(a => a.BirthDate)

Cheating?! I think so. But time saver? Definately. My question is, is this too much of a hack? My problem primarily focuses around the eval call, in addition to the current method if extensibility with these calls.
You be the judge! As for me, the project I’m working on right now is small enough that I’m not caring right now.

Worst case, I hope you learned something!

-Jeff

More T4 Template Happiness!

Jeff Sheldon — Sun, 05 Sep 2010 17:18:07 GMT

So this is another post about T4 templates. But not just ANY T4 templates, Preprocessed Text Template’s (oooooh, ahhhhh)

Long story short, these are templates you can embed in an application to execute at runtime rather than at design time. There are some limitations compared to regular T4 templates, but needless to say, it sure makes generating code a breeze.

Back Story

I have this project I needed to work on that involved generating code from an Xsd. This Xsd changed often, so I created a project that did it for me because I’m lazy. So here’s how I did it.

1. Created a Console Application that took some parameters, namely, the string value for the namespace, the file location for the output dll, and the file location of the input Xsd file.

2. Inside of the project that used this file, I added a pre-build event that executed the generation of the dll.

3. Profit!

So here’s a little bit on how I went about the code generating console application.

First off, I do a lot of Xml manipulation, parsing, etc at work. But, like I said before, I’m lazy. I prefer to do my Xml work in C#. So in order to process an Xsd I (in my opinion) cheated. I created a set of classes that allow me to simply deserialize the xsd into a class.

Notice XsdBase, there’s not much to this, it’s just a base class created to handle Xsd element types that have annotations, maxOccurs, and minOccurs. It’s mostly there for extension method purposes.

Now with this in place, I can take the Xsd path, and simply deserialize it to the XsdSchema class. yay!

        1: public static XsdSchema Parse(string filePath)

       2: {

       3:     var document = XDocument.Load(filePath);

       4:     var schema = Parse<XsdSchema>(document.Root);

       5:     schema.SetParent(null, null);

       6:     return schema;

       7: }

       8:  

       9: public static T Parse<T>(XElement element)

      10: {

      11:     using (var sr = new StringReader(element.ToString()))

      12:     {

      13:         using (var r = new XmlTextReader(sr))

      14:         {

      15:             var s = new XmlSerializer(typeof (T), "http://www.w3.org/2001/XMLSchema");

      16:             s.UnreferencedObject += (sender, e) => Console.WriteLine("Unreferenced Object: {0}", e.UnreferencedId);

      17:             s.UnknownElement += (sender, e) => Console.WriteLine("Encountered an unknown element on line {0}: {1}", e.LineNumber, e.Element.LocalName);

      18:             s.UnknownAttribute += (sender, e) => Console.WriteLine("Encountered an unknown attribute on line {0}: {1}.{2}", e.LineNumber, e.ObjectBeingDeserialized.GetType().Name, e.Attr.LocalName);

      19:             s.UnknownNode += (sender, e) => Console.WriteLine("Encountered an unknown node on line {0}: {1}", e.LineNumber, e.LocalName);

      20:             return (T) s.Deserialize(r);

      21:         }

      22:     }

      23: }

So now I have some T4 template, and some classes I can use with it, Now what?

Well, I start off by adding two parameters to the top of my T4 template for passing in some information.

       1: <#@ parameter name="FilePath" type="System.String" #>

       2: <#@ parameter name="Namespace" type="System.String" #>

And I use them like so:

   1: var xsdSchema = XsdSchema.Parse(Session["FilePath"].ToString());

   2: var ns = Session["Namespace"].ToString();

Now my T4 template has access to those files, and it can do it’s thing. But wait, how do I pass that into the T4 template in the first place?
Well I did it like this!

   1: var codeGen = new ClassGenerator

   2:             {

   3:                 Session = new Dictionary<string, object>

   4:                                                 {

   5:                                                     {"FilePath", xsdPath},

   6:                                                     {"Namespace", ns}

   7:                                                 }

   8:             };

9:

10:

  11:             var code = codeGen.TransformText();

And now the code variable has all my generated code in it. Neat!
So that’s pretty much it. I’ve attached the project for you so you can see the in’s and out’s. Keep in mind though, it’s not quite production ready. Overall it was written in a bit of a hurry, so I think there are some unused methods and cheesy code hacks in there.

Also, it won’t necessarily work for ANY xsd. I tried to make it someone generic, but you might need to modify it some to work with your specific Xsd (I did).

Hrm, I think that’s all of the disclaimers I need.

Attachments: GenerateFromXsd.IV.zip

Entity Framework – T4 Template Happiness

Jeff Sheldon — Sun, 05 Sep 2010 16:53:52 GMT

I was going to make this one long post, but there’s just too much to cover. I’ll start with this one talking about the new Entity Framework changes and my hacks to use them my way.

Disclaimer: I got the base concept of how I do things from someone else, but for the life of me I can’t find the blog post I found months ago that outlines this. I’ll come back and update it once I find it, I’m pretty sure it was posted right before the EF 4.0 was released if that helps anyone find it.

Ok, so, back to my way.

When using the new Entity Framework features, I almost always use the new Self Tracking Entities by using the Context Menu in the Edmx designer and selecting “Add Code Generation Item”.

One of the major reasons I love the new STE templates is the separation of my domain objects from the data context. So let me backup by saying I almost always setup my project structure like so:

Now, once we’ve added the STE project we’ll have 3 files created. The Edmx, the Name.Context.tt, and the Name.tt. The Name.Context file holds the ObjectContext class which manages the connections, adding, editing, etc. The Name.tt file handles the generation of all your domain objects.

So the first thing I’ll do after doing that, is add a DomainObjects class library project. Create my generated folder (because the contents is generated) and add the Name.tt file “As a Link” I also select the original file and empty the “Custom Tool” property.

This causes all of my domain objects to be created in a separate project. (Yay!) Once that’s done, there are a few tweaks I still need to make. Because my files are in the generated folder, they’re namespace will also end with “Generated”. I can’t have that, so I edit the property “Custom Tool Namespace” on each file so that it makes sense.

So in the end, we’re left with a project structure somewhat like the screenshot above. Take note of the “Partials” folder. that’s where I stick my partial classes for my domain objects, this holds customized metadata like the following for the Agent class.

        1: using System.ComponentModel;

       2: using System.ComponentModel.DataAnnotations;

       3:  

       4: namespace Pax.DomainObjects

       5: {

       6:     [MetadataType(typeof(IAgentMetaData))]

       7:     public partial class Agent

       8:     {

       9:     }

  

    public interface IAgentMetaData

    {

        [StringLength(50)]

        [Required]

        [DisplayName("First Name")]

        string FirstName { get; set; }

  

        [StringLength(50)]

        [Required]

        [DisplayName("Last Name")]

        string LastName { get; set; }

  

        [DataType(DataType.PhoneNumber)]

        string BusinessNumber { get; set; }

  

        [DataType(DataType.PhoneNumber)]

        string HomeNumber { get; set; }

  

        [DataType(DataType.PhoneNumber)]

        string FaxNumber { get; set; }

  

        [DataType(DataType.PhoneNumber)]

        string MobileNumber { get; set; }

  

        [DataType(DataType.EmailAddress)]

        string EmailAddress { get; set; }

  

        [DataType(DataType.Url)]

        string WebPage { get; set; }

  

        [DataType(DataType.MultilineText)]

        string Notes { get; set; }

    }

}

At this point we’re all setup. But wait, what if we want to customize the code generated by the T4 template? Well go right ahead, I do it all the time. But one thing that has always bugged me in the past, is I need to go and modify this every time I start a new project. Well not any more! Introducing the “Common” folder.

What I did was took a generic project and did the steps above. I then took the T4 templates and modified them the way I like them, for example, auto adding the StringLength property, auto adding the Using statement for my DomainObjects class etc. Next I wrapped them so that I could call them as a function so that I could include them, rather than execute them directly. Then I put them in the Common Folder like so:

I’m not sure if I need to include the EF.Utility.CSv2.ttinclude or not, but I put it there anyway. So now, my Name.Content.tt and my Name.tt files simply include them. The code for each looks like this:

Pax.Context.tt

       1: <#@ include file="Common/Context.tt"#><#

       2: BeginCode(@"Pax.edmx");

       3: #>

       4:  

       5: <#+

       6: string GetCustomUsings()

       7: {

       8:     return "using Pax.DomainObjects;";

       9: }

      10: #>

Pax.tt

       1: <#@ include file="Common/DomainObjects.tt"#><#

       2: BeginCode(@"Pax.edmx");

       3: #>

There are two huge benefits to this.

1. At work, I often use multiple Edmx’s for a project. I’m not going to explain why, needless to say, if my T4 templates are setup like this, then any modifications I need to make to the main template, automagically get applied to every template that implements them.

2. When I create a new project, I can copy this setup into it, and I’m off and running with all of my normal customizations, without having to dig through the created template to make the changes.

I’m not going to post the entire contents of my Context/DomainObjects templates, but I have them attached for your use. Keep in mind, they’re not changed drastically, I mostly just made some tweaks, and then wrapped the primary code generation portion in a method called BeginCode that accepts an input file. I also added a virtual method so you can auto include using statements. That’s about it.

Hope you find this useful!

Attachments: Custom.T4.SelfTrackingEntities.zip

Blog Updated…

Jeff Sheldon — Sun, 05 Sep 2010 15:49:56 GMT

Well I finally got around to updating my blog to the new version of Subtext.

Big thanks to the whole Subtext team for a smooth upgrade process. A short video by Phil Haack really helped the process a lot. Not to mention the Subtext Upgrade Tool.

Now it’s time to put up some code related blog posts!

Funk!

Jeff Sheldon — Sat, 28 Aug 2010 00:23:23 GMT

Yeah, I’ve been in a bit of a funk. That’s MOSTLY why I haven’t posted lately. The other reason I have (that I’ll admit) is that I have this issue with other people reading my stuff. I mean, I really want to blog. Hell, I wouldn’t mind it simply to have a record of things for MYSELF (screw you guys). But I can’t seem to get over this issue of other people criticizing me.

Actually, that’s not 100% accurate. If people have suggestions, or alterations I can deal with it. But if I post up a solution I’ve found, and people do nothing but point out how wrong I am, that would bug me. Honestly, I don’t know why, I think I have really good ideas. That’s not true, I do have an idea… see I’m 100% self taught. I find a problem, and I figure out a solution. I read a lot about best practices, patterns, etc. And I’m constantly looking for better ways. I do a decent job of reading other peoples ideas, and adapting them to my way of doing things. I’ll admit, my first time through, I’ll copy the code. But that’s only because when I copy it, I learn it. I understand what it’s doing. And then I delete it, and do it my way. That’s why I never copy files into my solution, I read them and write them. I follow what their code does, and then apply it.

Anyway, enough of my drama. I’m actually going to post 2 other blog posts after this about my ideas, so we’ll see how that goes.

Hopefully, if I post more of my ideas, the more I do it, the less scared I’ll get…right? (Agree with me, it’ll help)

Dilemma’s and Ideas…

Jeff Sheldon — Fri, 18 Sep 2009 21:33:59 GMT

While I was cruising The Morning Brew this morning, I came across Rick Strahl’s implementation of CodePaste.net. Which by coincidence was exactly the kind of thing I was gong to create with KodeBits.com.

Now I’m not bitter, but it does suck to find out not only that an idea you’ve come up with has already been done, but to find out that it’s been done well. I mean, CodePaste.net is hot. So now the dilemma, do I come up with a new idea for the KodeBits.com domain? Do I continue on and just release it as open source, making it a learning exercise? Or just throw the project away and come up with something new? Who knows!

I mean, really, in today’s day and age, ideas that haven’t been done are hard to come by. Even ideas that have been done poorly in the past, are tough to find. I suppose it’s something I’ll need to sit and ponder for a bit. We’ll see. But for now, I think I’m going to shelve the project and look for alternatives.

KodeBits Progress…

Jeff Sheldon — Fri, 18 Sep 2009 02:13:33 GMT

Well progress is pretty good actually. I’ve got a basic framework done. And a decent layout established. It’s not fantastic, but hey, I never said I was a designer.

Only had a few hours each night to work on it, so it’s not going as fast as I’d like, that, and I’m never 100% happy with my end result, so I keep refactoring to clean things up.

I’ve been trying to put all of my “Logic” into a separate layer. Make the controllers aware, but dumb. The issue there, is that it’s been pushing my business logic into my Service layer, and I don’t think I like that. I think I’ll need another layer in between.

So I’ve been tossing around the idea of making KodeBits open source. I have no intentions on selling it or anything, maybe some adsense on there or something, so that’s not my concern.

I have two fears.

1. This would be my first open source app. And it fears me to put myself out there like that. It’s hard enough writing to a blog that no one reads, I think I’ll fall out of my chair when I get my first comment.

2. I try to make my applications secure, but I’m all by myself here, and I make mistakes. I’d hate to make it easier for someone to hack my site because I leave the source out there for anyone to look at.

Oh well, I’ll think about it…

So I’ve got my OpenID Authentication setup the way I like. And a basic flow for initial authentication, but it still needs work. I added a “Credits” section too..Only fair because I’m using other peoples stuff too. i.e. DotNetOpenAuth. I also feel I need to throw some serious credit to the guys over at stackoverflow. It feels like I’m borrowing from the “Feel” when you’re over there. Think I might have to send an email to them to make sure I don’t piss them off.

Oh well, off to bed!

Oh yeah….

Jeff Sheldon — Sat, 12 Sep 2009 22:31:10 GMT

I forgot a couple of things I wanted to say…

Firstly, it’s been a while since I updated Subtext, so I went ahead and did that. And just in case you’re as dumb as I am, late me save you a few minutes by informing you to make sure you don’t copy up the web.config blindly. Oh yeah…there was 5 minutes of my time wasted digging around for the connection string to the blog’s database so I could put the site back together…Good times….

But back to KodeBits. I wanted to touch on my reasoning behind this.. I’ve been playing around with ASP.NET MVC for a little while now, and I’ve been really looking for a site to build with it. And now that ASP.NET MVC 2 is on it’s way, I finally figure something out. The technologies I’m using are:

SubSonic AND Entity Framework (That’s right both)
ASP.NET MVC 1.0 (Will upgrade to 2.0 once that’s in VS2010)
Structure Map – Don’t know how I got along without this..
A whole lot of jQuery love

Yeah, I’m using a simple repository pattern, and I wanted to have two different repository types built off of my Interfaces. Why? Cuz I can. I know it’s extra work, but I like the idea of being able to flip between two for no reason whatsoever. Plus I wanted to show a colleague the benefits of the repository/interface approach.

Hrm, ok I think that’s it for real this time.

Blog? What Blog?

Jeff Sheldon — Sat, 12 Sep 2009 21:48:48 GMT

So I put “Stylez” or whatever on hold. I re-read Rob Conery’s post and put a little more thought into it. I decided a “Blog” isn’t something I want to write, at least right now. But I did decide on something that I’ve been working on.

No details yet, but what I will say is this.

I registered the domain KodeBits.com
Layed out my initial design.
Setup my basic Layers
Setup OpenID authentication using DotNetOpenID (Thanks to Andrew Arnott)
Setup a Logo (See below)

I’m pretty set now with what I want to do. I’ll give you a clue though, my inspiration came from this post from Drew Miller about the release of Color Code 1.0.

Also, I’ve started working recently with Dario Solera on ScrewTurn Wiki. IMO one of the best pieces of Wiki software out there. Dario put’s a lot of effort into it, and I think it shows. Not to mention it’s free, and open source.

Ok that’s enough, back to work!

Introducing Stylez

Jeff Sheldon — Sat, 15 Aug 2009 18:58:12 GMT

Since this engine is for me, and I don’t really feel like fleshing out a super cool name for it like Subtext, or Blogger, I think I’ll just simply call it Stylez.

Database Design

I have to start with my database design and work my way up, I just find it easier that way. I’m using Sql Server 2005, simply because that’s the version I still have installed, and that’s the version my host provides me. I threw together a simple design, that I can easily expand on later. See below:

This gives me just about everything I need right up front, and allows for easy expansion in the future. Now to create and setup my project.