Thursday, February 12, 2009
Migration
Monday, February 9, 2009
My Day Job
This Dilbert strip sums up my day job pretty well.
I'll get to that File Uploader post that I promised soon...
Monday, February 2, 2009
Phoenix Silverlight User Group
Dave Campbell of Silverlight Cream has asked me to present at the next Phoenix Silverlight User Group meeting. If you are interested in Silverlight and live in the Phoenix-metro area, it is a great user group to join.
My presentation is titled "Using Silverlight and WCF to create a RESTful File Upload Utility". If any of those topics interest you, please come and join us! Source code will be provided on this blog in the days following the presentation. Hope to see you there!
Saturday, January 3, 2009
MIX09 10K Smart Coding Challenge
I entered a Zleek Silverlight application into the MIX09 10K Smart Coding Challenge. Please Vote for my entry by rating it 5 stars!
It is a very "lite" version of Zleek that contains only a single page where you can upload images, manipulate them using drag/rotate/scale, and save your layout. You can't share layouts with other users, but the application will remember your last saved layout.
The idea of the competition is to fit as much functionality in only 10KB of source code. Here's a snippet of what size constraints will make your code look like (note that my actual submission was all on a single line of text):
I should write code like this at work! I'm sure everyone would appreciate how easy to read it is! Anyway, it was fun putting together code completely at odds with my normal coding style. For you geeks out there thinking about entering, here is what I learned from the experience:
- var is your friend.
- Use lambdas where possible. The implicitly typed arguments are great for shaving off type names (just like var).
- LINQ extensions to IEnumerable and IList are great. ForEach and Cast will save you a lot of code especially when combined with lambdas.
- Use fields over properties. Remember that leaving off the access modifier will mark them private.
- Question every single framework call you make and whether or not it makes sense to encapsulate it. I ended up taking a bunch of the common ones and creating static methods that wrap the calls.
- If you have a function that takes multiple parameters of the same type, use an array declaration instead. (e.g. CalcDistance(Point a, Point b) becomes CalcDistance(Point[] p) -- and of course the actual function name should be trimmed to 1-2 characters)
- XAML vs. Code vs. external image -- In many cases, code is preferred over XAML. The obvious exceptions here is XAML that makes heavy use of Path.Data (code does not accept the shorthand notation, AFAIK). The code for downloading an image using WebClient is fairly small. Definitely worth looking at. Note that downloading remote XAML is frowned upon by the contest moderators and should not be used.
- Consider subclassing commonly-used non-sealed framework classes. Unfortunately, all of the common long-named classes I was using were sealed, so I couldn't do this... but I wanted to try and subclass framework classes that I used a lot so that I wouldn't waste space with the type name that often.
- Place all of your CODE in a single file so that you only have to take up space for "using" directives once. (Note: you might have to add some class assignment directives as well e.g. using Path=System.Windows.Shapes.Path when System.IO is also imported)
- Cleanup all of the whitespace. Remember special spacing rules like int[]a and int?a are valid and do not require spacing after the type name due to the non-alpha character.
Sunday, December 28, 2008
Consuming RESTful Web Services in Silverlight
Overview
The key points are:
- Creating a new Service Host Factory and Interceptor to support HTTP Verb tunneling, since Silverlight supports only GET and POST verbs.
- Issuing calls from a client application to the RESTful service (including Silverlight and Fiddler)
Here are my take-aways from the experience:
- The WCF Rest Starter Kit makes generating RESTful services extremely easy!
- The ADO.NET generated entity classes are declared as partial so that you can easily extend them with your business logic.
- You should create a separate Data Contract version of your entities in order to facilitate serialization
Step-By-Step
- Download the WCF Rest Starter Kit
- Create a blank solution and add the Microsoft.ServiceModel.Web project from the starter kit as well as the Agnition.Silverlight.Utils project into it.
- Create a class library for your ADO.NET Entities
- Create an Entity Data Model from your database
- Create partial classes for each of your entities that you wish to write business logic or create data contracts for. Ideally this will be in a separate class library project.
- Create a class library for your data contracts.
- Create a Silverlight class library for data contracts. You will add all data contracts here as existing links to your other data contracts library to facilitate code sharing between your .NET 3.5 and Silverlight 2.0 libraries.
- Optionally create Silverlight business entity classes (possibly in another library) for your Silverlight application.
- Create a Silverlight application that you will use as your client. Ideally you should create a separate ASP.NET web application linked to the Silverlight application for ease-of-testing.
Now we can start fleshing out the service and client. Let's start out by creating the service. Follow Rob's Post to walk-through creating your Service Host Factory and Interceptor. After that is complete, get started making the sevice more accessible to Silverlight.
- Remember those data contract libraries? Now it's time to flesh them out. For each entity, create a class with public properties for each piece of data you wish to expose. You can include relational properties this way as well. Here is an example:
- Provide a way to project your entity class into your data contract. The easiest way (syntactically) to do this is to create an operator that will allow you to project the entity class into your data contract type while using casting syntax. The following screenshot illustrates both creating the operator and using the cast syntax to perform conversions:
- Create a web service method using OperationContract and WebInvoke (or WebGet) attributes. Remember that to be truly RESTful, retrieval operations should use GET, inserts/updates should use PUT, deletes should use DELETE and appends should use POST. Response codes should be used effectively as well. Here is a GET example:
- Create a way to get the service URL into the Silverlight application. I like to use startup parameters. Here is how they are declared:
They can only be extracted in the Application.Startup event, so I like to create a Configuration class that gives strongly-typed access to my parameters later.
- Now we are ready to call the service and deserialize the result:
Sunday, December 21, 2008
Silverlight Extenders
Over the coming months before our release, I will be posting code snippets and libraries that I put together for Zleek that may be helpful for other Silverlight developers.
This first post is a combination of a few extenders that I put together:
- DragExtender: Adds mouse drag functionality to any FrameworkElement
- RotateScaleXtender: Adds mouse rotate/scale functionality to any FrameworkElement
- KeyExtender: Adds extra keyboard support, including handling of DOM events and extra keys
- FillContainerExtender: Automatically resizes the Silverlight application to fill its container.
Here is the running example.
The source code in the test harness is pretty simple. You declare an instance of the extender and give it a reference to the FrameworkElement you want to add functionality to, and the extender does the rest. There are extensibility points inside of the extenders that should make them useful for any application.
Here is the source code, and here's a snippet from the test harness showing example usage:
1: using System;
2: using System.Windows.Controls;
3: using Agnition.Silverlight.Input;
4: using Agnition.Silverlight.Controls;
5:
6: namespace ExtenderTestHarness
7: {
8: public partial class Page : UserControl
9: {
10: public Page() {
11: InitializeComponent();
12:
13: // Initialize extenders
14:
15: _fillContainerExtender = new FillContainerExtender(this.LayoutRoot);
16:
17: _keyExtender = new KeyExtender(this, true, true, true);
18: _keyExtender.KeyDown += new EventHandler<KeyCodeEventArgs>(KeyExtender_KeyDown);
19: _keyExtender.KeyUp += new EventHandler<KeyCodeEventArgs>(KeyExtender_KeyUp);
20:
21: _dragExtender = new DragExtender(this.DragMe);
22: _dragExtender.StateChangeStart += new EventHandler<StateChangingEventArgs>(DragExtender_StateChangeStart);
23:
24: _rotateScaleExtender = new RotateScaleExtender(this.DragMe, 0.75, 6);
25: _rotateScaleExtender.StateChangeStart += new EventHandler<StateChangingEventArgs>(RotateScaleExtender_StateChangeStart);
26: }
27:
28: private void FullScreenButton_Click(object sender, System.Windows.RoutedEventArgs e) {
29: // Toggle full screen
30: _fillContainerExtender.IsFullScreen = !_fillContainerExtender.IsFullScreen;
31:
32: // Toggle display of warning
33: FullScreenWarning.Visibility =
34: FullScreenWarning.Visibility == System.Windows.Visibility.Collapsed ?
35: System.Windows.Visibility.Visible : System.Windows.Visibility.Collapsed;
36: }
37:
38: private void KeyExtender_KeyDown(object sender, KeyCodeEventArgs e) {
39: // Demonstrates KeyCode event arguments Key and TextValue
40:
41: // Show which key was pressed
42: if (e.Key == KeyCode.Shift) {
43: MouseMode.Text = "Mouse Mode: Rotate/Scale";
44: }
45: else {
46: // Don't show message on shift, to prevent spamming while holding
47: KeysPressed.Text += e.Key.ToString() + " ";
48: }
49:
50: // Render the text
51: if (e.TextValue != null) {
52: KeyText.Text += e.TextValue;
53: }
54: else if ((e.Key == KeyCode.Backspace) && (KeyText.Text.Length > 0)) {
55: // Check for backspace
56: KeyText.Text = KeyText.Text.Substring(0, KeyText.Text.Length - 1);
57: }
58: }
59:
60: private void KeyExtender_KeyUp(object sender, KeyCodeEventArgs e) {
61: // Demonstrates KeyCode event arguments Key and TextValue
62:
63: // Show which key was pressed
64: if (e.Key == KeyCode.Shift) {
65: MouseMode.Text = "Mouse Mode: Drag";
66: }
67: }
68:
69: private void DragExtender_StateChangeStart(object sender, StateChangingEventArgs e) {
70: // Demonstrates how to cancel an event in order to combine two MouseMovementExtenders
71:
72: // If not holding shift, allow dragging
73: e.CancelEvent = _keyExtender.IsShiftDown;
74: }
75:
76: private void RotateScaleExtender_StateChangeStart(object sender, StateChangingEventArgs e) {
77: // Demonstrates how to cancel an event in order to combine two MouseMovementExtenders
78:
79: // If holding shift, allow rotate/scale
80: e.CancelEvent = !_keyExtender.IsShiftDown;
81: }
82:
83: private readonly FillContainerExtender _fillContainerExtender;
84: private readonly KeyExtender _keyExtender;
85: private readonly DragExtender _dragExtender;
86: private readonly RotateScaleExtender _rotateScaleExtender;
87:
88: }
89: }