Tuesday, November 21, 2006

Although I love Xaml and the declarative person it makes me want to be, I feel even more strongly about fearless refactoring. If I fear renaming properties or moving types around, I do not refactor. And if I do not refactor regularly, my code begins to smell bad, which is a sure way to get my project featured the one place I do not want it ;-)

So, I want to refactor, but Xaml makes me reluctant to do so. We do not set bindings in code behind, but we declare them (which I think is 'good') in Xaml. Visual Studio doesn't search Xaml files for binding-paths. And so I'm left in the dark about what impact my refactoring will have. Furthermore, binding-errors do not throw exceptions, but fail gracefully, leaving a naive unittest none the wiser.

I've tried to catch the RoutedEvent 'Binding.Error' on a higher level, but it doesn't propagate.
Nor does the LoadedEvent of controls, if the control does not explicitly call some Loaded eventhandler. In this approach I thought I would be able to catch the loaded event of the control while they are being put on the screen and register their binding to be checked later. If all your controls in question do declare a Loaded handler, then you could use something like this:

EventManager.RegisterClassHandler(typeof(Control), Control.LoadedEvent,
(RoutedEventHandler)delegate(object sender, RoutedEventArgs e)
{

   // do your thing, throw an exception to let the unit test fail perhaps!
}, true );

But, like I said, this class handler will only fire if the control is already going to another Loaded event prior to this. Bummer.

Another approach would be to write a visual tree walker and question all the bindings in the screen about their status (a property of BindingExpression). This could be some trouble, but should be very do-able.

I've opted for yet another approach. I was using trusty Reflector to see how bindings work and discovered that binding errors are always shown in the output window. After some searching, it seems that even if you do not have any trace sources declared in your app.config, the visual studio debugger always switches the System.Windows.Data trace to the 'Warning'-level. And the warning level will trace a databinding error of code 35 if a binding is in error!

Well, quite an obvious solution then is to create your own trace-listener class and registering it in the app.config. To get it to work, your unit test will have to do a refresh of the Tracesources to get the traces to work: PresentationTraceSources.Refresh();

The Tracelistener:

public class UnitTestTracer : TraceListener
{
public override void Write(string message)
{
  // throw your exception to make trace fail!
}

public override void WriteLine(string message)
{
  // throw your exception to make trace fail!

}
}

And the app.config:

 

<system.diagnostics>
<sources>
  <source name="System.Windows.Data" switchValue="Warning" >
<listeners>
  <add name="unitTestListener" type="UnittestTestWPF.UnitTestTracer, UnittestTestWPF" />
</listeners>
</source>
</sources>
</system.diagnostics>

 Simple, yet effective. The more I think about it, the more I like the approach!

Tuesday, December 18, 2007 4:27:22 PM (Romance Standard Time, UTC+01:00)
Thanks Ruurd this is some really good stuff
Tuesday, December 25, 2007 6:35:06 PM (Romance Standard Time, UTC+01:00)
Hi there,

I did a similar post where I created a very small library for unit testing WPF (mainly 1 class :) ). Have a look at it and tell me what you think....

http://www.codeproject.com/KB/WPF/unittestingwpf.aspx

Regards
Marlon
Thursday, December 02, 2010 12:28:03 PM (Romance Standard Time, UTC+01:00)
As the sole of vibram five is surely brought forth in harmony with the human feet type. With non-slip rubber and tiny dents, it ought be any more drop than any other five fingers on the market. Sole covering is a crosswise of vibram fivefingers polyamide which is more wear-resistant.Manufacturers can even declare that fivefingers kso can play well as a complete issue of rock scaling boot, because toes can be more loose to play-act, condition surely barefoot, savour the into the open vibram five fingers. Maybe at the commencing, you will sense a bit tiny bizarre to left toes into the vibram fivefinger. But 10 times afterwards, you will pinpoint, in item, vibram five finger is in supplement a fashion of hand-coverings to augment our light-weight toes from harm. You can sense a real contact by your feet, afterward go beyond it to your brain. Then you can be more flexible manipulate of your feet.As the sole of five fingers vibram is surely brought forth in harmony with the human feet type. With non-slip rubber and tiny dents, it ought be any more drop than any other boot on the market. Sole covering is a crosswise of polyamide which is more wear-resistant.Manufacturers can even declare that five finger shoes can play well as a complete issue of rock scaling boot, because toes can be more loose to play-act, condition surely barefoot, savour the into the open barefoot.
novel fashion of boot seemed in the world, that is five finger shoes. It is just like a couple of hand-coverings for feet. And it has more portions for your health.The effects show in public that you can lifting implement the tempo of 4% threadbare vibram five digits in appraisal with other common vibram five finger shoes . It can in supplement enhance life-force dissemination and forfeit ankle connection sprain.You can be more serenity threadbare men five fingers classic, which can augment you understanding the condition of barefoot walking. It can augment to unwind your body, but in supplement mood.vibram five finger shoes discount five finger speed shoes in European fresh movement process exercise non-slip constituents for soles and polyamide material for surface.
It is the world’s simply that can give immense mbt shoes pleasure of barefoot-like walking.Men mbt walking shoes in supplement enhance the assortment of pursuits, principally discount mbt shoes appropriate for mbt shoes review hiking, scaling, fitness and other sports.They are absolutely mbt shoes sale favourable your health.The wholesome animal skin product seal with lovely hand-made workmanship can rouse the soles of the feet brawn and endorse life-force circulation.There are in supplement five fingers kso mbt footwear shoes to choose. Just draw seal to divulge more and understanding the bizarre feeling.http://www.fivefingersale.com/
Thursday, December 02, 2010 12:34:14 PM (Romance Standard Time, UTC+01:00)
Did you know that Skechers Resistance Runner has come out with a new line of Mens Skechers Resistance Runner? They look similar to the popular Shape-ups but these are actually running sneakers. The new Womens Skechers Resistance Runner retail for about $150. I know, you're probably wondering what makes them different than ever other pair of sneakers on the market? Let me break it down for you. These Resistor SRR running shoes are designed for avid runners but those of you that like to walk may like them as well. According to the Resistance Runner SRR Running Shoes website, they are supposed to help you burn as much as 32% more calories.Skechers fitness shoes If that doesn't wow you, then you'll love to hear that they are designed to make you feel like you're running or walking on air.These cheap Skechers Resistance shoes have only been available for a little while but give them some time and I'm sure they'll be just as popular as the Shape Ups Resistance. But you tell me. Do you think that these Resistance Runners will become a hit? Would you try them? Sound off in the comment section below.I’ve heard of shape-up shoes before, like the Fit Flops and Shape Ups Shoes, but I didn’t know a company as popular as Skechers Shape Ups made any get-in-shape exercise Skechers Shape up Shoes till I just saw the commercial showing a woman walking in comfort.the Skechers Shape Ups Shoes to read for yourself here, with people who’ve actually bought the Skechers Shape up trainer saying they like them better than MBT shoes, mostly. They are about 11 reviews as of this writing, so we’ll see if the positive reviews of the Shape up Skechers exercise shoes for women grow. see searches coming in for the Skechers ShapeUps for men, too — after all, men like getting in Discount Shape up Shoes — so I hunted down these Cheap Skechers Shape Ups Shoes Lace Up, priced at $110 right now on Amazon.Those shape ups outlet for men running? Skechers Womens Shape Ups — I guess you can run in them, huh? — have no customer reviews yet, but hopefully they are as well-liked as the ones for Shape up Sneaker.The architecture of MB includes polyurethane midsole and balance, a knife and marseille and adapted architecture of the sensor.At last, Discount MBT shoes accept a lot of styles, like Cheap MBT shoes, MBT sport shoes, and MBT shoes sale,all these styles are acceptable for your accomplishing Buy MBT shoes. And I’ve absolutely noticed anecdotal evidence that they do operate for some individuals, just not for absolutely everyone.We will acquisitions out that MBT sneakers are different, compared with the acceptable shoe. Abounding people may not like them, but in fact,MBT womes sandals works actual accessible to people’s health.

Comments are closed.