Randoom a Michael Friis production

ASP.Net MVC Layar layer, ghetto-style

Layar is a really great meta-app for iPhone and Android that lets you see a lot of third-party geo-based augmented reality layers on your phone. A “layar” consists of a JSON webservice that provides Points of Interest to users. There is HttpHandler implementation available for .Net, but the Layar specification is so simple (in the [...]

Dynamic Sitemap with ASP.Net MVC (incl. geo)

Here is how I generate sitemaps using the XDocument API and a ContentResult. The entries are events that come out of the EventRepository, please substitute as needed. Note that it would be vastly more elegant to use ActionLinks in some way. Note also that the first entry is a link to a Google Earth KMZ [...]

Linq-to-SQL, group-by, subqueries and performance

If you’re using Linq-to-SQL, doing group-by and selecting other columns than those in the grouping-key, performance might suffer. This is because there is no good translation of such queries to SQL and Linq-to-SQL has to resort to doing multiple subqueries. Matt Warren explains here. I experienced this firsthand when grouping a lot of geocoded events [...]

C# and Google Geocoding Web Service v3

Need to geocode addresses using the v3 Google Geocoding Web Service? There are some good reasons to choose the new v3 edition — most importantly, you don’t need an API key. You could use geocoding.net which — at the time of writing —  has some support for v3. I decided to hack up my own [...]

Webcam face detection in C# using Emgu CV

Some time ago I wrote a post on how to do face detection in C# using OpenCV. I’ve since begun using the Emgu CV wrapper instead of opencvdotnet. Emgu CV is much better, in active development and it even runs on Mono. Two gotchas:

You don’t have to install OpenCV, but instead have to copy the [...]

Smuggling exceptions out of try-catches with IEnumerable

The code in this post is from a talk by Erik Meijer, I claim no credit.
Take a look at this screenshot:

Pretty wacky huh? Visual Studio has broken into debug mode even though the division is clearly wrapped in a try-catch. Take a guess at what’s going on before reading on.
Here’s the full code listing:
static void [...]

CRMMetal and LINQtoCRM

As you may know, Microsoft introduced many-to-many relationships in version 4.0 of Dynamics CRM. Unfortunately, querying these relationships is not supported through the general web service entities as the intermediary entities are not exposed. Fetch XML works fine however (and don’t forget this great hack to generate FetchXML). The missing entities meant that LINQtoCRM didn’t [...]

Using WCF to power Facebook feedstory forms

UPDATE: I think facebook has changed the API so that links in full stories have to be split into src and href parts.
Several parts of the Facebook developer API requires application developers to furnish JSON web services that feed data to various actions. These include feed forms (“I want to stick something on my wall”) [...]

Facebook signature generation in .Net

While the Facebook Developer Toolkit handles most of the needs of your average Facebook application, there is not support for the Post-Remove stuff that happens when users decide to remove your application. When your application is removed by a user, Facebook submits a “Post” in the the general direction of a url you’ve specified. The [...]

Facedectection in C# with less than 50 LoC

I’ve been mucking around with face detection a bit lately. Here’s a short guide to getting face detection running in C# in a short amount of time.
UPDATE: Recommend EmguCV for C# wrapping OpenCV, read the updated guide.
I’ve identified two free computer vision libraries that do face detection:  Torch3vision and OpenCV(I’m sure there are plenty more, [...]