Sometimes it happens that Xcode throws you an exception, and you don’t know why. How do you print the relevant Exception information?

To get more information, you can configure the debugger to break when any exception is thrown. Go to the Breakpoint Navigator and click the little ‘+’-button at the bottom. Then click “Add Exception Breakpoint”.

Add Exception BreakpointBut, in many cases, even then you don’t get the information you wanted when the Exception occurs. Add these commands to the breakpoint configuration to show the name and reason of the breakpoint. This should get you on the way to eliminate the error.

Breakpoint on all exceptions

po [*(id *)($esp+4) name] and

po [*(id *)($esp+4) reason]


This works when you are using LLDB by printing the name and reason of the exception in the command window. You can also execute those commands in the command window, but you have to make sure to select stackframe 0 first.

I’ve implemented a Filter to apply on text fields in ASP.NET Dynamic Data websites.

To use it: include the code in your project by putting it in the DynamicData\Filters folder. Then apply the filter to the field you want to enable filtering on using the FilterUIHint attribute.


public partial class Category
  class Category_MetaData
    public string Description { get; set; }

You have to manually trigger the application of the query filter by adding a button to the appropriate template. For example, add this to the List.aspx template:

in the code behind for that template:

protected void SearchButton_Click(object sender, EventArgs e)

If you want to see it in action, you can download the full sample code, which is based on the famous Northwind database on SQLExpress.

I got a lot of inspiration and help from msdn and this blog post to get to a decent implementation for this.

Like always I’ve compressed the code using 7-zip. The best compression tool. Ever.


ik heb meegedaan aan het wedstrijdje van microsoft, waar je het spel mastermind moest spelen. Ik deed er niet veel moeite voor, en vond geheel toevallig de juiste oplossing. Gissen en missen… Wonderbaarlijk. Ik dacht oorspronkelijk dat ik de juiste oplossing niet had gevonden, maar men heeft me erop attent gemaakt dat het me toch gelukt was, waarvoor dank! In elk geval een leuk spelletje dat je ook eens moet uitproberen. Interessant zou zijn om een algoritme te bedenken dat in zo weinig mogelijk pogingen steeds het juiste resultaat geeft. Veel succes ermee!

The video shows a prototype of a machine that is powered by the wind that reaches speeds higher than the wind, moving directly down wind.

DDWFTTW stands for Direct Down Wind Faster Than The Wind.

Every Windsurfer with a little bit of experience knows that this is impossible using just a stationary sail, because of losses due to friction, it is not even possible to go as fast as the wind, when moving directly down-wind. If you have an angle, it is possible to go faster than the wind using a modern sail.

Now how does this work? What you have to notice is that the turbine is not moving the wheels, but the wheels are moving the turbine, this means that the turbine is blowing in the direction that the wind is coming from. The wind pushes the cart forward, this sets the wheels in motion, which in turn sets the turbine in motion, which generates extra trust. Really cool and at first contra-intuitive. Don’t you just love engineering!!

This new-found knowledge will certainly buy you a beer at the bar, if you can lure the right people into a wager.