Archive for 2010

A Parser for Formatted Text in WPF / Silverlight

November 5th, 2010

I finally got round to implement on-the-fly text formatting for Sketchables, which will  allow you to define text formatting while typing (similar to wikis or forum posts). Sketchables will parse such strings and format them on the fly for you:

the star renders *bold* text

I didn’t rely on regular expressions here, but wrote a simple forwarding parser to process markup text. As it makes a pretty neat tool, I extracted it into a little sample app that shows a possible use for it. The presented implementation just creates nested text blocks, but you should be able to easily adjust it to your needs.



Latest Update:  2010.11.07 – Fixed issue with single character chunks.

Download Sample Application

Back in Switzerland

September 3rd, 2010

The blog (and myself) has been dormant a while – I’ve been literally working my *** off (doing over 600 hours in just two months isn’t too healthy) and have rewarded myself by travelling the US for three weeks. However, I’m back in Switzerland now and will try to reply to pending posts and questions asap (read: once I get rid of my current sleep deprivation), along with an update on Sketchables.

Author: Categories: Personal Tags:

Sketchables 0.9 – Public Preview Release

July 20th, 2010

I wanted to officially release Sketchables weeks ago, but business just got in the way – and it turned out that my plan to just working at night / on weekends didn’t work either because, well, business got in the way there, too.

However, my deadline ends in little more than a week (and I’ll have quite some time at my hands in August), so I’ll be able to finally package Sketchables, record some more videos, and of course add a few goodies. For now, I’ve prepared a preview release of the package which already works quite solid:


Sketchables Preview


If you compare this package to the contents in the YouTube video, the most prominent addition is built-in navigation support which gives you point-and-click navigation, and allows you to trigger other actions for a Sketchable’s items:

(Click on screenshot to show in full size)



As always, critical feedback is appreciated – happy sketching! 🙂

Author: Categories: Open Source, Silverlight, Sketchables, WPF Tags:

Announcing Sketchables – Rapid Mockup Creation with SketchFlow

May 24th, 2010

SketchFlow is a great addition to Blend, but I was missing the ability to create quick mockups of user interfaces. I’m a huge fan of productivity tools such as Balsamiq, and I was sorely missing its ease and speed in SketchFlow.

Meet Sketchables. Sketchables is a simple framework complemented by a set of controls that allow you to quickly create common controls in a matter of seconds. Here’s a screenshot from one of the samples, which was created in just a few minutes:



…and here’s a complementary recording that shows how the above mockup was created:




Sketchables will be free software, requires Blend 4 RTM and fully supports both WPF and Silverlight SketchFlow projects. Version 1.0 is approaching completion, so I hope I’ll be able to release it as soon as Blend 4 goes live.

Still time for you to slip in some last-minute feature requests though 😉

An Abstraction Layer for Temporary Data in .NET and Silverlight

April 15th, 2010

Up until now, I’ve dealt with temporary data in my .NET applications using local files and FileInfo instances.  This worked just fine – until I needed a solution that works under both .NET and Silverlight.

The problem: In Silverlight, you can’t just create a temporary file on the file system for security reasons. Instead, there’s the concept of isolated storage that provides you with the means to store data in files and directories. The API is very similar to working with the local file system, but it doesn’t use the FileInfo class. As a result, I needed to get rid of the (proprietary) concept of FileInfo in my temporary file handling and came up with a simple yet generic solution.


Download Sample Project


Here’s a sample usage of the API. This code transparently creates temporary storage, and works in both .NET and Silverlight:

private void Foo(ITempStreamFactory factory)
  using (Stream stream = factory.CreateTempStream())
    //write to the stream, read from it

  //once we get outside the "using" block, temporary data has been discarded


The snippet above relies on a factory of type ITempStreamFactory that returns a simple Stream instance. I do not need to know anything about this returned stream – it’s the factory’s responsibility to return a Stream instance that will clean up after itself once it is being disposed.

Read more…

Author: Categories: C#, Silverlight Tags: ,

A Custom Text Encoding Generator For Silverlight

March 30th, 2010

Unlike the .NET platform, Silverlight only provides two text encodings out of the box: UTF-8 (UTF8Encoding class) and UTF-16 (UnicodeEncoding class).

Accordingly, if you find yourself in a situation where you need to encode or decode data with another encoding (e.g. iso-8859-1), you’ll have to write your own Encoding class (or delegate the work to a server-side service).

I found myself in this exact situation yesterday, and came up with a little tool which automates the process. The Encoding Generator is a WPF application which takes the name or code page of a well known encoding, and generates source code for a custom Encoding class which compiles under Silverlight.


Get Source Code


Get Compiled Executable

Current version: 1.0.0, 2010.03.31, requires .NET 3.5 SP1 or higher

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How Does It Work?


Specifying the Encoding

In order to specify the encoding you want to use, you can either enter the name or numeric code page of a well-known encoding. As soon as you enter a valid value, some information for the encoding is being displayed in the right hand border you can see on the screenshot.

As a sample for valid encoding names or code pages, here’s some values you can enter in order to tell the tool to generate an iso-8859-1 encoder (see screenshot):

  • iso-8859-1 (name)
  • latin1 (name)
  • 28591 (code page)
    A list of encodings can be found here.

Fallback Character

The tool gives you the option to specify a fallback character value, which is used as a default in case a character or byte value is being processed during encoding/decoding. In case you don’t specify the character, the encoding class will crash at runtime should it receive data that cannot be properly encoded or decoded.

Single-Byte Encoding Limitation

The generated class only works if a single byte can be translated into a single character and vice versa. Accordingly, if you try to generate code for an encoding that uses several bytes per (e.g. utf-8) character, the generator shows an error message.

Byte Range

You need to specify the byte range of the encoding. For example, ASCII supports only 128 characters, and therefore has a byte range of 128 bytes. Most other encodings support a byte range of 256 bytes, though. 256 is the maximum value that can be specified, as a single byte cannot deliver more values (the byte data type covers a numeric range from 0 – 255).


The generator also creates an NUnit test class that compares the results of the generated class against the original encoding. Accordingly, this test class is supposed to run in a regular .NET environment, not in Silverlight (if the original encoding that is used in the test was available in SL, you wouldn’t have to generate a custom encoding class in the first place…).


At runtime, the following is happening: Basically, the generator maintains mapping tables to do the encoding and decoding from characters to bytes and vice versa. Fore every request, it just looks up the translation tables for every supported character/byte value of the encoding.

The generator creates these translation tables on the fly in the form of a static array and dictionary.


The library doesn’t contain any performance tweaks and performs much slower than the built-in encodings that rely on all sorts of black magic. However, as long as you don’t have to encode or decode huge amounts of data, this shouldn’t be noticeable.

Here’s the results from my machine for 10000 iterations:

  • Encoding the whole character table to a byte array (256 characters)
    • 17 milliseconds with the built-in encoding
    • 94 milliseconds with the generated encoding
  • Decoding the bytes back into a string
    • 2 milliseconds with the built-in encoding
    • 46 milliseconds with the custom encoding