DotNetKicks.com : Stories kicked by Klaus

When PowerShell hash table magic backfires

Mon, 05 Jan 2009 07:37:57 GMT

We just made it through the holidays and I finally found time to write about the most annoying thing in PowerShell: Hash table semi-automatic, which can easily result in some subtle bugs. And all of that, just because the hash tables don't behave as I would expect. I assumed hash tables to be implicitly sorted by the keys using the Sort-Object cmdlet and to always stay hash tables and not get converted into arrays of Dictionary Entries or even a single Dictionary entry when piped into a Where-Object cmdlet. To workaround these strange defects you need to apply some unnatural constructs and roll your own select statements. It just doesn't feel fair to make your children call GetEnumerator() before they try to find today's window on their Advents Calendar.

Dear PowerShell Santa...

Wed, 17 Dec 2008 07:13:43 GMT

PowerShell has a great potential, but it needs professional tool support in order for it to mature. The current solutions are far too amateur. Here is my list of PowerShell improvements for Santa Claus

One PowerShell Script to download PDC2008 Videos, Code and PowerPoints

Wed, 10 Dec 2008 18:46:08 GMT

Yes I did it. I downloaded all 65,563,667,714 bytes and saved them as 407 files on my nice new WD Passport hard drive that I brought home from the PDC2008. And, yes I did it the old fashioned manual way: Right-Click on link and Save-As. But you don't have to do it. In this blog post I provide the metadata of all the files I downloaded and a PowerShell script that will help you automating the download process. Besides the PDC content you also get to a treasure trove of PowerShell scripting techniques ranging from dynamically generating Regular Expressions to loading meta-data form XML and CSV files.

Meta-Programming with PowerShell and Regular Expressions

Wed, 26 Nov 2008 16:29:37 GMT

I am almost done with my biggest PowerShell scripting project so far. The last feature that I implemented was a flexible pattern matching facility. I wrote a procedure that would try to filter out a set of file names based on the first letters and the extensions of the file. The possible name prefixes and extensions would be provided by string arrays that could contain zero or more elements. The challenge as always with PowerShell is to understand its type conversion magic. One approach to this is to use baby steps while morphing the static regex string to a dynamically built regex string. This progression and the result is captured in this blog post.

Set-Content -Encoding parameter matters, if the content says so...

Mon, 10 Nov 2008 16:08:31 GMT

I use a simple PowerShell script to replace some of the URLs in my blog post's html source before I publish them to www.tellingmachine.com. In my case the posts are stored as XML files. Usually I use Windows Live Writer to write my posts. I publish the documents for test purposes frequently during the authoring to the VisualStudio 2008 development web server that runs locally on my machine. Once the post is ready to put online, I take the XML file, run the PowerShell script against it and then copy it to my production server. Occasionally the XML files refuse to open in Internet Explorer after I ran the script. It took me few minutes to figure out why. Here is the story!

What is the coolest thing on the planet? - PowerShell

Tue, 14 Oct 2008 06:19:47 GMT

Walter and I gave a presentation at the WonderWorld 2008 conference in Las Vegas last week. To get many people exited about our talk, we asked customers what they think the coolest thing on the planet is. They thought first that this is a trick question, but we didn't keep them in the dark for too long. The coolest thing on the planet is: PowerShell

Converting a Generic List of Custom Objects & Property to a Formatted

Mon, 13 Oct 2008 05:18:58 GMT

Today I had the need to take a list of names from a returned list of Custom Objects, and convert one of its properties it to a string that included some HTML. This is nothing fancy, and pretty standard/simple but I thought I'd post about it anyway. Since I did not need a custom ToString() method here to convert all properties of my object, I just created a simple method to iterate through the list of objects and add one of the properties to the StringBuilder object which is ultimately being returned to give me the nice string with HTML.

Patching File System Trees with PowerShell

Fri, 29 Aug 2008 15:04:34 GMT

While working on a elaborate PowerShell script I needed to find a solution for the following problem: I wanted to do a string replace operation on a file system path name and have the resulting new string be reflected by the file system. For example the path name "C:\dogs\dog food\my favorites\hot dogs\Who let the dogs out.mp3" should be renamed by replacing "dog" with "cat". The resulting path name would be "C:\cats\cat food\my favorites\hot cats\Who let the cats out.mp3". Sounds easy, but how do I move the folders and files that are referred to in the path to their new locations? And even better, how can I do this recursively? This short blog post demonstrates two possible approaches.

Customization of PowerShell hash table merges

Wed, 13 Aug 2008 18:17:35 GMT

PowerShell provides the += operator to add one hash table to another hash table. By default this operation will result in an error, if both hash tables have at least one key that is common in both collections. In some cases you may want to have a more granular control. For example, you don't want to get an error, if not only the key, but also the value is common in both collections.

Finding missing and duplicate lines in text files using PowerShell

Fri, 25 Jul 2008 16:38:14 GMT

Every now and then I need to investigate bugs that get exposed because countable "things" are less or more than expected. In my special case I was dealing with an application that manages subscription handles to memory registers of programmable logic controllers (PLC). These programs are called Data Access Servers. Occasionally we get calls form customers reporting that the number of handles is less, or sometimes more than expected. The first step to debug this situation is to find out, which handles are missing or which ones are duplicates. This blog post describes how PowerShell's Compare-Object cmdlet makes this task, which used to be a pain in the "peep" now a piece of cake.

Extracting errors and warnings from a log file using PowerShell

Tue, 22 Jul 2008 18:01:53 GMT

This blog post shows a simple Powershell command that searches a log file for errors and warnings and adds the matched lines to either to the errors.txt file or to the warnings.txt files. It takes advantage of the most powerful operator in Powershell, which is the switch operator. In my example here I exported the log file from the Wonderware SMC logger.

Renaming a series of indexed files with Powershell

Thu, 17 Jul 2008 22:42:45 GMT

I love Powershell. I am only halfway through Bruce's book, but I am getting already a glimpse of its potential. I like especially the dynamic aspect of it. Creating and extending types on the fly is something that is quite exciting. Next I am looking to find a solution for my open issues with sorting hash tables. I think building a custom PSObject type with an integer NoteProperty and a NoteProperty that holds a FileInfo object might get me a few steps closer to solving the sorting challenge.

ASP.NET MVC preview release 4 - part 1

Mon, 14 Jul 2008 11:01:09 GMT

The ASP.NET MVC team is in the final stages of finishing up a new "Preview 4" release that they hope to ship later this week. The Preview 3 release focused on finishing up a lot of the underlying core APIs and extensibility points in ASP.NET MVC. Starting with Preview 4 this week you'll start to see more and more higher level features begin to appear that build on top of the core foundation and add nice productivity. There are a bunch of new features and capabilities in this new build - so much in fact that I decided I needed two posts to cover them all. This first post will cover the new Caching, Error Handling and Security features in Preview 4, as well as some testing improvements it brings. My next post will cover the new AJAX features being added with this release as well.

Debugging 101 - Measure, do your homework and think out of the box

Wed, 02 Jul 2008 22:10:45 GMT

Being confronted with an occasional bug in a complex system can be quite overwhelming. There are three disciplines that help you to stay strong: 1) Read and learn about your platform and how to debug it. 2) Use tools to quickly get the low hanging fruit. This might be enough in most of the cases to identify the bug. 3) Think out of the box and try to be creative. Build a model, play with it, break it and fix it. In the worst case, you won't have found the cause of the bug, but you learned at least something new about your software.

Blog Engine.NET1.4 Released

Tue, 01 Jul 2008 17:01:03 GMT

Blog Engine.net 1.4 has been released. more...

Introduction to Mocking with Rhino Mocks

Tue, 17 Jun 2008 14:01:09 GMT

A short screencast introduction to Mocking with Rhino Mocks

Introduction to Moq

Mon, 23 Jun 2008 17:01:04 GMT

In this post, I provide an introduction to Moq which is the newest of the Mock Object Frameworks. Moq is promoted by its creators as easier to learn and use than other Mock Object Frameworks such as Rhino Mocks and TypeMock Isolator.

MVC Storefront Part 14: Ajax With Shawn Burke

Wed, 11 Jun 2008 03:42:27 GMT

MVC doesn't have a PostBack model and has lost a lot of the drag/drop ASP.NET Ajax functionality that was provided with .NET 2.0. In this screencast I show you how can leverage the existing AjaxControlToolkit bits, as well as do a nice Ajax-powered asynchronous form post.

How to rename batches of files using .NET Regular Expressions

Tue, 10 Jun 2008 23:10:49 GMT

The tool that I am presenting here renames batches of files that have some kind of numerical index as part of their file name. It can rename the text before the index, it can shift the index numbers, give the files a new extension and add or remove leading zeros to and from the numerical index part of the file name. It uses Regular Extensions to parse the file names.

What a developer needs from their manager

Tue, 10 Jun 2008 16:16:03 GMT

I've a read a lot of articles talking about what it takes to be a good development manager. There are also articles about what makes a good developer. I thought it would be a good idea to describe what a developer needs from their manager.

Silverlight 2 Beta2 Released

Sat, 07 Jun 2008 06:31:02 GMT

Silverlight 2 Beta2 was released today. Silverlight 2 Beta2 supports a go-live license that allows you to start using and deploying Silverlight 2 for commercial applications. There will be some API changes between Beta2 and the final release, so you should expect that applications you write with Beta2 will need to make some updates when the final release comes out. But we think that these changes will be straight-forward and relatively easy, and that you can begin planning and starting commercial projects now.

What's Changed in Silverlight 2 Beta 2?

Sat, 07 Jun 2008 07:16:02 GMT

A good summary of what's changed in Beta 2.

Building a better web forms: Labels in form layouts

Fri, 06 Jun 2008 10:04:10 GMT

The project that I'm currently working on is really challenging. Together with my team, I am refactoring the presentation layer of some complex web application which user interface caused very bad user experience. One of the things we are working on is a form layout refactoring. In this article I'll show you how we tried to improve common form layouts by using underlined labels.

DZone PlugIn for Windows Live Writer

Thu, 05 Jun 2008 23:01:13 GMT

John Papa has written an excellent new plugin for Windows Live Writer that makes it super-easy to include a DZone widget in every posting you write! Want more traffic? Use this in combination with his dotNetKicks plugin, and watch your numbers climb!

Code based ASP.NET MVC GridView

Wed, 04 Jun 2008 12:31:05 GMT

Maarten Balliauw shows you how to build an ASP.NET MVC html helper extension method which generates a nice gridview-like control using pure code and MVC framework.