In this post I want to dig a little deeper into how I implemented my touch-item cmdlet. I decided to use VisualStudio 2010, since it's the most recent release of VS as of now. I think prior versions of VS will work just as well, and most of this discussion will still be relevant if you are using VS 2008, 2005, etc.
Step 1 - Prerequisites
When starting out, you will need (of course) a version of Visual Studio and PowerShell installed. PowerShell might already be installed, depending upon the version of Windows you're running. But if not, you will need to install it. I'm using PowerShell 2.0 for this example. To access the PowerShell types in System.Management.Automation, you need to add a reference to System.Management.Automation in your project file. There are multiple ways of doing this. I learned after the fact that you can just edit your .csproj file directly and add a line like this:
<Reference Include="System.Management.Automation" />
This is much easier than what I did. If I remember correctly, I installed the PowerShell SDK and then added the reference via the VS UI as you typically would. I had to browse for it, though. It didn't appear in the .NET tab in the Add Reference dialog. The path to the assembly is:
[program files]\Reference Assemblies\Microsoft\WindowsPowerShell\v1.0\System.Management.Automation.dll
Step 2 - Create the Class
When you create your Visual Studio project, you should create a class library. Once you have created your project and added the reference to System.Management.Automation, you can create a class file that will contain the code for your cmdlet. To avoid too much typing, I added a using System.Management.Automation statement to access the types without having to type the namespace every time.
Your class should inherit from one of the PowerShell cmdlet base classes - Cmdlet or PSCmdlet. The class must be public. And the class must be decorated with the Cmdlet attribute. The Cmdlet attribute specifies the verb-noun name of the cmdlet. The MS documentation states you should only use approved verbs. I broke that rule since "Touch" is not an approved verb (oh well). In all, your class declaration should appear as follows:
[Cmdlet("Set", "CoolnessLevel")]
class SetCoolnessLevelCommand : Cmdlet
{
... code goes here
}
You should now have a project that compiles. At this point, you are ready to start writing some actual code to do something interesting, which will be the topic of my next post.
If you can't wait until then, MSDN has some really good documentation on writing PowerShell cmdlets.
