Huddled Masses

Posts Tagged ‘Tutorial’

[new] Updated to PowerBoots 0.1

An introduction to PowerBoots

Please excuse me if I start by just copying the basic ideas of the Shoes Tutorial, but I figured that since PowerBoots is inspired by Shoes, that was as good a place as any to start. PowerBoots (or just “Boots”) is a PowerShell 2.0 module with functions for writing Windows Presentation Framework (WPF) applications in the PowerShell scripting language. You should get the latest version of PowerBoots before continuing, and install it by putting the “PowerBoots” folder in one of your “Modules” folders (list them by typing $Env:PSMODULEPATH in PowerShell v2).

Don’t forget to start PowerShell.exe with the STA parameter (This is no longer required in PowerBoots 0.1).

Did I hear someone ask what is WPF? It was introduced as part of .Net 3.0 (and vastly improved in .Net 3.5), so you can expect to find it preinstalled on computers from Vista on, and of course you can download and install it on XP if it’s not already installed. The only thing you really need to know about WPF for the purposes of this tutorial is that it is the new GUI toolkit for .Net, and that it is container based — you put elements into other elements to control the layout, rather like HTML and Java Swing… you can pick up the rest as we go along.

A simple Boots program

The parenthesis ( and ) are a container, so the button is “in” the Window. You can also pass a ScriptBlock instead, which works basically the same way. Of course, this is a bit uglier than the Shoes syntax, so lets see if we can’t clean it up some. The -Content parameter is positional, so the first non-named argument you pass will be used for that. The same is true for the -Children parameter of panels, and in fact, each of the other similar parameters: Items, Blocks, and Inlines.

We have used a function New-BootsWindow which has an alias Boots. Boots takes all the same parameters as the Window function mentioned previously, but it uses slightly more useful defaults, and has a few other major benefits as well, the first of which is that it automatically “shows” the window, and the second is that it supports an -Async parameter which allows the window to come out in a new thread so that you can continue using PowerShell while the window remains alive and responsive. There is one catch: New-BootsWindow cannot take it’s content on the pipeline (the old function, now renamed “Out-BootsWindow” can take pipeline content, but is a script function, and requires -STA mode) — you have to specify it as a ScriptBlock. So now that we know this, we can rewrite our first example like this:

Just for the record, the simplest Boots program would just be a simple popup dialog to put some text in a Window, like: Boots { $msg } …

We can put controls in a stack

StackPanels are awesome. So are WrapPanels. Try that code with a WrapPanel instead of a StackPanel and see what the difference is. This brings up another point: those positional parameters we mentioned earlier: Content, Children, Items, Blocks, and Inlines, are also set to accept the value from the pipeline. Not only that, but they are intelligent about whether or not the content model accepts multiple items! So we can actually rewrite that script like this, and get the same results:

Now we’re really onto something! Read the rest of this entry »

Someone asked on the PowerShell Newsgroup about writing Advanced Functions, and specifically:

looking for a … guide to putting together an advanced function that is visible and usable every time I start Powershell. By visible I mean that when I do a ‘get-command’ I want my [advanced function]s to be listed alongside all the regular cmdlets. What makes that possible? ... what do I need to do to make that happen? Whats the difference between an [advanced function] and a module?

There are lots of articles on the Microsoft PowerShell team blog about both topics, but it seems there’s not really been any sort of step-by-step written, so I posted this to the newsgroup, and since the person who asked the original question said he found it useful, I figured I’d share it here…