As with Silverlight, there is no mention of theWindows Presentation Foundation (WPF) in my book, “Professional IronPython.” The WPF is supposed to help solve some display problems for application developers and allow better use of modern graphics processors. Microsoft has provided a significant amount of information about the WPF that I won’t be discussing in this post. Whether you find WPF helpful or not depends on the kind of applications you create. I’m sure that WPF will find use in game applications, widgets of various sorts, mini-applications, and a host of other uses, but I’m not sure just what it adds to the common business application, such as a data entry application. Still, WPF is an exciting new technology that you should investigate.
As with the Silverlight project in my previous post, you need to have the PTVS installed on your system to work through this example. To begin this example,
you start Visual Studio as normal and choose File | New to create a new
project. The New Project dialog box should contain an entry for a Wpf Application template as shown here. If you don’t see
this template, then you probably don’t have IronPython 2.7 installed on
your system and can use the instructions found in the IronPython 2.7 and PTVS blog entry to install it.
The example will accept the default name for the project. Of course, you can use any name that you’d like. Click OK. You’ll see a new WPF application. However, for some odd reason, the eXtensible Application Markup Language (XAML) (pronounced zammel) file doesn’t always open, so you’ll have to open it manually. At this point, you’ll see a project similar to the one shown here.
The top half of the designer shows what the page will look like, while the bottom half shows the associated XML. As you add controls to the form and configure them, you’ll see the changes in the XML, making it easy to code changes to the controls when necessary. Of course, you can choose to display just the Design window or just the XAML window if desired. Depending on the amount of screen real estate at your disposal, collapsing one of the panes by clicking Collapse Pane at the right side of the window, may be a good idea.
One of the advantages of using WPF is that you have immediate access to the Ribbon without having to employ any odd programming techniques. You just drag and drop the Ribbon controls from the Toolbox as you would any other control. Here’s a subset of the default set of WPF controls you can access from IronPython.
The example isn’t going to do anything fancy. I’ve added two Button controls to the form. Here is how I set the various properties using XAML:
The first button displays a simple message box, while the second ends the application. Each Button control is assigned basic visual properties, a name, and an event handler for its Click() event. One thing I dislike about working with WPF is that the Properties window doesn’t display any quick help for the various properties. You need to know what each property does or look it up, which is really inconvenient.
The code behind for this example relatively simple. As previously mentioned, the first control displays a message, while the second closes the application as shown here:
Much of this code is automatically generated for you. In order to use the MessageBox class, you must add it to the import statement as shown in the code. The code begins with the initialization, which simply loads the components from WpfApplication1.xaml.
The btnCancel_Click() event handler relies on the MyWindow object’s Close() method. Make sure you pass a copy of self as part of the call.
The btnMessage_Click() event handler makes a call to the MessageBox.Show() method with a simple text message. You’ll see the dialog box appear as expected.
From what I can see, the WPF support for IronPython in PTVS is on par with WPF support for any other .NET language. It has the same limitations and benefits as any WPF application will have. So, what do you think of the new WPF project support provided by PTVS? Let me know at John@JohnMuellerBooks.com.