Alan Le's Vertigo Blog

Commands in WPF

I gave a short internal presentation @Vertigo last week about Commands in WPF. There's lot of information already on the web about this subject so I won't re-hash it here but instead link to the info instead.

Adam Nathan’s sample chapter on Important New Concepts in WPF: Commands

MSDN article: The Command Pattern In WPF

Keyvan Nayyeri: How to Add Commands to Custom WPF Control

Ian Griffiths: Avalon Input, Commands, and Handlers

Wikipedia: Command Pattern

MSDN Library: Commanding Overview

MSDN Library: CommandBinding Class

MSDN Library: Input and Commands How-to Topics

MSDN Library: EditingCommands Class

MSDN Library: MediaCommands Class

MSDN Library: ApplicationCommands Class

MSDN Library: NavigationCommands Class

MSDN Library: ComponentCommands Class

Also buried in the WPF SDK samples, there's a nice sample on RichTextBox editing which I've extended. You can find it here: RichTextEditor.zip

Posted by Alan Le | 4 Comments | Trackback Url | Bookmark with:

Tags:

Links to this Post

Comments

Thursday, 31 May 2007 04:08 by Re: Commands in WPF

<div class=ExternalClassC2F4B83112994F39AB38C7C5A3390D4E>Hi Alan, I've just looked at your sample. It is clear and easy how commands work in this sample but in a real life scenario the bold button for example should reflect if the current selected text is bold or not. The same applies to italic and the paragraph alignment. Is there any way of achieving this with commands? I wonder how useful Commands really are if there isn't a way of reporting back a custom state other than CanExecute. I've asked this question on the WPF Forum as well: http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=1670825&SiteID=1</div>

Thursday, 31 May 2007 04:39 by Re: Commands in WPF

<div class=ExternalClassCEDC49FDF7544DC7817458E7256CEA31><div>Hi Patrick, thanks for the comment. Interesting point about the button state based on selected text in the richtextbox. I don't think there is built-in mechanism with the Command Pattern to support that.</div> <div> </div> <div>I think there's a way though. As a proof of concept, i wrapped my bold button control inside of a checkbox control so i can set whether it's checked or not.</div> <div> </div> <div> <CheckBox x:Name="BoldButton"> <Button Style="{StaticResource formatTextStyle}" Command="EditingCommands.ToggleBold" ToolTip="Bold"> <TextBlock FontWeight="Bold">B</TextBlock> </Button> </CheckBox></div> <div>Then to set the IsChecked property I have a handler on the richTextBox's SelectionChanged event.</div> <div> </div> <div> void mainRTB_SelectionChanged(object sender, RoutedEventArgs e) { if (!mainRTB.Selection.GetPropertyValue(FontWeightProperty).Equals(DependencyProperty.UnsetValue)) BoldButton.IsChecked = ((FontWeight)(mainRTB.Selection.GetPropertyValue(FontWeightProperty))) == FontWeights.Bold ? true : false; } I think this might even be done with binding in xaml and a generic dependency property to bold converter.</div></div>

Sunday, 3 Jun 2007 06:38 by Re: Commands in WPF

<div class=ExternalClass36B3A856EBC5487BA1D8818726E201F1>Thanks for the response Alan. I thought about something like this at first too, but that would mean that we have to 'couple' the richtext box with the button thus eliminating one of the advantages of Commands. I wonder if there is a way of transporting this information via an extended Command and a custom implementations of the command bindings. At the moment I don't have enough knowledge about Commands to come up with a proof of concept but I am eager to find out :-). If you have any hints or further ideas I would appreciate that. Cheers, Patrick</div>

Monday, 2 Jul 2007 08:22 by Re: Commands in WPF

<div class=ExternalClassE3438B59BD2B480BA670FC5E78576A1B>Hi Alan, Finally I have come up with a simple work around for this kind of problem. I've described it here: http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=1809894&SiteID=1 cheers, Patrick</div>

Name:

URL:

Email:

Comments:

CAPTCHA Image Validation

Links

Photos
Archive
Archive (Calendar)

Alan Le's Vertigo Blog

Links to this Post

Comments

Archives

Categories

Links

Contact

Project inquiries

Employment opportunities

Vertigo