CODEWITHSUNDEEP
wpf
TalentTuner
TalentTuner

Reputation: 17556

Attach Behaviour Vs Routed Command

What is difference between the two, i am just confused so much on these two concepts and not able to apply correctly?

Upvotes: 2

Views: 1596

Answers (2)

Informagic
Informagic

Reputation: 1192

In search of a similar question, I came across Chapter 6 of the PRISM 5.0 Handbook, which states as a note on command-enabled controls versus behaviors:

WPF controls that support commands allow you to declaratively hook up a control to a command. These controls will invoke the specified command when the user interacts with the control in a specific way. For example, for a Button control, the command will be invoked when the user clicks the button. This event associated with the command is fixed and cannot be changed.

Behaviors also allow you to hook up a control to a command in a declarative fashion. However, behaviors can be associated with a range of events raised by the control, and they can be used to conditionally invoke an associated command object or a command method in the view model. In other words, behaviors can address many of the same scenarios as command-enabled controls, and they may provide a greater degree of flexibility and control.

You will need to choose when to use command-enabled controls and when to use behaviors, as well as which kind of behavior to use. If you prefer to use a single mechanism to associate controls in the view with functionality in the view model or for consistency, you might consider using behaviors, even for controls that inherently support commands.

If you only need to use command-enabled controls to invoke commands on the view model, and if you are happy with the default events to invoke the command, behaviors may not be required. Similarly, if your developers or UI designers will not be using Blend for Visual Studio 2013, you may favor command-enabled controls (or custom attached behaviors) because of the additional syntax required for Blend behaviors.

For me, this is the single best summary of what’s the difference between behaviors and commands.

Upvotes: 0

rudigrobler
rudigrobler

Reputation: 17133

Attached behaviors is a way of extending controls without having to subclass them! Examples of this is add watermarks to textboxes, forcing textboxes to only accept certain charecters, etc... It is typical stuff that you can do to a control by subscribing to certain events or setting properties! By creating a attached behavior, you are just encapsulating that functionalaty for reuse!

Routed Commands is a way of abstracting away your executing logic for actions like clicking on a button... in WPF, the build in implementation of ICommand, basically walks the visual tree looking for a RoutedCommand that it can execute! The real big diference between these too is that ICommand can only really work on things like buttons... If you need to execute some logic on clicking of a image, you can't without creating a attached behaviour!

Also read up on RelayCommand/DelegateCommand

UPDATE

Attaching a behavior to an object simply means making the object do something that it would not do on its own.

Josh Smith - http://www.codeproject.com/KB/WPF/AttachedBehaviors.aspx

Upvotes: 3

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