Mvvm mouse events

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Mvvm mouse events

I have to open a new window on image mouse hover and close it on mouse leave. The events are firing one after the other. The new windows are opening and closing even when the mouse is at stand still on the image. I am following MVVM pattern and i am using interactivity dll for converting to fire commands on mouse hover events.

Do you mean that the MouseLeave fire when the mouse pointer is still over the Image? Does this happen even if you remove the margins?

You could try to put the Image inside a Grid with a Background and handle the Grid's events:.

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Event Aggregation in WPF - A TimCo Retail Manager Video

Ask a question. Quick access. Search related threads. Remove From My Forums. Answered by:. Archived Forums. Sign in to vote. Hi All, I am facing a problem in implementing mouse hover functionality on an image. Can any one help me out.

Thanks in advance. Wednesday, September 17, AM. Marked as answer by somsekhark Wednesday, September 17, PM. Thanks a lot it worked. Wednesday, September 17, PM.Ideally, the code-behind of a view — typically a Window or a UserControl — contains only a constructor that calls the InitializeComponent method and perhaps some additional code to control or interact with the view layer that is difficult or inefficient to express in XAML, e. Instead, in addition to providing properties to expose data to be displayed or edited in the view, the view model defines actions that can be performed by the user and typically expose these as commands.

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A command is an object that implements the System. ICommand interface and encapsulates the code for the action to be performed. It can be data bound to a UI control in the view to be invoked as a result of a mouse click, key press or any other input event.

As well as the command being invoked as the user interacts with the UI, a UI control can be automatically enabled or disabled based on the command. The Execute method of the ICommand interface encapsulates the operation itself while the CanExecute method indicates whether the command can be invoked at a particular time or not.

Handling mouse events in WPF / MVVM using MvvmLight Event Triggers

The interface also defines a CanExecuteChanged event that is raised on the UI thread to cause every invoking control to requery to check if the command can execute. RoutedCommand and System.

RoutedUICommand where the latter is a subclass of the former that simply adds a Text property that describes the command. However, neither of these implementations are especially suited to be used in a view model as they search the visual tree from the focused element and up for an element that has a matching System.

CommandBinding object in its CommandBindings collection and then executes the Execute delegate for this particular CommandBinding. Instead, you can create your own command by creating a class that implements the ICommand. The below implementation is a common one that invokes delegates for the Execute and CanExecute methods. DelegateCommand class available. The view model will then expose properties of this type for the view to bind to.

Also note that when the value of the string property changes, a RaiseCanExecuteChanged method is called to raise the CanExecuteChanged event in order to update the status of any control in the view that is bound to the command.

With this approach you have now moved the presentation logic from the view to the view model. There is an alternative way of associating a control in the view with a command object exposed by the view model. Only some controls can actually bind to a command through the Command property, notably those derived from System.

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ButtonBase or System. If you want to attach a command to some other control or when you want to invoke a command on an event other than the click event for a button, you can use Expression Blend interaction triggers and the System.

InvokeCommandAction class. Below is an example on how you would execute a command object called MouseEnterCommand in the view model when the user moves the mouse pointer over a Rectangle element in the view. You specify the event for which the command will be executed in the EventName property of the EventTrigger.

Remember to add a reference to System. If you wish to pass a parameter to a command from the view you do so by using the CommandParameter property. Besides the InvokeCommandAction class, there is also another class named CallMethodAction that can be used to invoke a method in the view model from the view without using commands.

It has a MethodName property for specifying the name of the method to call and a TargetObject property that needs to be bound to an instance of the class containing the method, i. Note that the CallMethodAction class is defined in another assembly and namespace and you will need to add a reference to Microsoft.

It is not full collection of handling events in MVVM.Select System. Interactivity reference:. So that when we run the empty WPF application and left click anywhere on the window, the event gets handled, as evidenced by the message box that gets invoked:.

Thanks — very useful. But how do you do this in a DataGridTextColumn when you want to edit in place and then have something happen after the edit? I have a file searching WPF app where the results appear in a DataGrid and the user can edit the filename column to rename a file — I need to catch the TextChanged event and do the File.

Move rename function in the ViewModel. A few of this replies in this blog post could be of help. He shows an example of having a TextBox within a datagridtemplatecolumn and putting the command inside there.

It can all get a bit tricky but works a treat once figured out… A future blog post with an example for THIS site perhaps? I think I am missing something. Why would you use this approach instead of simply using Input bindings in System.

You can. This site uses Akismet to reduce spam. Learn how your comment data is processed. Interactivity reference: And add this reference to the MainWindow. Interactivity" So that the MainWindow. Windows; using System. Show "Responding to left mouse button click event Related Posts.

About The Author Andy. Latest Comments. Mike 15 July Andy 15 July Joe O'Leary 19 December Andy 19 December Neil 4 February Andy 4 February You can create them in any folder you like.

mvvm mouse events

Leave a Reply Cancel reply Comment.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. Code Review Stack Exchange is a question and answer site for peer programmer code reviews. It only takes a minute to sign up. If so is the code I use right now bad?

I'm not sure if there is a better way but I somehow have to get the information where the user clicked and recieve the DataContext if it is an rectangle. I'm not sure where this whole thing with lazy initialization is coming from it is not the first time I see itbut it makes no sense to me.

What's the point in lazy initialization for commands? Just use regular readonly property:. And initialize it in constructor.

It is cleaner and requires less code to write. Also you might want to create another constructor for your command, that passes null for CanExecute by default. Sign up to join this community. The best answers are voted up and rise to the top. Home Questions Tags Users Unanswered.

Asked 2 years, 9 months ago. Active 2 years, 9 months ago. Viewed 4k times. Problems I see already: Somehow need to check that the recieved original source is actually a rectangle and not the canvas. Active Oldest Votes. You do leak views to your viewmodel though. Some better approaches: Handle event on rectangle itself. It will allow you to bind it's DataContext directly to command parameter. This should eliminate the leak. Use items control that supports selection, i. Then you will be able to bind to SelectedItem property directly without any events.

Other minor things: Base postfix is normally used to indicate an abstract class. Might want to remove it from your command class, since it is clearly not abstract.

Nikita B Nikita B I will try to correct my code. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name. Email Required, but never shown.The CellUnloaded and RowUnloaded events can in turn be used to remove those handlers in order to avoid memory leaks. You should not directly set properties of the visual elements GridViewCellGridViewRow as this will result in inconsistent behavior due to the control's UI Virtualization mechanism.

Instead, you should use the underlying data items as explained in the Style Selectors section. The sender argument contains the RadGridView. This argument is of type objectbut can be cast to the RadGridView type. A CellEventArgs object.

mvvm mouse events

This object exposes a Cell property - the loaded cell. This object exposes a Cell property - the unloaded cell. A common scenario in which the CellUnloaded can be used is to remove the handler s added in the CellLoaded event. A common scenario in which the RowUnloaded can be used is to remove the handler s added in the RowLoaded event. All Rights Reserved. See Trademarks for appropriate markings.

UI for WPF. API Reference. AddHandler GridViewCell. Show "Left-clicked header cell! Show "Left-clicked cell!

MVVM event to command binding #2: Behaviors and event triggers

AddHandler GridViewRow. DataContext as Club; MessageBox. DataContext, Club MessageBox. RemoveHandler GridViewRow. In this article. Not finding the help you need? Contact support. Was this article helpful? Tell us how we can improve this article. Submit Skip.One of the biggest points of friction for me when implementing the MVVM pattern happens when I need to bind commands to events. When using PrismI get the Button. Click command binding out of the box, but every other event needs to be wired up individually.

Doing this requires a LOT of boilerplate code that is very easy to get wrong. In my last post, I published some code to alleviate that pain. Still, it requires you to write a new behavior and attachment for every event that you want to bind an event to.

For a while now, I have toyed with the idea of just binding commands to events directly. I ran into a lot of bumps in the road. For instance, every event handler has a different event argument type. This requires all of the handlers to be dynamic.

Creating arrays of structures created its own troubles — binding only works with FrameworkElements within the visual tree. This required me to write my own crude binding within my generic behavior. I tested this code in Silverlight and WPF and it works really well! I no longer need to write any extra code whenever I want to attach commands to my events! There are a few caveats to this code:. Welcome to Geeks with Blogs. Brian Genisio. Post Categories Site. I thoroughly recommend that you investigate Caliburn.

You may also find the section on IResult interesting. Left by Rob on Aug 29, AM. Is there and advantages to this method over prism's event aggragator? The more I lean about EA; the more I start to think that's the only way I'll ever do events in silverlight. Eric: I am quite fond of the Event Aggregator as well I use it and find it extremely useful.

Is there a way to bind events in XAML? I use it to communicate from ViewModel to ViewModel, but when I want to execute a command in the ViewModel that is bound to the View, I find this mechanism really useful. Mostly because I don't want to broadcast that a button was clicked in the EA.

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I want the mouse click event to bind to a command in my ViewModel, and let the ViewModel decide what it means to have the command be executed. If the ViewModel wants to send an event to other components using the EA, then it can do so. Do you use the EventAggregator differently?

Rob: My biggest problem with Caliburn is my Lawyers. I work for a big company and open source software is a bear to get past them. You should have seen the hoops I needed to jump through to use SQLite. I got them to be OK with Prism because it was put out by Microsoft.

mvvm mouse events

I don't like this limitation, but it "is what it is". Because of this, I blog from the perspective Although, it is starting to get tiresome to be doing this much plumbing. That being said, I have spent some time looking into Caliburn, I've got to say that it looks nice. It has been my plan for several months to dig into Caliburn and really get to know it.Create custom interactions only if there is a clear, well-defined requirement and the interactions supported by the platform controls don't support your scenario.

If you customize the interaction experiences in your Windows application, users expect them to be consistent, intuitive, and discoverable. For these reasons, we recommend that you model your custom interactions on those supported by the platform controls. The platform controls provide the full Universal Windows Platform UWP user interaction experience, including standard interactions, animated physics effects, visual feedback, and accessibility.

Because the raw Human Interface Device HID data provided by these input devices includes many common properties, the data is promoted and consolidated into a unified input stack and exposed as device-agnostic pointer data. Your UWP applications can then consume this data without worrying about the input device being used. Each input point or contact on the input stack is represented by a Pointer object exposed through the PointerRoutedEventArgs parameter in the various pointer event handlers.

In the case of multi-pen or multi-touch input, each contact is treated as a unique input pointer. Pointer events expose basic info such as input device type and detection state in range or in contactand extended info such as location, pressure, and contact geometry. In addition, specific device properties such as which mouse button a user pressed or whether the pen eraser tip is being used are also available.

If your app needs to differentiate between input devices and their capabilities, see Identify input devices. Constrain pointer input to a specific UI element by calling CapturePointer on that element within a pointer event handler.

When a pointer is captured by an element, only that object receives pointer input events, even when the pointer moves outside the bounding area of the object. The IsInContact mouse button pressed, touch or stylus in contact must be true for CapturePointer to be successful.

Occurs when a pointer is canceled by the platform. This can occur in the following circumstances:.

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Occurs when another UI element captures the pointer, the pointer was released, or another pointer was programmatically captured. Occurs when a pointer enters the bounding area of an element. This can happen in slightly different ways for touch, touchpad, mouse, and pen input. Occurs when a pointer leaves the bounding area of an element. Occurs when a pointer changes coordinates, button state, pressure, tilt, or contact geometry for example, width and height within the bounding area of an element.

Occurs when the pointer indicates a press action such as a touch down, mouse button down, pen down, or touchpad button down within the bounding area of an element. CapturePointer must be called from the handler for this event.

Occurs when the pointer indicates a release action such as a touch up, mouse button up, pen up, or touchpad button up within the bounding area of an element or, if the pointer is captured, outside the bounding area.


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