MVVMLight | A toolkit help to build Android MVVM Application | Model View Controller library

MVVM pattern is just a desired pattern to separate visual design from applicaton data structure, so when you say "MVVM pattern doesn't allow to put event handler (for mouse interaction) in view code-behind" maybe that is being too drastic. Try to stick to it for better designs but don't get too crazy at the beginning. Have a look at this page, it might be of interest.

WPF creates automatically the event handlers for you in the code behind, so that is the place for them. What you may want to do is to, instead of modifying your data directly inside your event handler, there will be a ViewModel whose methods will help you modify your data.

You can use the PreviewMouse(Up,Down,Move) events associated to the Canvas. It might be easier than trying to click on your shape, specially when several shapes may overlap. Obviously, if you have many shapes, there must be a way to know which shapes is going to be edited (manual selection through combobox, finding the closes shape to mouse click, etc)

From your design, one aspect that may give you some trouble is the fact that your viewModel manages 1 shape. It isn't wrong, but you need another VM layer that manages a collection of shapes. It can be done as another class or as a bunch of static methods in your MyRectViewModel:

Thanks to @Gert Arnold's suggestion of disabling proxy creation, I was able to pinpoint that as the smoking gun which fixed the problem.

Working with proxies - EF 6 Microsoft Docs

I found that with proxy creation disabled, it was not necessary to override the SaveChanges() method with the Transaction wrapper. That should match the default EF behavior anyway.

For completeness and for those finding themselves here in the future:

You can disable proxy creation in the initializer of your DbContext class as such:

Create a global variable in App.cs , initialize it in constructor.

Return the value from a public method and access it in iOS project .

Your original CommandParameter binding does not work because a ContextMenu is not part of the same visual tree as the control it is associated with and the ancestor type is wrong (ListBox instead of ListView). The original binding below translates to find the first parent of type ListBox, get its SelectedItem and assign it as CommandParameter.

The EventToCommand action from MvvmLight is based on the legacy Blend SDK assemblies.

• XML namespace http://schemas.microsoft.com/expression/2010/interactivity
• CLR namespace System.Windows.Interactivity

These are in fact deprecated and replaced by the open source XAML behaviors that you use. The issue is that these assemblies are incompatible, so you cannot use the actions provided by MvvmLight with the XAML behaviors and vice-versa. I guess MvvmLight will be updated to use these behaviors in the future, too. Here is an open issue on this topic.

However, you do not need EventToCommand, as the XAML behaviors package already contains a command that does the same: InvokeCommandAction. The property names might be different, though.

As Clemens said, we should use => DataProvider.TodayDayCourse2.ToList() instead of => DataProvider.TodayDayCourse2. Because the latter always returns the same instance, while is not a property changed.

Since the CheckBox is within a DataTemplate, it gets the data context of its parent - The ItemSource of the ListView in this case - unless specifically overridden. You can adjust the source context for the binding by adding a DataContext attribute to the checkbox as in:

Prism 7.2.0.1422 brings it's own (old) version of the XAML Behaviors and you are mixing the new nuget package and the old version, that might be the issue. have you tried using

Is there a method that I can do this in XAML? Something with Binding?

Just bind the Text property of the TextBox to a string source property of the view model and raise call the RaiseCanExecuteChanged method of the command from the setter of this one.

If you really want to handle an actual event for some reason, you should look into interaction triggers.