Detecting 'MouseOver' events in WPF / MVVM
Useful StackOverflow link
https://stackoverflow.com/questions/36221118/how-to-make-mouseover-event-in-mvvm
Step 1: Create a new WPF project
Step 2: Create an example WPF window
MainWindow.xaml
[code language="xml"]
<Window x:Class="MouseOverEventMvvm.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:MouseOverEventMvvm"
xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
mc:Ignorable="d"
Title="MainWindow" Height="350" Width="525">
<Window.DataContext>
<local:MainWindowViewModel />
</Window.DataContext>
<Grid>
<Button Width="200" Height="100" Content="Navigate">
<i:Interaction.Triggers>
<i:EventTrigger EventName="MouseEnter">
<i:InvokeCommandAction Command="{Binding NavigateCommand}" CommandParameter="ViewImportProgress" />
</i:EventTrigger>
</i:Interaction.Triggers>
</Button>
</Grid>
</Window>
[/code]
Step 3: Create the MVVM View Model class
MainWindowViewModel.cs
[code language="csharp"]
using System.Windows;
using System.Windows.Input;
namespace MouseOverEventMvvm
{
public class MainWindowViewModel
{
private ICommand _navigateCommand;
public ICommand NavigateCommand
{
get
{
return _navigateCommand ?? (_navigateCommand = new RelayCommand(
x => { DoStuff(); }));
}
}
public void DoStuff()
{
MessageBox.Show("Mouse Over Button Event");
}
}
}
[/code]
Step 4: Add Event handling infrastructure
RelayCommand.cs
[code language="csharp"]
using System;
using System.Windows.Input;
namespace MouseOverEventMvvm
{
public class RelayCommand<T> : ICommand
{
private readonly Predicate<T> _canExecute;
private readonly Action<T> _execute;
public RelayCommand(Action<T> execute)
: this(execute, null)
{
_execute = execute;
}
public RelayCommand(Action<T> execute, Predicate<T> canExecute)
{
if (execute == null)
throw new ArgumentNullException(nameof(execute));
_execute = execute;
_canExecute = canExecute;
}
public bool CanExecute(object parameter)
{
return (_canExecute == null) || _canExecute((T) parameter);
}
public void Execute(object parameter)
{
_execute((T) parameter);
}
public event EventHandler CanExecuteChanged
{
add { CommandManager.RequerySuggested += value; }
remove { CommandManager.RequerySuggested -= value; }
}
}
public class RelayCommand : ICommand
{
private readonly Predicate<object> _canExecute;
private readonly Action<object> _execute;
public RelayCommand(Action<object> execute)
: this(execute, null)
{
_execute = execute;
}
public RelayCommand(Action<object> execute, Predicate<object> canExecute)
{
if (execute == null)
throw new ArgumentNullException(nameof(execute));
_execute = execute;
_canExecute = canExecute;
}
public bool CanExecute(object parameter)
{
return (_canExecute == null) || _canExecute(parameter);
}
public void Execute(object parameter)
{
_execute(parameter);
}
// Ensures WPF commanding infrastructure asks all RelayCommand objects whether their
// associated views should be enabled whenever a command is invoked
public event EventHandler CanExecuteChanged
{
add
{
CommandManager.RequerySuggested += value;
CanExecuteChangedInternal += value;
}
remove
{
CommandManager.RequerySuggested -= value;
CanExecuteChangedInternal -= value;
}
}
private event EventHandler CanExecuteChangedInternal;
public void RaiseCanExecuteChanged()
{
CanExecuteChangedInternal.Raise(this);
}
}
}
[/code]
EventRaiser.cs
[code language="csharp"]
using System;
namespace MouseOverEventMvvm
{
public static class EventRaiser
{
public static void Raise(this EventHandler handler, object sender)
{
handler?.Invoke(sender, EventArgs.Empty);
}
public static void Raise<T>(this EventHandler<EventArgs<T>> handler, object sender, T value)
{
handler?.Invoke(sender, new EventArgs<T>(value));
}
public static void Raise<T>(this EventHandler<T> handler, object sender, T value) where T : EventArgs
{
handler?.Invoke(sender, value);
}
public static void Raise<T>(this EventHandler<EventArgs<T>> handler, object sender, EventArgs<T> value)
{
handler?.Invoke(sender, value);
}
}
}
[/code]
EventArgs.cs
[code language="csharp"]
using System;
namespace MouseOverEventMvvm
{
public class EventArgs<T> : EventArgs
{
public EventArgs(T value)
{
Value = value;
}
public T Value { get; private set; }
}
}
[/code]
Step 5: Add necessary reference to Interactivity
Right click the References folder and select Add Reference...
Step 6: Try it.
Notice that as soon as the mouse cursor enters the Button control the event is fired and the dialog message is shown:
Step 2: Create an example WPF window
MainWindow.xaml
[code language="xml"]
<Window x:Class="MouseOverEventMvvm.MainWindow"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:local="clr-namespace:MouseOverEventMvvm"
xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
mc:Ignorable="d"
Title="MainWindow" Height="350" Width="525">
<Window.DataContext>
<local:MainWindowViewModel />
</Window.DataContext>
<Grid>
<Button Width="200" Height="100" Content="Navigate">
<i:Interaction.Triggers>
<i:EventTrigger EventName="MouseEnter">
<i:InvokeCommandAction Command="{Binding NavigateCommand}" CommandParameter="ViewImportProgress" />
</i:EventTrigger>
</i:Interaction.Triggers>
</Button>
</Grid>
</Window>
[/code]
Step 3: Create the MVVM View Model class
MainWindowViewModel.cs
[code language="csharp"]
using System.Windows;
using System.Windows.Input;
namespace MouseOverEventMvvm
{
public class MainWindowViewModel
{
private ICommand _navigateCommand;
public ICommand NavigateCommand
{
get
{
return _navigateCommand ?? (_navigateCommand = new RelayCommand(
x => { DoStuff(); }));
}
}
public void DoStuff()
{
MessageBox.Show("Mouse Over Button Event");
}
}
}
[/code]
Step 4: Add Event handling infrastructure
RelayCommand.cs
[code language="csharp"]
using System;
using System.Windows.Input;
namespace MouseOverEventMvvm
{
public class RelayCommand<T> : ICommand
{
private readonly Predicate<T> _canExecute;
private readonly Action<T> _execute;
public RelayCommand(Action<T> execute)
: this(execute, null)
{
_execute = execute;
}
public RelayCommand(Action<T> execute, Predicate<T> canExecute)
{
if (execute == null)
throw new ArgumentNullException(nameof(execute));
_execute = execute;
_canExecute = canExecute;
}
public bool CanExecute(object parameter)
{
return (_canExecute == null) || _canExecute((T) parameter);
}
public void Execute(object parameter)
{
_execute((T) parameter);
}
public event EventHandler CanExecuteChanged
{
add { CommandManager.RequerySuggested += value; }
remove { CommandManager.RequerySuggested -= value; }
}
}
public class RelayCommand : ICommand
{
private readonly Predicate<object> _canExecute;
private readonly Action<object> _execute;
public RelayCommand(Action<object> execute)
: this(execute, null)
{
_execute = execute;
}
public RelayCommand(Action<object> execute, Predicate<object> canExecute)
{
if (execute == null)
throw new ArgumentNullException(nameof(execute));
_execute = execute;
_canExecute = canExecute;
}
public bool CanExecute(object parameter)
{
return (_canExecute == null) || _canExecute(parameter);
}
public void Execute(object parameter)
{
_execute(parameter);
}
// Ensures WPF commanding infrastructure asks all RelayCommand objects whether their
// associated views should be enabled whenever a command is invoked
public event EventHandler CanExecuteChanged
{
add
{
CommandManager.RequerySuggested += value;
CanExecuteChangedInternal += value;
}
remove
{
CommandManager.RequerySuggested -= value;
CanExecuteChangedInternal -= value;
}
}
private event EventHandler CanExecuteChangedInternal;
public void RaiseCanExecuteChanged()
{
CanExecuteChangedInternal.Raise(this);
}
}
}
[/code]
EventRaiser.cs
[code language="csharp"]
using System;
namespace MouseOverEventMvvm
{
public static class EventRaiser
{
public static void Raise(this EventHandler handler, object sender)
{
handler?.Invoke(sender, EventArgs.Empty);
}
public static void Raise<T>(this EventHandler<EventArgs<T>> handler, object sender, T value)
{
handler?.Invoke(sender, new EventArgs<T>(value));
}
public static void Raise<T>(this EventHandler<T> handler, object sender, T value) where T : EventArgs
{
handler?.Invoke(sender, value);
}
public static void Raise<T>(this EventHandler<EventArgs<T>> handler, object sender, EventArgs<T> value)
{
handler?.Invoke(sender, value);
}
}
}
[/code]
EventArgs.cs
[code language="csharp"]
using System;
namespace MouseOverEventMvvm
{
public class EventArgs<T> : EventArgs
{
public EventArgs(T value)
{
Value = value;
}
public T Value { get; private set; }
}
}
[/code]
Step 5: Add necessary reference to Interactivity
Right click the References folder and select Add Reference...
Step 6: Try it.
Notice that as soon as the mouse cursor enters the Button control the event is fired and the dialog message is shown:
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