EventToCommand Class

Executes a command in response to a raised event.

Assembly: DevExpress.WinUI.Core.v22.1.dll

Declaration

C#
VB.NET

public class EventToCommand :
    EventToCommandBase

Public Class EventToCommand
    Inherits EventToCommandBase

Remarks

Run Demo: Behaviors Module in the WinUI MVVM Demo

Specify an Event Owner

An event owner is an object that raises events. The default event owner object is a control associated with the EventToCommand behavior.

XAML

<UserControl ...
    xmlns:dx="using:DevExpress.WinUI.Core">
    <ListBox>
        <dx:Interaction.Behaviors>
            <dx:EventToCommand EventName="DoubleTapped" Command="{x:Bind ShowDetailCommand}"/>
        </dx:Interaction.Behaviors>
    </ListBox>
</UserControl>

You can use the EventOwner property to specify a different event owner object for the EventToCommand.

XAML

<UserControl ...
    xmlns:dx="using:DevExpress.WinUI.Core">
    <dx:Interaction.Behaviors>
        <dx:EventToCommand EventOwner="{x:Bind list}" EventName="DoubleTapped" Command="{x:Bind ShowDetailCommand}"/>
    </dx:Interaction.Behaviors>
    <!-- ... -->
        <ListBox x:Name="list" ... />
</UserControl>

Specify an Event

Use the EventName property to specify an event for the EventToCommand behavior:

XAML

<UserControl ...
    xmlns:dx="using:DevExpress.WinUI.Core">
    <dx:Interaction.Behaviors>
        <dx:EventToCommand EventName="Loaded" Command="{x:Bind LoadedCommand}" />
    </dx:Interaction.Behaviors>
    <!-- ... -->
</UserControl>

The default EventName property value is Loaded.

Pass a Parameter to the Bound Command

Use the CommandParameter property to pass a parameter to a command:

XAML

<ListBox x:Name="list">
    <dx:Interaction.Behaviors>
        <dx:EventToCommand EventName="DoubleTapped" Command="{x:Bind ShowDetailCommand}"
                           CommandParameter="{x:Bind list.SelectedItem, Mode=OneWay}"/>
    </dx:Interaction.Behaviors>
</ListBox>

Use one of the following properties to pass an event’s arguments to a command:

PassEventArgsToCommand

Specifies if the event’s arguments are passed to the command.

XAML

<ListBox x:Name="list" ...>
    <dx:Interaction.Behaviors>
        <dx:EventToCommand EventName="DoubleTapped" Command="{x:Bind ShowDetailCommand}" 
                           PassEventArgsToCommand="True"/>
    </dx:Interaction.Behaviors>
</ListBox>

EventArgsConverter

Allows you to maintain a clean MVVM pattern and convert the event’s arguments to an object suitable for the command.

XAML

<ListBox ...>
    <dx:Interaction.Behaviors>
        <dx:EventToCommand EventName="DoubleTapped" Command="{x:Bind EditCommand}">
            <dx:EventToCommand.EventArgsConverter>
                <local:CustomEventArgsConverter/>
            </dx:EventToCommand.EventArgsConverter>
        </dx:EventToCommand>
    </dx:Interaction.Behaviors>
</ListBox>

Specify Modifier Keys as an Additional Condition of the Command Execution

Use the ModifierKeys property to specify keys a user should press to invoke the command.

In the code sample below, the bound ShowDetailCommand is invoked when a user presses Alt and clicks or taps a ListBoxItem.

XAML

<ListBox ...>
    <dx:Interaction.Behaviors>
        <dx:EventToCommand EventName="Tapped" Command="{x:Bind ShowDetailCommand}" ModifierKeys="Alt">
            <dx:EventToCommand.EventArgsConverter>
                <local:ListBoxPointerEventArgsConverter/>
            </dx:EventToCommand.EventArgsConverter>
        </dx:EventToCommand>
    </dx:Interaction.Behaviors>
</ListBox>

Property	Description
AllowChangeEventOwnerIsEnabled	Gets or sets whether the event owner object’s IsEnabled property value reflects the command’s CanExecute method value. This is a dependency property.
DispatcherPriority	Gets or sets the priority of the DispatcherQueue that invokes the associated command. The default value is `null` which means that the DispatcherQueue is not used to invoke the associated command. This is a dependency property.
MarkRoutedEventsAsHandled	Gets or sets whether the associated routed event is marked as handled when the command is executed. This is a dependency property.
PassEventArgsToCommand	Gets or sets whether the event arguments are passed to the command. This is a dependency property.
ProcessEventsFromDisabledEventOwner	Gets or sets whether the EventToCommand processes events for event owner objects even if they are disabled. This is a dependency property.