How to convert the Checkbox.checked routed event to the command for MVVM pattern?
Reference-Consider the button click routed event, When we assign the command for button then button.click event is considered as command. It executes respective that command.
I googled for it, i got the solution with EventBehaviourFactory. Is it possible without using the EventBehaiourFactory?
It is a common requirement in WPF. The most widely used solution is using Interactivity from the Blend SDK:
Add this xmlns namespace to your xaml:
xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
Then you can do:
<CheckBox>
<i:Interaction.Triggers>
<i:EventTrigger EventName="Checked">
<i:InvokeCommandAction Command="{Binding MyCommand}" />
</i:EventTrigger>
</i:Interaction.Triggers>
</CheckBox>
Of course, you need to add System.Windows.Interactivity.dll to your project, located (for me at least) at: C:\Program Files (x86)\Microsoft SDKs\Expression\Blend 3\Interactivity\Libraries\WPF\System.Windows.Interactivity.dll
Related
I have installed MVVMLIGHT but still somehow I can't access EventToCommand property even after adding the reference files and using the namespaces in xaml file
xmlns:i="http://schemas.microsoft.com expression/2010/interactivity"
xmlns:cmd="clr-namespace:GalaSoft.MvvmLight;assembly=GalaSoft.MvvmLight"
<Textbox x:name="quantity">
<i:Interaction.Triggers>
<i:EventTrigger EventName="TextChanged">
//not working <cmd:EventToCommand Command="{Binding quantityCommand}"/>
</i:EventTrigger>
</i:Interaction.Triggers>
</Textbox>
Even InvokeCommandAction would work but I m not getting that too.Plz show me.thank you in advance
I am learning WPF using the MVVM pattern. I am trying to use the InvokeCommandAction behavior on a button. In Blend, I placed a button on my view. I then dragged the InvokeCommandAction onto the button.
Blend displays the Properties tab. The trigger is set to "Click". I set Command to CloseCommand : (IComamnd) in my view using the "Create Data Binding" dialog.
This generates the following XAML
<Button x:Name="CloseApp" Content="Close" >
<i:Interaction.Triggers>
<i:EventTrigger EventName="Click">
<i:InvokeCommandAction Command="{Binding CloseCommand}"/>
</i:EventTrigger>
</i:Interaction.Triggers>
</Button>
CloseCommand is a RelayCommand : ICommand from MSDN. The project compiles, but when I click on the button, the command does not execute. Any ideas, or sample code to point me to.
I am using Visual Studio 2010 SP1. I've met a lot of articles where describes code of event handling(see below). For example this and this one.
I've added an assembly System.Windows.Interactivity. I am using ICommand interface to handle Commands. However, when I write a property "Command" in the line:
<i:InvokeCommandAction Command="{Binding SelectionChangedCommand}"/>
I catch an error: Property "Command" does not exist in namespace XML "clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"..
<ListBox ItemsSource="{Binding SomeData}" Grid.Row="2" Margin="10" Background="LightGreen">
<i:Interaction.Triggers>
<i:EventTrigger EventName="MouseEnter">
<i:InvokeCommandAction CommandName="{Binding SelectionChangedCommand}" CommandParameter="{Binding YourCommandParameter}"/>
</i:EventTrigger>
</i:Interaction.Triggers>
</ListBox>
Thus I have two questions:
Where can I get a property Command? Or what should I write instead of it? I've tried to write CommandName but I've caught an error.
What should I write to CommandParameter property? What type of a property should I create in a viewmodel to bind it to CommandParameter?
As we talked in the WPF chat room, take a look in the following question, it is quite similar to your problem.
Properties does not exist : System.Windows.Interactivity?
How can I let my controls on the window know that their states should be changed. I have to use ICommand and since controls can have different states (Enable/Disable , Checked/Unchecked ...) have to handle them with VisualStateManager.
This could be a possible scenario:
When Record button is clicked(Checked) the other controls in the window should be uncheckable and once the recording is finished they should be checkable and many other scenarios.
Any help would be really appreciated.
Thanks.
You can achieve it with the help of interaction and interactivity. See if it helps.
Add below references in your XAML
xmlns:ei="http://schemas.microsoft.com/expression/2010/interactions"
xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
You can bind your ICommand and provide a VisualState name that will be applied when Button is clicked
<Button>
<i:Interaction.Triggers>
<i:EventTrigger EventName="Click">
<i:InvokeCommandAction Command="{Binding YourICommand}" />
<ei:GoToStateAction StateName="YourVisualStateName" />
</i:EventTrigger>
</i:Interaction.Triggers>
</Button>
If you don't have Blend 4, you can install the Blend 4 SDK to get the current behavior assemblies.
The WPF ListView class can be set up to automatically handle scrolling without an external ScrollViewer and it's possible to register an event handler for the control's internal scrollbar by writing XAML like such:
<ListView ScrollViewer.ScrollChanged="ScrollChanged" />
How to attach it to MVVM light Command? I tried the following, but it doesn't work:
<ListView>
<i:Interaction.Triggers>
<i:EventTrigger EventName="ScrollViewer.ScrollChangedEvent">
<cmd:EventToCommand Command="{Binding ScrollCommand}" />
</i:EventTrigger>
</i:Interaction.Triggers>
</ListView>
Note: ScrollCommand - is a RelayCommand from my viewmodel.
EventTrigger doesn't trigger for routed events. You can use the solution proposed in this article
to create a RoutedEventTrigger class and use it instead of EventTrigger.
I recommend a Behavior for this. If you don't have Blend, you'll need to get the Blend SDK. But once you have that, you can follow this tutorial to extend the behavior of the ScrollViewer.