How to pass pressed key as command parameter in interraction?
<i:Interaction.Triggers>
<i:EventTrigger EventName="PreviewKeyDown">
<i:InvokeCommandAction Command="{Binding SomeCommand}" CommandParameter="???PressedKey???"/>
</i:EventTrigger>
</i:Interaction.Triggers>
EventTrigger doesnt expose details about the event, it just registers to it.
https://msdn.microsoft.com/en-us/library/system.windows.eventtrigger(v=vs.100).aspx
You could instead write a Behavior, there you will control over which key etc:
https://wpftutorial.net/Behaviors.html
this code may solve your issue (It is for search with keypress by Binding) :
<TextBox Height="20" Margin="-30,2,0,0" Name="searchText" Text="{Binding SearchText}" Width="254" >
<i:Interaction.Triggers>
<i:EventTrigger EventName="EditValueChanged">
<i:InvokeCommandAction Command="{Binding SearchFieldCommand}" CommandParameter="{Binding ElementName=searchText, Path=Text,UpdateSourceTrigger=PropertyChanged }" />
</i:EventTrigger>
</i:Interaction.Triggers>
</TextBox>
To better understand this code should be familiar with PropertyChanged
Related
I have a text box A with an interaction trigger. The Data Context of the text box is a property in the view model. However, the ClearCommand in defined in the view Model. How can I change the Data Context of the Interaction Triggers or its Command to the view model it self.
Thank you
<TextBox Name="TextBoxA"Text="{Binding myObject.TextPrp,UpdateSourceTrigger=PropertyChanged}">
<i:Interaction.Triggers>
<i:EventTrigger EventName="TextChanged">
<i:InvokeCommandAction Command="{Binding ClearCommand}"
CommandParameter="{Binding ElementName=TextBoxB,Path=Text}"></i:InvokeCommandAction>
</i:EventTrigger>
</i:Interaction.Triggers>
</TextBox>
You have to bind to relative source like this
<TextBox Name="TextBoxA"Text="{Binding myObject.TextPrp,UpdateSourceTrigger=PropertyChanged}">
<i:Interaction.Triggers>
<i:EventTrigger EventName="TextChanged">
<i:InvokeCommandAction Command="{Binding RelativeSource={RelativeSource AncestorType={x:Type YourUserControl}, Path=DataContext. ClearCommand}"
CommandParameter="{Binding ElementName=TextBoxB,Path=Text}"></i:InvokeCommandAction>
</i:EventTrigger>
</i:Interaction.Triggers>
</TextBox>
<TextBox x:Name="DescriptionTextBox"
Text="{Binding SelectedEntity.Description,
ValidatesOnExceptions=True}">
<i:Interaction.Triggers>
<i:EventTrigger EventName="LostFocus" SourceName="DescriptionTextBox">
<ei:CallMethodAction MethodName="RaiseCanExecuteChanged"
TargetObject="{Binding Command, ElementName=SaveButton}" />
</i:EventTrigger>
</i:Interaction.Triggers>
</TextBox>
<userControls:SaveCloseUserControl />
Inside this user control
<StackPanel HorizontalAlignment="Right" Orientation="Horizontal">
<Button Width="50"
Command="{Binding SaveCommand}"
Content="Save" />
<Button Width="50"
Command="{Binding CloseCommand}"
Content="Close" />
</StackPanel>
The problem here is that this TargetObject="{Binding Command, ElementName=SaveButton}" does not find SaveButton because its inside of userControls:SaveCloseUserControl
I looked online and I found a solution (from 2009) that required code behind, is there not an easy way of doing this stuff today?
Regards
Edit
Based on #huzle answer I did this in the code behind of the user control
public object CreateButton { get { return CreateChild; } }
and in xaml i added a name to the save button.
so the my final version looks like this
<TextBox x:Name="DescriptionTextBox"
Text="{Binding SelectedEntity.Description,
ValidatesOnExceptions=True}">
<i:Interaction.Triggers>
<i:EventTrigger EventName="LostFocus" SourceName="DescriptionTextBox">
<ei:CallMethodAction MethodName="RaiseCanExecuteChanged"
TargetObject="{Binding CreateButton.Command,ElementName=MySaveCloseUserControl}"/>
</i:EventTrigger>
</i:Interaction.Triggers>
</TextBox>
<userControls:SaveCloseUserControl x:Name="MySaveCloseUserControl"/>
Give your "SaveCloseUserControl" a public properties for the "SaveButton" named "InnerSaveButton" and bind with ElementName to your SaveCloseUserControl and use the Path for getting to the Command of your inner button.
<TextBox x:Name="DescriptionTextBox"
Text="{Binding SelectedEntity.Description,
ValidatesOnExceptions=True}">
<i:Interaction.Triggers>
<i:EventTrigger EventName="LostFocus" SourceName="DescriptionTextBox">
<ei:CallMethodAction MethodName="RaiseCanExecuteChanged"
TargetObject="{Binding InnerSaveButton.Command, ElementName=MySaveCloseUserControl}" />
</i:EventTrigger>
</i:Interaction.Triggers>
</TextBox>
<userControls:SaveCloseUserControl X:Name="MySaveCloseUserControl"/>
Is the RightMouseDownEvent expected to work with EventToCommand?
I can bind a Command with PreviewMouseRightUp and PreviewMouseRightDown, but MouseRightButtonDown does nothing. Am I using the wrong event name -- is it that simple?
In the xaml -- i have both events bound to the same handler -- only one works (Preview...Up). I comment out each in turn, but only the Preview works.
Thoughts? Thanks!
<i:Interaction.Triggers>
<i:EventTrigger EventName="SelectionChanged">
<cmd:EventToCommand Command="{Binding SetActivePaneCommand}" CommandParameter="{Binding PaneOne}" PassEventArgsToCommand="False" />
<cmd:EventToCommand Command="{Binding ListSelectionChangedCommand}" PassEventArgsToCommand="True" />
</i:EventTrigger>
<i:EventTrigger EventName="MouseRightButtonDown">
<cmd:EventToCommand Command="{Binding PreviewMouseRightButtonUpCommand}" PassEventArgsToCommand="True" />
</i:EventTrigger>
<i:EventTrigger EventName="PreviewMouseRightButtonUp">
<cmd:EventToCommand Command="{Binding PreviewMouseRightButtonUpCommand}" PassEventArgsToCommand="True" />
</i:EventTrigger>
</i:Interaction.Triggers>
Some controls handle the MouseRightButtonDown event and doesn't let it propagate (e.g. MenuItem). You can test this easily if you're calling a code behind method instead of using a trigger and see if you'll reach a breackpoint in that method.
In your xaml:
MouseRightButtonDown="UIElement_OnMouseRightButtonDown"
In your code behind:
private void UIElement_OnMouseRightButtonDown(object sender, MouseButtonEventArgs e)
{ }
I have an editable ComboBox.
<ComboBox IsEditable="True">
<i:Interaction.Triggers>
<i:EventTrigger EventName="SelectionChanged">
<cmd:EventToCommand Command="{Binding CritereChangedCommand, Mode=OneWay}"/>
</i:EventTrigger>
<i:EventTrigger EventName="TextBoxBase.TextChanged">
<cmd:EventToCommand Command="{Binding CritereChangedCommand, Mode=OneWay}"/>
</i:EventTrigger>
</i:Interaction.Triggers>
</ComboBox>
I use GalaSoft.MvvmLight.Command.EventToCommand to bind the SelectionChanged event.
I also would like to bind the TextChanged event, but it is a little bit tricky:
This event is only accessible by the ComboBox TextBoxBase property, and I can't find the proper way to bind this event.
You can see one of my unsuccessful attempt: SelectionChanged binding works fine, but TextChanged binding does not.
I also tried this syntax:
<ComboBox IsEditable="True">
<TextBoxBase>
<i:Interaction.Triggers>
<i:EventTrigger EventName="TextChanged">
<cmd:EventToCommand Command="{Binding CritereChangedCommand, Mode=OneWay}" />
</i:EventTrigger>
</i:Interaction.Triggers>
</TextBoxBase>
<i:Interaction.Triggers>
<i:EventTrigger EventName="SelectionChanged">
<cmd:EventToCommand Command="{Binding CritereChangedCommand, Mode=OneWay}" />
</i:EventTrigger>
</i:Interaction.Triggers>
</ComboBox>
But this won't even compile. I get an error "Type that can be instantiated expected" on the TextBoxBase tag.
Any idea ?
I know, very late response... but I hope it will help someone.
The problem here is that the EventTrigger class in Microsoft.Expression.Interactivity.dll uses reflection to find the event by the value of the EventName property and this won't work for attached events like TextBoxBase.TextChanged.
One option, which I use, is to implement your own custom EventTrigger class as described here and use this one instead of EventTrigger (the link there to CommandAction implementation is broken, but I managed to get it using internet archive).
Another option, which I don't like because it's not classic MVVM Command use, is to bind the Text property of the ComboBox to a property in the ViewModel and invoke the command from the ViewModel code on the setter, like this:
<ComboBox IsEditable="True"
Text="{Binding Text, Mode=TwoWay}" />
And in the ViewModel:
private string text;
public string Text
{
get { return text; }
set
{
text = value;
OnPropertyChanged("Text");
if(CritereChangedCommand.CanExecute())
CritereChangedCommand.Execute();//call your command here
}
}
I have found a way to work around the problem:
I create an invisible TextBox, bound to the ComboBox, and I bind the command on the TextChanged event of the TextBox.
It's not pretty, but it works...
<ComboBox Name="CbRubrique" IsEditable="True">
<i:Interaction.Triggers>
<i:EventTrigger EventName="SelectionChanged">
<cmd:EventToCommand Command="{Binding CritereChangedCommand, Mode=OneWay}" />
</i:EventTrigger>
</i:Interaction.Triggers>
</ComboBox>
<TextBox Text="{Binding ElementName=CbRubrique, Path=Text, UpdateSourceTrigger=PropertyChanged}" Visibility="Collapsed">
<i:Interaction.Triggers>
<i:EventTrigger EventName="TextChanged">
<cmd:EventToCommand Command="{Binding CritereChangedCommand, Mode=OneWay}" />
</i:EventTrigger>
</i:Interaction.Triggers>
</TextBox>
Using silverlight, we are looking to move the focus to a textbox.
How do you use mvvm-light to trigger gotfocus?
The view contains:
<TextBox Margin="4,4,0,0" Text="{Binding Path=SearchOID, Mode=TwoWay}">
<i:Interaction.Triggers>
<i:EventTrigger EventName="GotFocus">
<cmd:EventToCommand Command="{Binding GotFocusCommand, Mode=TwoWay}"/>
</i:EventTrigger>
</i:Interaction.Triggers>
</TextBox>
How should the ViewModel look?
How do you trigger this from the ViewModel?
Ended up using a TriggerAction, very similar to:
http://www.codeproject.com/Articles/42988/Silverlight-Behaviors-and-Triggers-Making-a-Trigge.aspx