I have usercontrol in which I have a listbox and in my mainwindow.xaml I am using two usercontrols and trying to clear selectedItem of one listbox of usercontrol1 if usercontrol2 listbox item is selected and vice versa using interaction Trigger and viceversa.
<i:Interaction.Triggers>
<i:EventTrigger EventName="SelectionChanged">
<ei:ChangePropertyAction PropertyName="SelectedItem" Value="{x:Null}" TargetObject="{Binding ElementName=usercontrol1}"/>
</i:EventTrigger>
</i:Interaction.Triggers>
When I try this in sample example directly having two controls it is working but with usercontrol selection not clearing.
Can someone guide me how to achieve this?
Thanks in advance.
Regards,
Nagasree.
Related
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 MVVMLight EventToCommand can be used to fire an ICommand on your viewmodel quite easily.
<DataGrid>
<i:Interaction.Triggers>
<i:EventTrigger EventName="SelectionChanged">
<GalaSoft_MvvmLight_Command:EventToCommand
Command="{Binding ProductSelectionChangedCommand, Mode=OneWay} "
CommandParameter="{Binding SelectedItems, ElementName=gridProducts}" />
</i:EventTrigger>
</i:Interaction.Triggers>
</DataGrid>
In this instance the SelectionChanged event belongs to DataGrid, and the Interaction.Triggers xaml is nested directly inside DataGrid.
I cannot figure out how to do the same when the event is a DataGridRow (which has its own events for each row).
I managed to do this, but it involves a handler function which I'd like to avoid :
<DataGrid>
<DataGrid.ItemContainerStyle>
<Style TargetType="DataGridRow">
<EventSetter Event="DataGridRow.MouseEnter"
Handler="Row_MouseEnter"/>
</Style>
</DataGrid.ItemContainerStyle>
</DataGrid>
In the Row_MouseEnter event (on my .xaml.cs file) I just 'find the command' on the ViewModel and trigger it programatically.
I'd really like to know if there's a way of doing the same directly with Interaction.Triggers
(FYI: What I'm doing is I have a panel above the grid which displays details of the row that the mouse is over before clicking on it - which triggers a detail view).
Yeah you can directly bind to the command in your ViewModel by creating your own custom behaviour class and using it in xaml file. These links might get you started - Binding using interactivity and Binding through interaction in MVVM
I have a slider control in view i need to call the ValueChanged event of slider and update one property in model based on that. how i can implement this using MVVM pattern.
where I have to write the ValueChanged event? how i can connect ValueChanged event code with view?
i just take the answer from here cause i use it in my projects too:
You should use an EventTrigger in combination with InvokeCommandAction from the Windows.Interactivity namespace. Here is an example:
xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
<i:Interaction.Triggers>
<i:EventTrigger EventName="SelectionChanged">
<i:InvokeCommandAction Command="{Binding SelectedItemChangedCommand}"/>
</i:EventTrigger>
</i:Interaction.Triggers>
I have a WPF 3.5 app built using MVVM pattern. I have a tabcontrol and I want to excecute an ICommand on the view model when the user clicks a certain tab (jn my case the "Preview" tab).
How do I hook up my ICommand to the tabitem or tabcontrol using just the XAML? I am using MVVM so I dont want to use events and get filthy, dirty code in the code-behind.
I think Im missing something simple here!
Thanks,P
Please refer this article : hooking up commands to events
Or you can use this approach
You should use InvokeCommandAction, Looks like this:
<TabItem Header="TabItem">
<i:Interaction.Triggers>
<i:EventTrigger EventName="MouseLeftButtonDown">
<i:InvokeCommandAction Command="SomeCommand"/>
</i:EventTrigger>
</i:Interaction.Triggers>
<Grid />
</TabItem>
Be sure to include the xmlns in the top:
xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
and of course to reference System.Windows.Interactivity (new in WPF4)
I want to use hyperlink in wpf xaml. Whenever mouse comes over the hyperlink, it should show image related to that hyperlink and when mouse gets away the image should disappear. How to go about this using bindings. I am using mvvm light.
Kindly Suggest.
Thanks
The basic framework of what you will need, if you want to accomplish this in an MVVM style is...
You will need to start by setting up a Behavior to Command the Hyperlinks MouseEnter MouseLeave events.
<Hyperlink NavigateUri="Uri">
<i:Interaction.Triggers>
<i:EventTrigger EventName="MouseEnter">
<Command:EventToCommand Command="HoverCommand" PassEventArgs="True" />
</i:EventTrigger>
<i:Interaction.Triggers>
<i:Interaction.Triggers>
<i:EventTrigger EventName="MouseLeave">
<Command:EventToCommand Command="HoverCommand" PassEventArgs="True" />
</i:EventTrigger>
<i:Interaction.Triggers>
Link text.
</Hyperlink>
Now setup a control that will hover when the its DataContext is not null
Use the command to set the controls DataContext on hover to the Uri of the image, on Leave set the datacontext to null.