I have a DataGrid and need to handle its events. I have a business logic to be implemented which needs to be handled in the ViewModel and able to unit test.
Can I raise events and handle them in the ViewModel? In this case how to unit test?
You can use EventTrigger from System.Windows.Interactivity or MvvmLight
<DataGrid x:Name="myProtokollList">
<i:Interaction.Triggers>
<i:EventTrigger EventName="MouseDoubleClick">
<i:InvokeCommandAction Command="{Binding Path=OpenCommand}" CommandParameter="{Binding ElementName=myProtokollList, Path=SelectedItem.OriginalSatzX}"/>
</i:EventTrigger>
</i:Interaction.Triggers>
Related
In WPF MVVM application, I need same functionality for multiple controls - for example certain button does same thing as certain menu item. It is piece of cake with MVVM Light's RelayCommand, but I am now using Caliburn.Micro, where almost everything is based on conventions. So two controls can not have same x:Name="AddItem", which is used by CM to determine method for executing in ViewModel. Is there any simple way to solve this?
Yes, it's simple, but verbose. You need to use the "long format". Let's say you have one method IncrementCount on your ViewModel:
// Handling event
public void IncrementCount()
{
Count++;
}
And your View has:
<Button Name="ButtonOne">
<i:Interaction.Triggers>
<i:EventTrigger EventName="Click">
<cal:ActionMessage MethodName="IncrementCount" />
</i:EventTrigger>
</i:Interaction.Triggers>
</Button>
<Button Name="ButtonTwo">
<i:Interaction.Triggers>
<i:EventTrigger EventName="Click">
<cal:ActionMessage MethodName="IncrementCount" />
</i:EventTrigger>
</i:Interaction.Triggers>
</Button>
Both buttons will call your IncrementCount method.
EDIT
Add these namespaces
xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
xmlns:cal="http://www.caliburnproject.org"
You may see this Caliburn starting project using the snippets above.
I am implementing WPF MVVM Wizard and I am wondering about the right approach of performing a DoOperation when a new Wizard’s Page (UserControl) is loaded.
The DoOperation is implemented on the MyWizard.ViewModal class while the UserControl Load is happening at the MyWizard.View namespaces.
How can I connect between the UserControl loaded event to the DoOperation api?
I tried the following:
<xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
<i:Interaction.Triggers>
<i:EventTrigger EventName="Loaded">
<i:InvokeCommandAction Command="{Binding Path=RunOperation}"/
</i:EventTrigger>
</i:Interaction.Triggers>
RunOperation calls DoOperation.
it doesn’t work, RunOperation is not being called.
This is the right approach or there is a better way to perform an operation at the MyWizard.ViewModal class?
Your approach should work. Have you checked your output console for binding errors? Is RunOperation a command? Is the DataContext of the UserControl already set, when the Loaded event is raised? Have you implemented the triggers like this in your UC?
<UserControl x:Class="..."
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity">
<i:Interaction.Triggers>
<i:EventTrigger EventName="Loaded">
<i:InvokeCommandAction Command="{Binding Path=RunOperation}"/>
</i:EventTrigger>
</i:Interaction.Triggers>
<Grid>
...
</Grid>
</UserControl>
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>
How to fire RoutedEvents of TextBlock in ViewModel from code behind in wpf.
Kindly let me know, how I can bind routed events in wpf code behind. Thanks
Well I use this (you will need System.Windows.Interactivity in Silverlight, but I suspect it's similar in WPF):
xmlns:GalaSoft_MvvmLight_Command="clr-namespace:GalaSoft.MvvmLight.Command;assembly=GalaSoft.MvvmLight.Extras.SL4"
xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
<TextBlock Text="{Binding InputValue, Mode=TwoWay}">
<i:Interaction.Triggers>
<i:EventTrigger EventName="GotFocus">
<GalaSoft_MvvmLight_Command:EventToCommand Command="{Binding InputValueGotFocusCommand}" />
</i:EventTrigger>
</i:Interaction.Triggers>
</TextBlock>
You can do this easy in Blend
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