Jelle Capenberghs Jelle Capenberghs - 21 days ago 6
C# Question

Bind event to ViewModel

I am using WPF and PRISM framework for my application. The pattern I am using is MVVM (Model - View - ViewModel) and I am trying to bring the MouseLeftButtonUp event from the code-behind in the View to the ViewModel (so the event will be according the MVVM rules). For now I have this:

View.xaml:

<DataGrid x:Name="employeeGrid" Height="250" Margin="25,0,10,0" ItemsSource="{Binding DetacheringenEmployeesModel}" IsReadOnly="True" ColumnHeaderStyle="{DynamicResource CustomColumnHeader}" AutoGenerateColumns="False" RowHeight="30">
<i:Interaction.Triggers>
<i:EventTrigger EventName="MouseLeftButtonUp">
<i:InvokeCommandAction Command="{Binding EmployeeGrid_MouseLeftButtonUp}" />
</i:EventTrigger>
</i:Interaction.Triggers>
<DataGrid.Columns>


View.xaml.cs (code-behind):

public partial class UC1001_DashBoardConsultants_View
{
public UC1001_DashBoardConsultants_View(UC1001_DashboardConsultantViewModel viewModel)
{
InitializeComponent();
DataContext = viewModel;
}
}


ViewModel.cs:

public void EmployeeGrid_MouseLeftButtonUp(object sender, MouseButtonEventArgs e)
{
// insert logic here
}


The main idea is, when I click on a cell in the DataGrid, the event will fire. I first tried it in the code behind, and it worked. I got so far with the EventTriggers, but when I debug and click on a cell, my debugger doesn't come into the method.

Does anyone have an idea how to fix this? Thanks in advance!

PS: Does it also work with the (object sender) parameter when I do it like that? Because I need the DataGrid in my ViewModel to get the ActiveCell I just clicked on.

EDIT:

The event-binding worked with the Command!

I have this in my DataGrid:

<DataGridTextColumn Header="Okt" Width="*" x:Name="test" >
<DataGridTextColumn.ElementStyle>
<Style TargetType="{x:Type TextBlock}">
<Setter Property="Tag" Value="{Binding Months[9].AgreementID}"/>


How can I bind the Tag property to the ViewModel? I know it's already bound from the ViewModel, but as you can see the value comes from an Array/List and per column the value is different.

sll sll
Answer

InvokeCommandAction requires the ICommand to be bound not an event handler as you've bound (EmployeeGrid_MouseLeftButtonUp).

So you can introduce a command in ViewModel and bind to it:

View Model:

public ICommand SomeActionCommand { get; set; }

XAML:

<i:InvokeCommandAction Command="{Binding SomeActionCommand}" />