Matthias Herrmann Matthias Herrmann - 1 month ago 24
C# Question

Mvvm Light UWP Index Of Listitem When Button In ListItem Is Pressed

My issue:

I got a ListView which has a ItemTemplate; containing a DataTemplate with some

AppBarButtons
in it.
Now when the user is pressing one of the Buttons in the ListView the ListItem which is containing the button doesn't get highlighted.
This Problem also leads to the issue that I don't know how to get
the index of the listitem which is containing the button the user clicked.

ListItem:

One ListItem

The code in
Mainpage.xaml
:

<ListView.ItemTemplate>
<DataTemplate>
<StackPanel Orientation="Vertical">
<StackPanel Orientation="Horizontal">
<!-- Simplified, Left out other AppBarButtons -->
<AppBarButton Foreground="White" VerticalAlignment="Center"
Label="Navigate" Icon="Map" >
<interactivity:Interaction.Behaviors>
<core:EventTriggerBehavior EventName="Tapped">
<core:InvokeCommandAction Command="{Binding Main.OpenMapCommand, Mode=OneWay, Source={StaticResource Locator}}"></core:InvokeCommandAction>
</core:EventTriggerBehavior>
</interactivity:Interaction.Behaviors>
</AppBarButton>
</StackPanel>
</StackPanel>
</DataTemplate>
</ListView.ItemTemplate>


The command:

public RelayCommand OpenMapCommand
{
get
{
return _openMapCommand
?? (_openPaneCommand = new RelayCommand(
() =>
{
Debug.WriteLine("Opening map");
// Center on New York City
var uriNewYork = new Uri(@"bingmaps:?cp=40.726966~-74.006076");

// Launch the Windows Maps app
var launcherOptions = new Windows.System.LauncherOptions();
launcherOptions.TargetApplicationPackageFamilyName = "Microsoft.WindowsMaps_8wekyb3d8bbwe";
var success = Windows.System.Launcher.LaunchUriAsync(uriNewYork, launcherOptions);
}));
}
}


Whatan answer to this question needs to provide:


  • How to get the index of the ListItem which is containing the AppBarButton which has been pressed for being used in the relaycommand (be aware the ListItem doesn't get selected when the user is pressing the AppBarButton)


Answer

The DataContext within the ItemTemplate will be the item that you want to pass as a command parameter, so you should be able to just bind it to CommandParameter:

<core:InvokeCommandAction Command="{Binding Main.OpenMapCommand, Source={StaticResource Locator}}" CommandParameter="{Binding}"/>
_openPaneCommand = new RelayCommand(item =>
{
    ....
});