Xamarin Forms ListView ItemTapped to object from ViewModel

Question

I have a problem. I have created a ListView with an ItemSource from my ViewModel. Now the ItemSource is an ObservableCollection<KnownDevice> with a few objects called KnownDevice . In my ListView I have set: ItemTapped="rowDevice_Clicked" with the following function:

private void rowDevice_Clicked(object sender, ItemTappedEventArgs e)
{
    ListView listView= (ListView)sender;
}

But now I need to know which KnownDevice was clicked.

How can I do that?

Answer 1

just make another single instance of your KnownDevice

public ObservableCollection<KnownDevice> ThisIsMySelectionList {get; set;}
public KnownDevice ThisIsTheSelectedDeviceFromList {get; set;}

Then, in your list definition

<ListView 
   ItemsSource="{Binding ThisIsMySelectionList}"
   SelectedItem="{Binding ThisIsTheSelectedDeviceFromList}" >

   .. rest of your column definitions to show

</ListView>

As an item is tapped/selected from the list, it is bound to the public get/set of "ThisIsTheSelectedDeviceFromList" as bound to the SelectedItem value

I'm sure there are others who can point to a more direct way, but within your getter/setter, you can point to the app object yourself, such as

public KnownDevice ThisIsTheSelectedDeviceFromList 
{
   get { return ((YourNamespace.App)App).YourKnownDeviceProperty; }
   set {((YourNamespace.App)App).YourKnownDeviceProperty = value; }
}

So here, I am forcing a typecast to specifically YOUR App by qualifying your project namespace.app of the static app object, then your property. You can get and set directly as needed.

Answer 2

在rowDevice_Clicked 中添加这行代码

var device = e.Item as KnownDevice

Answer 3

You need to create a property selectedDevice and bind that to SelectedItem of listview, below is my code hope it will be helpful for you.

ListView XAML :

<ListView HasUnevenRows="True" 
          ItemsSource="{Binding KnownDeviceItems}" 
          SelectedItem="{Binding SelectedKnownDevice}"
          SeparatorVisibility="None">
        <ListView.ItemTemplate>
            <DataTemplate>
                <ViewCell>
                    //code here for cell
                </ViewCell>
            </DataTemplate>
        </ListView.ItemTemplate>
    </ListView>

ViewModel Properties :

private ObservableCollection<KnownDevice> knownDeviceItems;
    public ObservableCollection<KnownDevice> KnownDeviceItems
    {
        get { return knownDeviceItems; }
        set
        {
            knownDeviceItems = value;
            OnPropertyChanged();
        }
    }

    private KnownDevice selectedKnownDevice;
    public KnownDevice SelectedKnownDevice
    {
        get { return selectedKnownDevice; }
        set
        {
            selectedKnownDevice = value;
            OnPropertyChanged();
        }
    }

Thanks