How do I populate Items in collection view from model view if I am using file picker? - maui

Question

I am trying to select some files from file picker . Once I select them I want to show them in my collection view. If I am trying to achieve this thing from code behind then it is working fine but if I am trying it from MVVM then it is not populating the files I have selected.
and the reason I am trying to do it with MVVM is that I want to navigate to the next page with all selected files.
Thanks.
Here is my code:
MainPage.xaml
<CollectionView Grid.ColumnSpan="2" Grid.Row="1"
SelectionMode="Single" x:Name="myCollection"
VerticalOptions="FillAndExpand"
VerticalScrollBarVisibility="Always"
ItemTemplate="{StaticResource appDataTemplate}"
ItemsSource="{Binding Items}">
</CollectionView>
Here I have binded my context.
MainPage.Xaml.cs
public MainPage(FileViewModel vm)
{
InitializeComponent();
BindingContext = vm;
}
And this is my viewModel:`[ObservableProperty]
List sourceData;
public List<Item> Items
{
get { return sourceData; }
set
{
sourceData = value;
}
}
public FileViewModel(IFolderPicker folderPicker)
{
sourceData = Items ;
_folderPicker = folderPicker;
}`
public async void Add_File(object sender, EventArgs e)
{
var CustomFileType = new FilePickerFileType(new Dictionary<DevicePlatform,
IEnumerable<String>>
{
//logic
});
var results = await FilePicker.PickMultipleAsync(new PickOptions
{
FileTypes = CustomFileType,
});
sourceData = null;
foreach (var result in results)
{
FileInfo fileInfo = new FileInfo(result.FullPath);
double size = fileSize(fileInfo);
bool fileExist = false;
if (Items != null)
{
foreach (Item item in Items)
{
if (item.FilePath.Equals(result.FullPath))
{
fileExist = true;
break;
}
}
}
else
{
Items= new ObservableCollection<Item>();
}
if (!fileExist)
{
Items.Add(new Item
{
FilePath = result.FullPath,
FileSize = size
});
}
else
{
Items= sourceData;
// await DisplayAlert("Alert", "File already exist!", "Ok");
}
}
Items = sourceData;
}
Same code is working file if I put the view models code in code behind like below:
private async void Add_File(object sender, EventArgs e)
{
var CustomFileType = new FilePickerFileType(new Dictionary<DevicePlatform,
IEnumerable<String>>
{
{ DevicePlatform.WinUI, new[]{"ics"} },
});
var results = await FilePicker.PickMultipleAsync(new PickOptions
{
FileTypes = CustomFileType,
});
myCollection.ItemsSource = null;
foreach (var result in results)
{
FileInfo fileInfo = new FileInfo(result.FullPath);
double size = fileSize(fileInfo);
bool fileExist = false;
foreach (Item item in Items)
{
if (item.FilePath.Equals(result.FullPath))
{
fileExist = true;
break;
}
}
if (!fileExist)
{
Items.Add(new Item
{
FilePath = result.FullPath,
FileSize = size
});
}
else
{
myCollection.ItemsSource = Items;
await DisplayAlert("Alert", "File already exist!", "Ok");
}
}
myCollection.ItemsSource = Items;
}
But it is not working with file view model.
I am not able to populate the collection view from view model.