I'm new to WPF and wrote this program to help with organising and cataloguing my books. I used a virtualizing wrap panel which displays perfectly until I sort the books.
Here is the view pre sort: Presorted Book List
Here is the view post sort: Sorted Book List
Here is the XAML for the DataTemplate:
<!-- DataTemplate for GridView -->
<DataTemplate x:Key="GridViewTemplate">
<ListView ItemsSource="{Binding FilteredBooks}"
SelectedItem="{Binding SelectedBook, Mode=TwoWay}"
SelectionChanged="OnBookSelected"
VirtualizingStackPanel.IsVirtualizing="True"
VirtualizingStackPanel.VirtualizationMode="Recycling">
<ListView.ItemsPanel>
<ItemsPanelTemplate>
<virtualizingWrapPanel:VirtualizingWrapPanel Orientation="Horizontal" />
</ItemsPanelTemplate>
</ListView.ItemsPanel>
<ListView.ItemTemplate>
<DataTemplate>
<StackPanel Width="160" Margin="5" ToolTip="{Binding Title}">
<Image Source="{Binding CoverImage}" Height="240" Width="160" Stretch="UniformToFill" Margin="0,0,0,5"/>
<TextBlock Text="{Binding Title}" TextAlignment="Center" FontWeight="Bold" TextWrapping="Wrap" />
<TextBlock Text="{Binding Author}" TextAlignment="Center" TextWrapping="Wrap" />
</StackPanel>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
and here is the function I used to sort the list.
public async Task FilterAndSortBooks()
{
var result = await Task.Run(() =>
{
IEnumerable<Book> filtered = Books;
// Apply filter based on the selected filter option
if (!string.IsNullOrWhiteSpace(SearchText))
{
filtered = SelectedFilter switch
{
"Title" => filtered.Where(book => book.Title.Contains(SearchText, StringComparison.OrdinalIgnoreCase)),
"Author" => filtered.Where(book => book.Author.Contains(SearchText, StringComparison.OrdinalIgnoreCase)),
"Release Year" => filtered.Where(book => book.Year.HasValue && book.Year.Value.ToString("yyyy").Contains(SearchText, StringComparison.OrdinalIgnoreCase)),
_ => filtered
};
}
// Apply sorting based on the selected sort option
filtered = SelectedSortOption switch
{
"Title" => filtered.OrderBy(book => book.Title),
"Author" => filtered.OrderBy(book => book.Author),
"Release Year" => filtered.OrderBy(book => book.Year),
_ => filtered
};
return filtered.ToList();
});
// Update FilteredBooks on the UI thread
Application.Current.Dispatcher.Invoke(() =>
{
FilteredBooks.Clear();
foreach (var book in result)
{
FilteredBooks.Add(book);
}
});
}
I want the sorted view to match the view presorted but can't figure out why it changes. Any help would be great.
Look at the first item in the "WrapPanel" (first image). How does its "size" compare to all the items that follow it? Is it bigger or smaller?
In the absence of an explicit "item" Height and / or Width, the "first" item (size) in the collection drives the "desired size" for all following items.
So, insure all items are the same size; or, the big ones come first; or, using specific Widths and / or Heights.