Controls with Custom Styles Fall Back to the Old Look Under the WPF Fluent Theme
Why controls carrying a custom Style keep the legacy look under the Fluent theme, how BasedOn fixes it, and which placements leave BasedOn unresolved.
WPF
Articles on WPF and XAML — data binding, controls, styling, virtualization, and UI behavior. Each one starts from a concrete problem met while building a Windows desktop application, explains why the behavior occurs, and works through the implementation and its trade-offs.
WPF articles (30)
All articles →Causes of a Stale ICollectionView Filter in WPF and Choosing Between Refresh and Live Filtering
The filter is correct right after assignment, yet an item property change leaves the list stale. Refresh and live filtering compared on .NET 10.
Why a WPF RadioButton Bound to an Enum Shows No Initial Selection — The Role of GroupName
A ViewModel holds the right enum value, yet its radio button appears cleared. Omitting GroupName merges separate enum groups into one. Measured cause and fix.
Diagnosing a WPF Process That Stays Alive After the Window Closes — ShutdownMode and Foreground Threads
The window is gone but the process stays in Task Manager. WPF shutdown has two gates, app shutdown and process exit, and the fix depends on which one stalled.
Binding to a WPF UserControl's Own Dependency Property from Inside the Control
A dependency property gets its value, yet the internal {Binding Title} stays blank. RelativeSource, ElementName, and inner-root delegation compared on .NET 10.
Why WPF Validation Errors Are Not Displayed, and Choosing Between IDataErrorInfo and INotifyDataErrorInfo
Validation code runs but nothing appears. The causes are isolated on .NET 10: the ValidatesOnDataErrors default, a missing adorner layer, and update timing.
Selecting and Expanding a WPF TreeView Node from Code, and Why SelectedItem Is Read-Only
TreeView.SelectedItem cannot be assigned or data-bound: the selection lives on TreeViewItem. Style binding and ItemContainerGenerator are compared.
Binding to the Parent DataContext from Inside a WPF DataTemplate
Bindings inside a DataTemplate resolve against the item, not the parent view model. Comparing RelativeSource, ElementName, x:Reference, and PlacementTarget.
Why WPF Style Triggers and DataTriggers Do Not Apply — Dependency Property Value Precedence
A style trigger that never applies is usually outranked by a local value in XAML. Covers value precedence and the Setter, SetCurrentValue and ClearValue fixes.
Releasing the Image File Locked by BitmapImage in WPF with BitmapCacheOption.OnLoad
An image file shown through BitmapImage cannot be deleted or overwritten. This covers the default caching behavior behind it and the OnLoad fix.
Fixing a RelayCommand Whose CanExecute Does Not Update the Button State in WPF
A custom RelayCommand's button stays stuck when CanExecuteChanged is never raised. This compares delegating to RequerySuggested with raising it manually.
Calling TextBox UpdateSource from the View in WPF: Implementation and Pitfalls
Calling GetBindingExpression().UpdateSource() from the View has pitfalls: null returns, bulk updates, wrong direction, and MVVM, grounded in official docs.
Controlling When TextBox Input Reaches the Source with UpdateSourceTrigger in WPF
TextBox.Text defaults to LostFocus, so typed input may never reach the ViewModel. This covers the three UpdateSourceTrigger values, their timing, and pitfalls.
Fixing the Cross-Thread Exception When Updating an ObservableCollection in WPF
Modifying a bound ObservableCollection off the UI thread throws a NotSupportedException from CollectionView affinity. This covers the cause and two fixes.
Hiding the Clear Button on a Fluent-Themed WPF TextBox
How to hide the clear button a Fluent-themed WPF TextBox shows on focus, without changing input behavior, on .NET 10 and .NET 9.
Why a WPF ScrollViewer Does Not Scroll and How to Fix It
A ScrollViewer inside a StackPanel does not scroll because the StackPanel never constrains its height. This covers the cause and the Grid and DockPanel fixes.
Formatting Numbers, Currency, and Dates with Binding.StringFormat in WPF
A practical guide to formatting numbers, currency, and dates with Binding.StringFormat without a converter, including culture and ContentControl constraints.
Reading WPF Binding Errors and Diagnosing Them with the Output Window
When a WPF Binding fails silently, Visual Studio logs it as a trace. This article covers reading the message, raising the trace level, and common patterns.
How to Reset DataGrid Sorting in WPF
Practical ways to reset WPF DataGrid sorting, including explicit clearing, Sorting-event control, CollectionView handling, and a reusable Behavior.
Why StaticResource Changes Are Not Reflected in WPF and How to Fix It
StaticResource resolves its value at XAML load time, so runtime changes have no effect. Use DynamicResource when the value must update at runtime.
Why WPF Slows Down with Many Labels and When to Switch to TextBlock
Why rendering slows down when many WPF Labels are used, explained through measured visual tree data. Covers the gap against TextBlock, the extra cost imposed...
Why WPF Label Hides Underscores and How to Fix It
When a string containing an underscore (_) is set on a WPF Label, the character disappears from the screen. This article explains the underlying ContentPrese...
Switching Controls Between Display and Edit Modes in WPF DataGrid Cells
Use DataGridTemplateColumn with CellTemplate and CellEditingTemplate to separate display UI from editing UI in WPF DataGrid.
Fixing a WPF Tray ContextMenu That Does Not Close on Focus Loss
This article explains how TreePaste resolved a tray ContextMenu that stayed visible until an item was clicked by combining StaysOpen=false with SetForeground...
Applying Fluent Design in WPF Without Extra Libraries
This article explains how to apply Fluent styling in WPF using only built-in features, with App.xaml theme setup and SystemColors-based color tracking.
How to Display Selectable, Copyable Read-Only Text in WPF
Learn how to use a read-only TextBox as a TextBlock replacement in WPF so text remains selectable and copyable without allowing edits.
WPF ComboBox ItemsSource Binding Patterns and Selected Value Retrieval
The correct combination of DisplayMemberPath, SelectedItem, SelectedValue, and SelectedValuePath depends on the element type bound to ItemsSource. This artic...
How to Prevent SelectedItems from Appearing Lost in a Virtualized WPF ListBox
Why ListBox selection appears to vanish under UI virtualization, and how an IsSelected-based MVVM pattern keeps it stable. Includes measured evidence that th...
How to Implement DataGrid Sorting in WPF
Learn the basics of DataGrid sorting and practical implementation patterns for real-world WPF applications.
Customising the DatePicker Display Format in WPF
A practical guide to changing the date display format of WPF DatePicker from XAML, code-behind, and a value converter.