WPF Binding Without INotifyPropertyChanged: Why the Source Stays in Memory
With a OneWay or TwoWay binding to a non-INotifyPropertyChanged source, .NET 10 collects the closed window but keeps the source as a PropertyDescriptor key.
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 (41)
All articles →Where Exceptions from CommunityToolkit.Mvvm AsyncRelayCommand Go in WPF, and What FlowExceptionsToTaskScheduler Changes
Uncaught button-run AsyncRelayCommand errors hit DispatcherUnhandledException; FlowExceptionsToTaskScheduler held them, view model alive, until a rerun GC.
Why CommunityToolkit.Mvvm ObservableValidator Shows No Validation Error on Startup in WPF
ObservableValidator shows no error on an empty required field at startup: HasErrors is False until validation runs. ValidateAllProperties fixes it two ways.
Why InvalidateRequerySuggested Does Not Update CommunityToolkit.Mvvm and Prism Commands in WPF
The Toolkit RelayCommand and Prism DelegateCommand keep a button disabled even after InvalidateRequerySuggested. Measurements show why, and what updates them.
Why Task.Result Freezes a WPF App and When ConfigureAwait(false) Does Not Help
Blocking on .Result on the WPF UI thread freezes the window when the code after an await must resume there. ConfigureAwait(false) and Task.Run can fail too.
Exceptions WPF's DispatcherUnhandledException Never Sees — Where Thread, Task and async void Exceptions Go
A new Thread exception ends a WPF app despite Handled = true, and an unawaited Task's exception reaches nothing at first. The first layer to catch it decides.
Why a WPF DataGrid Edit Does Not Reach the ViewModel When Save Is Clicked, and How to Use CommitEdit
Saving from a ToolBar or Menu while a WPF DataGrid cell is in edit mode stores the old value, and one CommitEdit() call during a cell edit leaves the row open.
How User Input Silently Removes a WPF Binding Written Without Mode
Bindings to TreeViewItem.IsExpanded or ColumnDefinition.Width without Mode break after the expander button or a GridSplitter is used. Mode=TwoWay keeps them.
Finding What Turns Off UI Virtualization in WPF
WPF list virtualization turns off silently through placement, the items panel, or scroll settings. Measured with 1,000 items, with diagnosis steps and fixes.
Why WPF Input Limits Such as MaxLength Do Not Apply to Values Set from Code or Bindings
Limits such as MaxLength and DisplayDateStart do not stop values from code or bindings. Three paths are measured on .NET 10, and checks move to the view model.
Diagnosing Why Parts of a WPF App Stay Light After Switching ThemeMode at Runtime
Parts of a WPF app stay Light after a ThemeMode switch to Dark. Measured causes: a window-level or nested Fluent dictionary, StaticResource, or SystemColors.
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.
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 enum groups under one parent. 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 in a vertical StackPanel does not scroll because the StackPanel never constrains its height. 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 at XAML load time, so replacing the resource at runtime leaves existing references unchanged. DynamicResource follows such replacements.
Why WPF Slows Down with Many Labels and When to Switch to TextBlock
Why many WPF Labels slow rendering, from measured visual trees: the gap against TextBlock, underscore costs, and whether it survives virtualization.
Why WPF Label Hides Underscores and How to Fix It
Why a WPF Label hides underscores: ContentPresenter.RecognizesAccessKey, which other controls are affected, and four measured workarounds with how to choose.
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
How TreePaste fixed a tray ContextMenu that stayed open until an item was clicked, by combining StaysOpen=false with SetForegroundWindow() before showing it.
Applying Fluent Design in WPF Without Extra Libraries
Fluent styling in WPF with built-in features only: App.xaml theme setup, Fluent theme brushes that follow light and dark, and what SystemColors do not follow.
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 right mix of DisplayMemberPath, SelectedItem, SelectedValue and SelectedValuePath depends on the ItemsSource element type. Covers five binding patterns.
How to Prevent SelectedItems from Appearing Lost in a Virtualized WPF ListBox
Why ListBox selection appears lost under UI virtualization, why an ItemContainerStyle binding alone fails, and how IsSelected with SelectionChanged fixes it.
How to Implement DataGrid Sorting in WPF
Covers built-in column-header sorting in the WPF DataGrid, sorting from code-behind, and custom sort logic with ListCollectionView.CustomSort.
Customising the DatePicker Display Format in WPF
Fixing the WPF DatePicker format with a DatePickerTextBox style, escape separators in XAML, why setting Text in code-behind fails, and when a converter fits.