Andy (Steve) De GeorgeandGenevieve Warren
ea8529f082
* Add overview article for new WPF (#178) * Remove previous WPF .NET 5 content * Overview article * New article: Create new WPF project (#183) * Basic index file * Finish article for new project. * acro * markdown fix * Fix build errors * fix code lang * fix code lang * Add differences article for WPF (#186) * Fix VS version for create app * Add differences article * Minor * fix overview styles code * Add code langs for overview * Port Window Overview WPF article (#1011) * Add Window overview article * Add TOC * Remove temp code * Fix headers * Port final Windows related articles (#1015) * Initial test commit * Add system dialogs * 75% complete * Add images * Fix linter * Add to toc * Add more howto * Fix code * Add get/set main window * Add missing code * Add to toc * Fix warnings * Fix warnings * missing code * Update see also * fix xref * Migrate wpf net core controls-styles articles (#1023) * Migrate control-styles * Fix links * Fix links * Port databinding article. (#1022) * Migrated databinding overview * update toc * Fix links/snippets * fix links * Move to correct folder * Port initial resources docs (#1026) * initial resources docs * Build errors * Update dotnet-desktop-guide/net/wpf/systems/xaml-resources-overview.md Co-authored-by: Genevieve Warren <[email protected]> * Apply suggestions from code review Co-authored-by: Genevieve Warren <[email protected]> * Feedback * Add app article * Add system article * Minor * meta * fix toc * Apply suggestions from code review Co-authored-by: Genevieve Warren <[email protected]> Co-authored-by: Genevieve Warren <[email protected]> * Add xaml article * reformat redirect * Redirects * WPF update XAML article (#1031) * convert snippets * minor edits * minor * Fix warnings * Fixes #1028 * Fixes #1028 * Apply suggestions from code review Co-authored-by: Genevieve Warren <[email protected]> * update redirects Co-authored-by: Genevieve Warren <[email protected]> * minor updates to link * Readd migration article * Warning fixes * Fix lint * Minor updates * Fix warnings for TOC/YML * last warnings Co-authored-by: Genevieve Warren <[email protected]>
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title, description, ms.date, f1_keywords, helpviewer_keywords, ms.assetid
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| x:Null Markup Extension | Describes how the x:Null markup extension is handled by XAML. | 03/30/2017 |
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2e3ccc21-4996-481d-91b5-3910d8b3bfa3 |
x:Null Markup Extension
Specifies null as a value for a XAML member.
XAML Attribute Usage
<object property="{x:Null}" .../>
Remarks
The keyword for a null reference in C# and C++ is null. The Microsoft Visual Basic keyword for a null reference is Nothing, but you always use {x:Null} as the XAML usage regardless which code-behind language you associate with the XAML.
The x:Null markup extension has no settable properties.
A null usage is often associated with the XAML member exposure of a CLR xref:System.Nullable%601 value.
The x:Null markup extension, like all XAML markup extensions, uses the braces ({,}) for escaping the handling of attribute values to be other than literals or event-handler references. Attribute syntax is the syntax most frequently used with this markup extension. An object element syntax <x:Null /> is technically possible, but is rarely used because the x:Null markup extension has no positional parameters or construction arguments.
For information about markup extensions, see Markup Extensions and WPF XAML.
In .NET XAML Services, the handling for this markup extension is defined by the xref:System.Windows.Markup.NullExtension class.
WPF Usage Notes
Note that null is not necessarily the initial unset value for a reference-type dependency property. The initial default value can vary for each dependency property and can be based on property-specific metadata. Many dependency properties do not accept null as a value, either through markup or code because of their validation callback implementations. For more information about dependency properties, see Dependency Properties Overview.