Pooja PoojariandAndy De George
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* Updated H2 and column headers. * Metadata update. * Minor edits. * Apply suggestions from code review Co-authored-by: Andy (Steve) De George <[email protected]>
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title, description, ms.date, ms.custom, f1_keywords, helpviewer_keywords, ms.assetid
| title | description | ms.date | ms.custom | f1_keywords | helpviewer_keywords | ms.assetid | ||||||
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| x:ClassModifier Directive | Learn about the x:ClassModifier Directive. | 03/30/2017 | devdivchpfy22 |
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x:ClassModifier Directive
Modifies XAML compilation behavior when x:Class is also provided. Specifically, instead of creating a partial class that has a Public access level (the default), the provided x:Class is created with a NotPublic access level. This behavior affects the access level for the class in the generated assemblies.
XAML Attribute Usage
<object x:Class="namespace.classname" x:ClassModifier="NotPublic">
...
</object>
XAML Values
| Value | Description |
|---|---|
| NotPublic | The exact string to pass to specify xref:System.Reflection.TypeAttributes.Public?displayProperty=nameWithType versus xref:System.Reflection.TypeAttributes.NotPublic?displayProperty=nameWithType varies, depending on the code-behind programming language that you use. See Remarks. |
Dependencies
x:Class must also be provided on the same element, and that element must be the root element in a page. For more information, see [MS-XAML] Section 4.3.1.8.
Remarks
The value of x:ClassModifier in .NET XAML Services usage varies by programming language. The string to use depends on how each language implements its xref:System.CodeDom.Compiler.CodeDomProvider and the type converters it returns to define the meanings for xref:System.Reflection.TypeAttributes.Public?displayProperty=nameWithType and xref:System.Reflection.TypeAttributes.NotPublic?displayProperty=nameWithType, and whether that language is case sensitive.
-
For C#, the string to pass to designate xref:System.Reflection.TypeAttributes.NotPublic?displayProperty=nameWithType is
internal. -
For Microsoft Visual Basic .NET, the string to pass to designate xref:System.Reflection.TypeAttributes.NotPublic?displayProperty=nameWithType is
Friend. -
For C++/CLI, no targets exist that support compiling XAML; therefore, the value to pass is unspecified.
You can also specify xref:System.Reflection.TypeAttributes.Public?displayProperty=nameWithType (public in C#, Public in Visual Basic); however, specifying xref:System.Reflection.TypeAttributes.Public?displayProperty=nameWithType is infrequently done because xref:System.Reflection.TypeAttributes.Public?displayProperty=nameWithType is already the default behavior.
Other values with equivalent user code access-level restrictions, such as private in C#, are not relevant for x:ClassModifier because nested class references are not supported in XAML, and therefore, the xref:System.Reflection.TypeAttributes.NotPublic?displayProperty=nameWithType modifier has the same effect.
Security Notes
The access level as declared in x:ClassModifier is still subject to interpretation by particular frameworks and their capabilities. WPF includes capabilities to load and instantiate types where x:ClassModifier is internal, if that class is referenced from a WPF resource through a pack URI reference. As a consequence of this case and potentially others like it implemented by other frameworks, do not rely exclusively on x:ClassModifier to block all possible instantiation attempts.