For example, if your control is a Button , that control has a Click event that's specifically intended for when the user invokes the button's action. Or if your element isn't a button but you're handling and event for an element's primary action, you would handle Tapped. Gesture events can be specifically disabled on individual elements by setting properties such as IsTapEnabled. You might disable the gesture events if you are processing manipulations, but you typically don't need to disable gesture events if you're handling pointer events.
Pointer events can't be specifically disabled, but you can choose to not handle them. Don't rely on PointerPressed and PointerReleased events always occurring in pairs.
To function properly, your app must listen for and handle all events that represent likely conclusions to the Press action.
Some of the reasons why you might not get a PointerReleased occurrence are:. Skip to main content. This browser is no longer supported. Download Microsoft Edge More info. Contents Exit focus mode. Pointer Pressed Event Reference Is this page helpful? Please rate your experience Yes No. Any additional feedback? Namespace: Windows. Submit and view feedback for This product This page.
View all page feedback. In this article. Sign in. Your cart. Page 1 of 7 Next. NET Framework 4 , you'll learn to use the built-in functionality of the Microsoft. The default XAML namespace defines which elements you can declare without qualifying them by a prefix. For typical Windows Runtime app projects, this default namespace contains all the built-in XAML vocabulary for the Windows Runtime that's used for UI definitions: the default controls, text elements, XAML graphics and animations, databinding and styling support types, and so on.
Here's a snippet that shows a template-created Page root of the initial page for an app showing the opening tag only, and simplified. It declares the default namespace and also the x namespace which we'll explain next. This namespace includes elements and concepts that are defined by the XAML language specification. Here are the most common ones:. You can define your own custom types in your app's programming language and then reference your custom types in XAML markup.
Support for extension through custom types is fundamentally built-in to how the XAML language works. Frameworks or app developers are responsible for creating the backing objects that XAML references. Neither frameworks nor the app developer are bound by specifications of what the objects in their vocabularies represent or do beyond the basic XAML syntax rules.
Use that prefix in element usages to reference the types that were defined in your library. You declare prefix mappings as xmlns attributes, typically in a root element along with the other XAML namespace definitions. To make your own namespace definition that references custom types, you first specify the keyword xmlns: , then the prefix you want.
The value of that attribute must contain the keyword using: as the first part of the value. The remainder of the value is a string token that references the specific code-backing namespace that contains your custom types, by name. A colon character : goes between the prefix and the entity to be referenced within the XAML namespace. For example, the attribute syntax to map a prefix myTypes to the namespace myCompany.
You often see XAML files that define the prefixes "d" for designer namespace and "mc" for markup compatibility. Generally, these are for infrastructure support or to enable scenarios in a design-time tool.
Markup extensions often represent some kind of "shortcut" that enables a XAML file to access a value or behavior that isn't simply declaring elements based on backing types. Some markup extensions can set properties with plain strings or with additionally nested elements, with the goal of streamlining the syntax or the factoring between different XAML files.
This usage directs the XAML processing to escape from the general treatment of treating attribute values as either a literal string or a directly string-convertible value. Instead, a XAML parser calls code that provides behavior for that particular markup extension, and that code provides an alternate object or behavior result that the XAML parser needs. Markup extensions can have arguments, which follow the markup extension name and are also contained within the curly braces.
Typically, an evaluated markup extension provides an object return value. During parsing, that return value is inserted into the position in the object tree where the markup extension usage was in the source XAML.
For example you might use this in a control template for a CheckBox , which interprets null as an indeterminate check state triggering the "Indeterminate" visual state.
A markup extension generally returns an existing instance from some other part of the object graph for the app or defers a value to run time. Because you can use a markup extension as an attribute value, and that's the typical usage, you often see markup extensions providing values for reference-type properties that might have otherwise required a property element syntax.
Style property. By using markup extensions, every property that is settable in XAML is potentially settable in attribute syntax. You can use attribute syntax to provide reference values for a property even if it doesn't otherwise support an attribute syntax for direct object instantiation. Or you can enable specific behavior that defers the general requirement that XAML properties be filled by value types or by newly created reference types. Style property of a Border by using attribute syntax.
The FrameworkElement. Style property takes an instance of the Windows. Style class, a reference type that by default could not be created using an attribute syntax string.
0コメント