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ContextItem |
The ContextItem class is the base class from which all context items must derive. |
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ContextItem< (Of < ( <'T> ) > ) > |
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ContextItemCollection |
The ContextItemCollection class maintains a set of context items. A context item represents a piece of transient state in a designer. ContextItems must define an empty constructor. This empty constructor version of a context item represents its default value, and will be the value returned from GetItem if the context item manager does not contain a context item of the requested type. The ContextItemCollection supports context layers. A context layer is a separation in the set of context items and is useful when providing modal functions. For example, when switching modes in the designer to show the tab order layout it may be desirable to disable adding items from the toolbox and change the user mouse and keyboard gestures to focus on setting the tab order. Rather than grabbing and storing context items before replacing them with new values, a developer can simply call CreateLayer. Once the layer is created, all subsequent context changes go to that layer. When the developer is done with the layer, as would be the case when a user switches out of tab order mode, she simply calls Remove on the layer. This removes all context items that were added to the layer and restores the context to its previous set of values before the layer was created. |
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ContextLayer |
The items in the context item manager are divided into layers. A layer may be isolated, in which it does not inherit context from previous layers, or normal, in which it does. Once a layer is created new context items can be set into that layer. When the layer is removed, all the prior context items come back. |
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EditingContext |
The EditingContext class contains contextual state about a designer. This includes permanent state such as list of services running in the designer. It also includes transient state consisting of context items. Examples of transient context item state include the set of currently selected objects as well as the editing tool being used to manipulate objects on the design surface. The editing context is designed to be a concrete class for ease of use. It does have a protected API that can be used to replace its implementation. |
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Selection< (Of < ( <'T, Owner> ) > ) > |
The Selection class defines a selection of T. Selections consist of zero or more items. The first item in a selection is defined as the "primary" selection, which is used when one object in a group must be used as a key. |
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ServiceCollection |
The service collection implements IServiceProvider and provides access to services offered by the editing context. |
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