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Properties display grid

  • Artikkeli

The Properties window displays fields within a grid. The left column contains the property names; the right column contains the property values.

Work with the grid

The two-column list shows configuration-independent properties that can be changed at design time and their current settings. Note that all properties might not be shown. A property can be set as hidden, for example, by implementing the HideProperty method. Specifically, to hide properties that have child properties:

  1. Set the pfDisplay parameter in DisplayChildProperties to FALSE.

  2. Set the pfHide parameter in HideProperty to TRUE.

To push information to the Properties window, the IDE uses ISelectionContainer. ISelectionContainer is called by VSPackages for each window that contains selectable objects with related properties to be displayed in the Properties window. Solution Explorer's implementation of ISelectionContainer calls GetProperty using __VSHPROPID.VSHPROPID_BrowseObject in your project hierarchy to acquire the browseable objects in the hierarchy.

If your VSPackage does not support __VSHPROPID.VSHPROPID_BrowseObject, the IDE attempts to use GetProperty using the value for __VSHPROPID.VSHPROPID_SelContainer that the hierarchy item or items supply.

Your project VSPackage does not need to create ISelectionContainer because the IDE-supplied window package that implements it (for example, Solution Explorer) constructs ISelectionContainer on its behalf.

ISelectionContainer consists of three methods that are called by the IDE:

  • CountObjects contains the number of objects selected to be displayed in the Properties window.

  • GetObjects returns the IDispatch objects that are selected to be displayed in the Properties window.

  • SelectObjects makes it possible for any of the objects returned by GetObjects to be selected by the user. This allows the VSPackage to visually update the selection displayed to the user in the UI.

The Properties window extracts information from the IDispatch objects to retrieve the properties being browsed. The Properties browser uses IDispatch to ask the object what properties it supports by querying ITypeInfo, which is obtained from IDispatch::GetTypeInfo. The browser then uses these values to populate the Properties window and change the values for individual properties displayed in the grid. The properties information is maintained within the object itself.

Because the returned objects support IDispatch, the caller can obtain information such as the object's name by calling either IDispatch::Invoke or ITypeInfo::Invoke with a predefined dispatch identifier (DISPID) that represents the desired information. Declared DISPIDs are negative to ensure they do not conflict with user-defined identifiers.

The Properties window displays different types of fields depending on the attributes of specific properties of a selected object. These fields include edit boxes, drop-down lists, and links to custom editor dialog boxes.

  • Values contained in an enumerated list are retrieved by a GetObjects query to IDispatch. Values obtained from an enumerated list can be changed in the properties grid by double-clicking the field name, or by clicking the value and selecting the new value from the drop-down list. For properties that have predefined settings from enumerated lists, double-clicking the property name in the Properties list cycles through the available choices. For predefined properties with only two choices, such as true/false, double-click the property name to switch between the choices.

  • If HasDefaultValue is false, indicating that the value has been changed, the value is displayed in bold text. CanResetPropertyValue is used to determine if the value can be reset to the original value. If so, you can change back to the default by right-clicking the value and choosing Reset from the menu displayed. Otherwise, you have to change the value back to the default manually. IVsPerPropertyBrowsing also allows you to localize and hide the names of properties displayed during design time, but does not affect the property names displayed during run time.

  • Clicking the ellipsis (...) button displays a list of property values from which the user can select (such as a color picker or font list). IProvidePropertyBuilder provides these values.

See also