TPropertyBag<Derived> (Compact 2013)

3/28/2014

This C++ template class manages access to properties in a property bag for a data source object and provides access to the PropertyChanged event for the property bag.

Syntax

template<typename Derived>
class __declspec(novtable) TPropertyBag : public iXRPropertyBagBinding

Inheritance Hierarchy

iXRPropertyBagBinding

     TPropertyBag<Derived>

Template Parameters

• Derived
  The name of the class type for the data source object that implements TPropertyBag<Derived>.

Members

The following tables list any methods and fields that belong to this class.

Methods

Fields

Thread Safety

The TPropertyBag.RegisterBoundProperty(const ce.wstring&,iXRPropertyBinding &) method is thread-safe after you call TPropertyBag.BeginRegisterProperties. When you are finished with registering properties, you must call TPropertyBag.EndRegisterProperties. Other methods on this interface are not thread-safe when you are registering new properties or updating property values. While you are registering properties or updating property values, implement single-threading and block other operations until the task is finished. For example, use XRAutoCriticalSection.

Remarks

TPropertyBag<Derived> is a property bag, in which an object stores its properties, and is a helper extension for IXRPropertyBag.

To set a data source object that implements TPropertyBag<Derived> as the data context for a UI element, call IXRFrameworkElement::SetDataContext. Then, to bind property data to a UI element, either call IXRFrameworkElement::SetBinding or use a Binding Markup Extension in Microsoft Silverlight 3 XAML.

In contrast to its superinterface IXRPropertyBag, TPropertyBag<Derived> provides an IXRCustomEvent object, which you access by calling TPropertyBag.GetPropertyChangedEvent(IXRCustomEvent<XRPropertyChangedCustomEventArgs, IXRPropertyBag>**).

The functionality in this class differs from Microsoft Silverlight 3. XAML for Windows Embedded does not support C++ equivalent classes for the System.Reflection namespace in Microsoft Silverlight 3 for invoking programming elements by name. Instead, you can use this class to resolve a data source property by name, instead of by a C++ object instance.

To resolve properties by name, you must first register the properties with the property bag by calling TPropertyBag.RegisterBoundProperty(const ce.wstring&,iXRPropertyBinding &).

TPropertyBag<Derived> implements an interface map so that you can access its methods through interfaces obtained by using IUnknown::QueryInterface. TPropertyBag<Derived> defines the interface map by using the BEGIN_QI_MAP and END_QI_MAP macros.

Make sure that your custom data source object inherits from TPropertyBag<Derived>. The data source object must define a set of iXRPropertyBinding derived objects that each represent properties whose values are displayed in data-bound elements in the UI.

When you use TPropertyBag <Derived> with a NULL value, a debug break occurs as a warning that your code might later fail. To determine the source of your error, check the HRESULT that was returned when you set TPropertyBag <Derived>.

Obtaining a Pointer

To obtain a TPropertyBag<Derived> pointer on a data source object of type Derived, call TPropertyBag.CreateInstance(Derived * *). To obtain a TPropertyBag<Derived> pointer on a data source object in a data source collection, call XRValueCollectionT.GetItem(int,ItemType *).

Example

The following code example shows the interface mapping for TPropertyBag<Derived>.

template<typename Derived>
class __declspec(novtable) TPropertyBag : public iXRPropertyBagBinding
{
    BEGIN_QI_MAP()
        QI_MAP_INTERFACE(Derived)
        QI_MAP_INTERFACE(TPropertyBag)
        QI_MAP_INTERFACE(IXRPropertyBag)
    END_QI_MAP()

Requirements

See Also

Reference

Classes for Populating UI Elements with Data
TBoundProperty<PropertyType>
TBoundProperty<BSTR>
TBoundPointerProperty<PropertyType>