/// <summary>
/// Invoked when the effective property value of the ViewMode property changes.
/// </summary>
/// <param name="dependencyObject">The DependencyObject on which the property has changed value.</param>
/// <param name="dependencyPropertyChangedEventArgs">Event data that is issued by any event that tracks changes to the effective value of this
/// property.</param>
static void OnViewModePropertyChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs dependencyPropertyChangedEventArgs)
{
// Extract the ViewButton and the new view mode from the property change event arguments.
ViewButton viewButton = dependencyObject as ViewButton;
ViewMode viewMode = (ViewMode)dependencyPropertyChangedEventArgs.NewValue;
// This uses a table of image sources to match the image on the button with the mode selected.
viewButton.Icon = new Image()
{
Source = ViewButton.imageSourceTable[viewMode]
};
}
/// <summary>
/// Invoked when the effective property value of the Value property changes.
/// </summary>
/// <param name="dependencyObject">The DependencyObject on which the property has changed value.</param>
/// <param name="dependencyPropertyChangedEventArgs">Event data that is issued by any event that tracks changes to the effective value of this
/// property.</param>
static void OnValuePropertyChanged(DependencyObject dependencyObject, DependencyPropertyChangedEventArgs dependencyPropertyChangedEventArgs)
{
// Extract the ViewButton and the new view value from the property change event arguments.
ViewButton viewButton = dependencyObject as ViewButton;
Int32 viewValue = (Int32)dependencyPropertyChangedEventArgs.NewValue;
// This will snap the slider into a distinct position for a viewing mode. Note that any minimum or maximum can be used for the slider control and the
// scaling calculations will adjust.
foreach (Range range in ViewButton.viewRange)
{
if (range.Minimum <= viewValue && viewValue < range.Maximum)
{
viewButton.ViewMode = range.ViewMode;
}
}
}
/// <summary>
/// Initializes a new instance of the ViewButton class.
/// </summary>
public ViewButton()
{
// This will handle the part of the Gadget that acts like a button when it is clicked.
this.AddHandler(ButtonBase.ClickEvent, new RoutedEventHandler(this.OnButtonClick));
// If the actual value of a property hasn't changed, then the property change handler isn't called. This is a problem on initialization because if you
// try to set the property to an explicit value and that value is the same as the default for that property, then there's no implicit way to call the
// property change handler. This trick will force the button into a known state by explicitly calling the event handler.
ViewMode viewMode = (ViewMode)ViewButton.ViewModeProperty.DefaultMetadata.DefaultValue;
ViewButton.OnViewModePropertyChanged(this, new DependencyPropertyChangedEventArgs(ViewButton.ViewModeProperty, null, viewMode));
// This is the header for the button which is normally invisible when it is parked on the far side of the toolbar. It become visible on the right side
// and when it overflows.
this.Header = Properties.Resources.Views;
// This provides the tool tip for the button.
this.ToolTip = Properties.Resources.ChangeViewToolTip;
}