DrawingAttributes.PropertyDataChanged Olay
Tanım
Özellik verileri ' den eklendiğinde veya kaldırıldığında oluşur StrokeCollection .Occurs when property data is added or removed from the StrokeCollection.
public:
event System::Windows::Ink::PropertyDataChangedEventHandler ^ PropertyDataChanged;
public event System.Windows.Ink.PropertyDataChangedEventHandler PropertyDataChanged;
member this.PropertyDataChanged : System.Windows.Ink.PropertyDataChangedEventHandler
Public Custom Event PropertyDataChanged As PropertyDataChangedEventHandler
Public Event PropertyDataChanged As PropertyDataChangedEventHandler
Olay Türü
Örnekler
Aşağıdaki örnek, üç boyutlu bir efekt çizebileceğiniz özel bir konturun bir parçasıdır.The following example is part of a custom stroke that can draw a three-dimensional effect. Vuruş, öğesine ait olan adlı özel bir özelliği tanımlar ve depolar Shadowed
DrawingAttributes .The stroke defines and stores a custom property called Shadowed
, which belongs to DrawingAttributes. Shadowed
Özellik değiştiğinde, PropertyDataChanged olay işleyicisi, OnInvalidated konturun yeniden çizilmesini neden olan yöntemini çağırır.When the Shadowed
property changes, the PropertyDataChanged event handler calls the OnInvalidated method, which causes the stroke to be redrawn.
class ShadowedStroke : Stroke
{
// Be sure to pass in the DrawingAttributes when you create the stroke to
// subscribe to the PropertyDataChaned event.
public ShadowedStroke(StylusPointCollection stylusPoints, DrawingAttributes drawingAttributes)
: base(stylusPoints, drawingAttributes)
{
this.DrawingAttributes.PropertyDataChanged += new PropertyDataChangedEventHandler(DrawingAttributes_PropertyDataChanged);
}
Guid shadow = new Guid("12345678-9012-3456-7890-123456789012");
public bool Shadowed
{
// Return the value of the custom property, shadow.
// If there is no custom property, return false.
get
{
if (!this.DrawingAttributes.ContainsPropertyData(shadow))
{
return false;
}
object propertyData = this.DrawingAttributes.GetPropertyData(shadow);
if (propertyData is bool)
{
return (bool)propertyData;
}
else
{
return false;
}
}
// Set the value of the custom property.
set
{
this.DrawingAttributes.AddPropertyData(shadow, value);
}
}
void DrawingAttributes_PropertyDataChanged(object sender, PropertyDataChangedEventArgs e)
{
this.OnInvalidated(new EventArgs());
}
protected override void DrawCore(System.Windows.Media.DrawingContext context, DrawingAttributes overrides)
{
// create a drop shadow
//
if (this.Shadowed)
{
Geometry pathGeometry = this.GetGeometry(overrides).Clone();
pathGeometry.Transform = new TranslateTransform(5, 0);
try
{
context.PushOpacity(0.5);
context.DrawGeometry(Brushes.DarkGray, null, pathGeometry);
}
finally
{
context.Pop();
}
}
base.DrawCore(context, overrides);
}
}
Class ShadowedStroke
Inherits Stroke
Private shadow As New Guid("12345678-9012-3456-7890-123456789012")
Public Sub New(ByVal stylusPoints As StylusPointCollection, ByVal drawingAttributes As DrawingAttributes)
MyBase.New(stylusPoints, drawingAttributes)
AddHandler Me.DrawingAttributes.PropertyDataChanged, AddressOf DrawingAttributes_PropertyDataChanged
End Sub
Public Property Shadowed() As Boolean
' Return the value of the custom property, shadow.
' If there is no custom property, return false.
Get
If Not Me.DrawingAttributes.ContainsPropertyData(shadow) Then
Return False
End If
Dim propertyData As Object = Me.DrawingAttributes.GetPropertyData(shadow)
If TypeOf propertyData Is Boolean Then
Return CType(propertyData, Boolean)
Else
Return False
End If
End Get
' Set the value of the custom property.
Set
Me.DrawingAttributes.AddPropertyData(shadow, value)
End Set
End Property
Private Sub DrawingAttributes_PropertyDataChanged(ByVal sender As Object, ByVal e As PropertyDataChangedEventArgs)
Me.OnInvalidated(New EventArgs())
End Sub
Protected Overrides Sub DrawCore(ByVal context As System.Windows.Media.DrawingContext, _
ByVal overriddenAttributes As DrawingAttributes)
' create a drop shadow
'
If Me.Shadowed Then
Dim pathGeometry As Geometry = Me.GetGeometry(overriddenAttributes).Clone()
pathGeometry.Transform = New TranslateTransform(5, 0)
Try
context.PushOpacity(0.5)
context.DrawGeometry(Brushes.DarkGray, Nothing, pathGeometry)
Finally
context.Pop()
End Try
End If
MyBase.DrawCore(context, overriddenAttributes)
End Sub
End Class