如何:建立自訂面板項目
範例
此範例示範如何覆寫 專案的預設版面配置行為 Panel ,並建立衍生自 Panel 的自訂版面設定項目。
此範例會定義稱為 PlotPanel
的簡單自訂 Panel 專案,它會根據兩個硬式編碼的 x 和 y 座標來放置子專案。 在此範例中, x
和 y
都設定為 50
;因此,所有子專案都位於 x 和 y 軸上的該位置。
為了實作自訂 Panel 行為,此範例會使用 MeasureOverride 和 ArrangeOverride 方法。 每個方法都會傳 Size 回定位和轉譯子專案所需的資料。
public:
ref class PlotPanel : Panel {
public:
PlotPanel () {};
protected:
// Override the default Measure method of Panel
virtual Size MeasureOverride(Size availableSize) override
{
Size^ panelDesiredSize = gcnew Size();
// In our example, we just have one child.
// Report that our panel requires just the size of its only child.
for each (UIElement^ child in InternalChildren)
{
child->Measure(availableSize);
panelDesiredSize = child->DesiredSize;
}
return *panelDesiredSize ;
}
protected:
virtual System::Windows::Size ArrangeOverride (Size finalSize) override
{
for each (UIElement^ child in InternalChildren)
{
double x = 50;
double y = 50;
child->Arrange(Rect(Point(x, y), child->DesiredSize));
}
return finalSize;
};
};
public class PlotPanel : Panel
{
// Default public constructor
public PlotPanel()
: base()
{
}
// Override the default Measure method of Panel
protected override Size MeasureOverride(Size availableSize)
{
Size panelDesiredSize = new Size();
// In our example, we just have one child.
// Report that our panel requires just the size of its only child.
foreach (UIElement child in InternalChildren)
{
child.Measure(availableSize);
panelDesiredSize = child.DesiredSize;
}
return panelDesiredSize ;
}
protected override Size ArrangeOverride(Size finalSize)
{
foreach (UIElement child in InternalChildren)
{
double x = 50;
double y = 50;
child.Arrange(new Rect(new Point(x, y), child.DesiredSize));
}
return finalSize; // Returns the final Arranged size
}
}
Public Class PlotPanel
Inherits Panel
'Override the default Measure method of Panel.
Protected Overrides Function MeasureOverride(ByVal availableSize As System.Windows.Size) As System.Windows.Size
Dim panelDesiredSize As Size = New Size()
' In our example, we just have one child.
' Report that our panel requires just the size of its only child.
For Each child As UIElement In InternalChildren
child.Measure(availableSize)
panelDesiredSize = child.DesiredSize
Next
Return panelDesiredSize
End Function
Protected Overrides Function ArrangeOverride(ByVal finalSize As System.Windows.Size) As System.Windows.Size
For Each child As UIElement In InternalChildren
Dim x As Double = 50
Dim y As Double = 50
child.Arrange(New Rect(New System.Windows.Point(x, y), child.DesiredSize))
Next
Return finalSize
End Function
End Class
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