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如何:取得唯讀 Freezable 的可寫入複本

此範例示範如何使用 Clone 方法來建立唯讀 Freezable 的可寫入複本。

Freezable 物件標示為唯讀 (「凍結」) 後,您無法修改它。 不過,您可以使用 Clone 方法來建立凍結物件的可修改複製品。

範例

下列範例會建立凍結 SolidColorBrush 物件的可修改複製品。

Button myButton = new Button();
SolidColorBrush myBrush = new SolidColorBrush(Colors.Yellow);

// Freezing a Freezable before it provides
// performance improvements if you don't
// intend on modifying it.
if (myBrush.CanFreeze)
{
    // Makes the brush unmodifiable.
    myBrush.Freeze();
}

myButton.Background = myBrush;

// If you need to modify a frozen brush,
// the Clone method can be used to
// create a modifiable copy.
SolidColorBrush myBrushClone = myBrush.Clone();

// Changing myBrushClone does not change
// the color of myButton, because its
// background is still set by myBrush.
myBrushClone.Color = Colors.Red;

// Replacing myBrush with myBrushClone
// makes the button change to red.
myButton.Background = myBrushClone;
Dim myButton As New Button()
Dim myBrush As New SolidColorBrush(Colors.Yellow)

' Freezing a Freezable before it provides
' performance improvements if you don't
' intend on modifying it. 
If myBrush.CanFreeze Then
    ' Makes the brush unmodifiable.
    myBrush.Freeze()
End If


myButton.Background = myBrush

' If you need to modify a frozen brush,
' the Clone method can be used to
' create a modifiable copy.
Dim myBrushClone As SolidColorBrush = myBrush.Clone()

' Changing myBrushClone does not change
' the color of myButton, because its
' background is still set by myBrush.
myBrushClone.Color = Colors.Red

' Replacing myBrush with myBrushClone
' makes the button change to red.
myButton.Background = myBrushClone

如需有關 Freezable 物件詳細資訊,請參閱 Freezable 物件概觀

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