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如何：決定 Freezable 是否凍結

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此範例會顯示如何確定 Freezable 物件是否已凍結。 如果您嘗試修改已凍結的 Freezable 物件，則會擲回 InvalidOperationException。 若要避免擲回此例外狀況，請使用 IsFrozen 物件的 Freezable 屬性來確定它是否已凍結。

範例

下列範例會凍結 SolidColorBrush，然後使用 IsFrozen 屬性來確定它是否已凍結，以測試它。


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

if (myBrush.CanFreeze)
{
    // Makes the brush unmodifiable.
    myBrush.Freeze();
}

myButton.Background = myBrush;

if (myBrush.IsFrozen) // Evaluates to true.
{
    // If the brush is frozen, create a clone and
    // modify the clone.
    SolidColorBrush myBrushClone = myBrush.Clone();
    myBrushClone.Color = Colors.Red;
    myButton.Background = myBrushClone;
}
else
{
    // If the brush is not frozen,
    // it can be modified directly.
    myBrush.Color = Colors.Red;
}



Dim myButton As New Button()
Dim myBrush As New SolidColorBrush(Colors.Yellow)

If myBrush.CanFreeze Then
    ' Makes the brush unmodifiable.
    myBrush.Freeze()
End If

myButton.Background = myBrush


If myBrush.IsFrozen Then ' Evaluates to true.
    ' If the brush is frozen, create a clone and
    ' modify the clone.
    Dim myBrushClone As SolidColorBrush = myBrush.Clone()
    myBrushClone.Color = Colors.Red
    myButton.Background = myBrushClone
Else
    ' If the brush is not frozen,
    ' it can be modified directly.
    myBrush.Color = Colors.Red
End If

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

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