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Visual.TransformToAncestor Method (Visual)

.NET Framework 3.5

Returns a transform that can be used to transform coordinates from the Visual to the specified Visual ancestor of the visual object.

Namespace: System.Windows.Media
Assembly: PresentationCore (in PresentationCore.dll)

Syntax

C++

JScript

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public GeneralTransform TransformToAncestor(
	Visual ancestor
)

XAML

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You cannot use methods in XAML.

Parameters

ancestor: Type: System.Windows.Media.Visual
The Visual to which the coordinates are transformed.

Return Value

Type: System.Windows.Media.GeneralTransform
A value of type GeneralTransform.

Exceptions

Exception	Condition
ArgumentNullException	ancestor is null.
ArgumentException	ancestor is not an ancestor of the visual.
InvalidOperationException	The visual objects are not related.

Remarks

Alternatively, you can use the VisualTreeHelper.GetOffset method to retrieve the offset of a visual object relative to its parent. The offset values are contained within the returned Vector value.

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// Return the offset vector for the TextBlock object.
Vector vector = VisualTreeHelper.GetOffset(myTextBlock);

// Convert the vector to a point value.
Point currentPoint = new Point(vector.X, vector.Y);

Examples

The following markup example shows a TextBlock that is nested within two StackPanel objects.

XAML

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<Window xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" >
  <StackPanel Margin="16">
    <StackPanel Margin="8">
      <TextBlock Name="myTextBlock" Margin="4" Text="Hello, world" />
    </StackPanel>
  </StackPanel>
</Window>

The following code example shows how to use the TransformToAncestor method to retrieve the offset of the TextBlock relative to the containing Window. The offset values are contained in the returned GeneralTransform.

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// Return the general transform for the specified visual object.
GeneralTransform generalTransform1 = myTextBlock.TransformToAncestor(this);

// Retrieve the point value relative to the parent.
Point currentPoint = generalTransform1.Transform(new Point(0, 0));

The offset takes into account the Margin values for all objects within the containing Window. In this case, X is 28, and Y is 28.

Platforms

Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

Version Information

.NET Framework

Supported in: 3.5, 3.0

Reference

Visual Class

Visual Members

TransformToAncestor Overload

System.Windows.Media Namespace

Other Resources

How to: Get the Offset of a Visual

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