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Visual.TransformToDescendant Method

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

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

public GeneralTransform TransformToDescendant(
	Visual descendant
)

Parameters

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

ExceptionCondition
ArgumentNullException

descendant is null.

ArgumentException

The visual is not an ancestor of the descendant visual.

InvalidOperationException

The visual objects are not related.

The following markup example shows a TextBlock that is contained within a StackPanel object.


<StackPanel Name="myStackPanel" Margin="8">
  <TextBlock Name="myTextBlock" Margin="4" Text="Hello, world" />
</StackPanel>


The following code example shows how to use the TransformToDescendant method to retrieve the offset of the StackPanel relative to its child TextBlock. The offset values are contained within the returned GeneralTransform value.


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

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


The offset takes into account the Margin values for all objects. In this case, X is -4, and Y is -4. The offset values are negative values because the parent object is negatively offset relative to its child object.

.NET Framework

Supported in: 4, 3.5, 3.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

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

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