TransformToDescendant Method

Visual.TransformToDescendant Method (Visual)


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


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.

Exception Condition

descendant is null.


The visual is not an ancestor of the descendant visual.


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" />

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
Available since 3.0
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