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title, ms.date, dev_langs, helpviewer_keywords, ms.assetid
| title | ms.date | dev_langs | helpviewer_keywords | ms.assetid | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| How to: Get the Offset of a Visual | 03/30/2017 |
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889a1dd6-1b11-445a-b351-fbb04c53ee34 |
How to: Get the Offset of a Visual
These examples show how to retrieve the offset value of a visual object that is relative to its parent, or any ancestor or descendant.
Example
The following markup example shows a xref:System.Windows.Controls.TextBlock that is defined with xref:System.Windows.FrameworkElement.Margin%2A value of 4.
[!code-xamlVisualSnippets#VisualSnippet1]
The following code example shows how to use the xref:System.Windows.Media.VisualTreeHelper.GetOffset%2A method to retrieve the offset of the xref:System.Windows.Controls.TextBlock. The offset values are contained within the returned xref:System.Windows.Vector value.
[!code-csharpVisualSnippets#VisualSnippet2] [!code-vbVisualSnippets#VisualSnippet2]
The offset takes into account the xref:System.Windows.FrameworkElement.Margin%2A value. In this case, xref:System.Windows.Vector.X%2A is 4, and xref:System.Windows.Vector.Y%2A is 4.
The returned offset value is relative to the parent of the xref:System.Windows.Media.Visual. If you want to return an offset value that is not relative to the parent of a xref:System.Windows.Media.Visual, use the xref:System.Windows.Media.Visual.TransformToAncestor%2A method.
Getting the Offset Relative to an Ancestor
The following markup example shows a xref:System.Windows.Controls.TextBlock that is nested within two xref:System.Windows.Controls.StackPanel objects.
[!code-xamlVisualSnippets#VisualSnippet7]
The following illustration shows the results of the markup.
TextBlock nested within two StackPanels
The following code example shows how to use the xref:System.Windows.Media.Visual.TransformToAncestor%2A method to retrieve the offset of the xref:System.Windows.Controls.TextBlock relative to the containing xref:System.Windows.Window. The offset values are contained within the returned xref:System.Windows.Media.GeneralTransform value.
[!code-csharpVisualSnippets#VisualSnippet5] [!code-vbVisualSnippets#VisualSnippet5]
The offset takes into account the xref:System.Windows.FrameworkElement.Margin%2A values for all objects within the containing xref:System.Windows.Window. In this case, xref:System.Windows.Vector.X%2A is 28 (16 + 8 + 4), and xref:System.Windows.Vector.Y%2A is 28.
The returned offset value is relative to the ancestor of the xref:System.Windows.Media.Visual. If you want to return an offset value that is relative to the descendant of a xref:System.Windows.Media.Visual, use the xref:System.Windows.Media.Visual.TransformToDescendant%2A method.
Getting the Offset Relative to a Descendant
The following markup example shows a xref:System.Windows.Controls.TextBlock that is contained within a xref:System.Windows.Controls.StackPanel object.
[!code-xamlVisualSnippets#VisualSnippet4]
The following code example shows how to use the xref:System.Windows.Media.Visual.TransformToDescendant%2A method to retrieve the offset of the xref:System.Windows.Controls.StackPanel relative to its child xref:System.Windows.Controls.TextBlock. The offset values are contained within the returned xref:System.Windows.Media.GeneralTransform value.
[!code-csharpVisualSnippets#VisualSnippet9] [!code-vbVisualSnippets#VisualSnippet9]
The offset takes into account the xref:System.Windows.FrameworkElement.Margin%2A values for all objects. In this case, xref:System.Windows.Vector.X%2A is -4, and xref:System.Windows.Vector.Y%2A is -4. The offset values are negative values, since the parent object is negatively offset relative to its child object.