แก้ไข

แชร์ผ่าน

Visual.TransformToAncestor Method

  • Reference

Definition

Namespace:
System.Windows.Media
Assembly:
PresentationCore.dll

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

Overloads

TransformToAncestor(Visual3D)

Returns a transform that can be used to transform coordinates from the Visual to the specified Visual3D ancestor of the visual object.
TransformToAncestor(Visual)

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

TransformToAncestor(Visual3D)

Returns a transform that can be used to transform coordinates from the Visual to the specified Visual3D ancestor of the visual object.

public:
 System::Windows::Media::Media3D::GeneralTransform2DTo3D ^ TransformToAncestor(System::Windows::Media::Media3D::Visual3D ^ ancestor);
public System.Windows.Media.Media3D.GeneralTransform2DTo3D TransformToAncestor (System.Windows.Media.Media3D.Visual3D ancestor);
member this.TransformToAncestor : System.Windows.Media.Media3D.Visual3D -> System.Windows.Media.Media3D.GeneralTransform2DTo3D
Public Function TransformToAncestor (ancestor As Visual3D) As GeneralTransform2DTo3D

Parameters

ancestor
Visual3D

The Visual3D to which the coordinates are transformed.

Returns

GeneralTransform2DTo3D

A transform that can be used to transform coordinates from the Visual to the specified Visual3D ancestor of the visual object.

Applies to

TransformToAncestor(Visual)

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

public:
 System::Windows::Media::GeneralTransform ^ TransformToAncestor(System::Windows::Media::Visual ^ ancestor);
public System.Windows.Media.GeneralTransform TransformToAncestor (System.Windows.Media.Visual ancestor);
member this.TransformToAncestor : System.Windows.Media.Visual -> System.Windows.Media.GeneralTransform
Public Function TransformToAncestor (ancestor As Visual) As GeneralTransform

Parameters

ancestor
Visual

The Visual to which the coordinates are transformed.

Returns

GeneralTransform

A value of type GeneralTransform.

Exceptions

ArgumentNullException

ancestor is null.

ArgumentException

ancestor is not an ancestor of the visual.

InvalidOperationException

The visual objects are not related.

Examples

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

<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.

// 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));

' Return the general transform for the specified visual object.
Dim generalTransform1 As GeneralTransform = myTextBlock.TransformToAncestor(Me)

' Retrieve the point value relative to the parent.
Dim currentPoint As Point = 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.

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.

// 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);

' Return the offset vector for the TextBlock object.
Dim vector As Vector = VisualTreeHelper.GetOffset(myTextBlock)

' Convert the vector to a point value.
Dim currentPoint As New Point(vector.X, vector.Y)

Applies to