Assembly: PresentationFramework (in presentationframework.dll)
XML Namespace: http://schemas.microsoft.com/winfx/2006/xaml/presentation
Canvas is the only panel element that has no inherent layout characteristics. A Canvas has default Height and Width properties of zero, unless it is the child of an element that automatically sizes its child elements. Child elements of a Canvas are never resized, they are just positioned at their designated coordinates. This provides flexibility for situations in which inherent sizing constraints or alignment are not needed or wanted. For cases in which you want child content to be automatically resized and aligned, it is usually best to use a Grid element.
The ZIndex property determines the order in which child elements that share the same coordinate space appear. A higher ZIndex value for one child element indicates that this element will appear above another child element that has a lower value.
Child elements of a Canvas are always given the full size that they desire. As a result, vertical alignment and horizontal alignment have no effect inside a Canvas.
Canvas is a top-level layout control that you can use for absolute positioning of child content. For painting and drawing, you use Brushes and do not have to use a Canvas. For more information, see WPF Brushes Overview.
By default, panel elements do not receive focus. To compel a panel element to receive focus, set the Focusable property to true.
This example shows how to create and use an instance of Canvas.
When you use Extensible Application Markup Language (XAML) to position TextBlock elements, use the Top and Left properties.
WindowTitle = "Canvas Sample" 'Create a Canvas as the root Panel Dim myCanvas As New Canvas() myCanvas.Background = Brushes.LightSteelBlue Dim txt1 As New TextBlock txt1.FontSize = 14 txt1.Text = "Hello World!" Canvas.SetLeft(txt1, 10) Canvas.SetTop(txt1, 100) myCanvas.Children.Add(txt1) 'Add a second text element to show how absolute positioning works in a Canvas Dim txt2 As New TextBlock txt2.FontSize = 22 txt2.Text = "Isn't absolute positioning handy?" Canvas.SetLeft(txt2, 75) Canvas.SetTop(txt2, 200) myCanvas.Children.Add(txt2) Me.Content = myCanvas
<Page WindowTitle="Canvas Sample" xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"> <Canvas Background="LightSteelBlue"> <TextBlock FontSize="14" Canvas.Top="100" Canvas.Left="10">Hello World!</TextBlock> <TextBlock FontSize="22" Canvas.Top="200" Canvas.Left="75">Isn't absolute positioning handy?</TextBlock> </Canvas> </Page>
|How to: Wrap a Border Around the Content of a Canvas|| |
This example shows how to wrap a Canvas element with a Border.
|How to: Absolutely Position Elements in a Canvas|| |
This example shows how to use the Canvas control to absolutely position content.
Windows 98, Windows Server 2000 SP4, Windows CE, Windows Millennium Edition, Windows Mobile for Pocket PC, Windows Mobile for Smartphone, Windows Server 2003, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP SP2, Windows XP Starter EditionThe Microsoft .NET Framework 3.0 is supported on Windows Vista, Microsoft Windows XP SP2, and Windows Server 2003 SP1.