I have created a Canvas, and within it I placed a StackPanel. The StackPanel is horizontal, and it accepts a list of thumbnailed images. The Canvas has a fixed size. When I put more thumbnails than the Canvas width can hold, the StackPanel is supposed to overflow from the Canvas, so I can move it to center the current thumbnail.
Everything works correctly, only, the StackPanel's overflow is visible! Is there a way to hide it? Or is the entire approach wrong?
Here is a screenshot. The canvas is the red box. The stackpanel is blue semi-transparent.
http://www.netpalantir.it/static/sl_canvas_overflows.jpg
Thanks!
Since the Canvas has fixed size, you can use clipping. Basically you have to do:
<Canvas Width="400" Height="300">
<Canvas.Clip>
<RectangleGeometry Rect="0, 0, 400, 300"/>
</Canvas.Clip>
<!-- your StackPanel here -->
</Canvas>
Here are few useful posts on the topic:
Clipping in Silverlight
Cropping or Clipping in Silverlight
Related
I am trying to load an image within a canvas such that, if the size of image overflows the canvas, the scroll bars should get activated (MS Paint style)
<Window>
<ScrollViewer>
<Canvas ScrollViewer.HorizontalScrollBarVisibility="Visible"
ScrollViewer.VerticalScrollBarVisibility="Visible">
<Image Source="SampleImage.jpg" />
</Canvas>
</ScrollViewer>
</Window>
Now as Canvas is stretched to Window's size, scroll-bars won't appear as Canvas is not actually overflowing out of the Window.
Secondly, as the Image is much bigger than the Canvas, it is getting clipped at the bounds of Canvas, so ScrollViewer doesn't think that its content: Canvas is actually overflowing.
It happens a lot of time with StackPanels too, that even though the bound data has tens of rows, but still the scrollbars don't get activated. Sometimes scrollviewers appear as mystery to me.
So, what should be the basic logic kept in mind when using ScrollViewer control.
Thank you.
Edit: Just edited the question title, so that whosoever has problem with canvas can get this question easily in search.
From MSDN:
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.
Hovever, you can set Canvas Height and Width explicitely:
<ScrollViewer Height="100" Width="200">
<Canvas Height="400" Width="400">
//Content here
</Canvas>
</ScrollViewer>
Maybe one of these two Links might help you:
Silverlight Canvas on Scrollviewer not triggering
ScrollBars are not visible after changing positions of controls inside a Canvas
In my WP7 app, I have a user control, with a grid, and an ellipse in the layout root:
<Grid x:Name="LayoutRoot">
<Grid x:Name="grdCircle">
<Ellipse x:Name="elCircle" Stroke="#FFB91515" Margin="5"/>
</Grid>
</Grid>
I drop this on my main page in the WP7 app, and it looks fine in landscape mode, but when I switch to portrait the width expands and the height contracts, so it is no longer a circle. What I want is for the circle to be the max size it can be regardless of the orientation and still stay a circle.
I've tried putting SizeChanged event on LayoutRoot, and setting the grdCircle width/height to whatever was smaller - the LayoutRoot actual width or the LayoutRoot actual height, but as soon as I do that, changing the orientation doesn't fire the SizeChanged event of LayoutRoot anymore because LayoutRoot also becomes smaller. How can I ensure that my ellipse is always a circle and grows/shrinks based on the orientation?
Edit:
By default, the LayoutRoot grid should have horizontal and vertical alignment set to stretch with margins of 0, so shouldn't the LayoutRoot grid always grow to the size of its container?
Maybe you should take adventage of OrientationChanged event of a Page?
Updated
I think that your control is filling all space that is available. If you change orientation then the amount of space is changing - as a result your control is not a square any more. That fact implicates that the ellipse changes its shape from circle to ellipse, because your ellipse is also trying to fill in all available space. To avoid this you can set Stretch property of an ellipse to Uniform. This should resolve your problem.
How to let ItemsControl scroll vertically, if it's placed in a viewbox?
<Viewbox>
<ItemsControl ItemsSource="..." />
</Viewbox>
I need the Viewbox to scale all the content of my ItemsControl horizontally to the width of the phone (Viewbox does it perfectly, it scales the content in such a way that the widest row of ItemsControl occupies exactly the width, equal to the phone width). But now I cannot scroll the list vertically for some reason, I tried ScrollViewer, scrollbars of Viewbox, scrollbars of ItemsControl -- nothing works.
A ViewBox measures its contents, then transforms it so that it fits perfectly within the space available. This will remove the need for scrollbars!
Considering that phones have a fixed screen size, the ViewBox is often redundant. Why not just set an explicit size?
I have a sample app with a MultiScaleImageControl. By default it fills the available ViewPort width. How can i make it use the available height?
Edit (Copy from comment)
It's nothing more than
<Grid x:Name="LayoutRoot" Background="White">
<MultiScaleImage HorizontalAlignment="Left" Name="multiScaleImage1" VerticalAlignment="Top" />
</Grid>
My question doesn't aim at the width of the control itself, but at the displayed MultiScaleImage...
I would recommend that you remove the VerticalAlignment property. In fact get rid of the HorizontalAlignment as well. This lets the containing grid size the control for you.
You may also be seeing the control simply maintaining the aspect ratio of the image. If the image is wider than its high then at zoom level 1 the image will not fill the entire height.
How do I make a Canvas stretch fully horizontally with variable width? This is the parent Canvas, so it has no parents, only children.
XAML Source: it displays in blend
http://resopollution.com/xaml.txt
Use a Grid as the top level element in your UI - it'll stretch to fill its container. Then put a Canvas with HorizontalAlignment="Stretch" inside the Grid and it'll behave the way you want.
<Grid xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
<Canvas Background="Blue"/>
</Grid>
That worked for me. The key is your top level UI element. While a Grid fills all available space by default, Canvases take up only as much room as their contents demand.
I'm guessing you've tried
canvas.HorizontalAlignment = HorizontalAlignment.Stretch
If this doesn't work, then what you could do is bind the Width and Height properties of the canvas to the ActualWidth and ActualHeight properties of the containing window.
You could use a dock panel to get it to fill the available width. The last item in a dock panel list of controls is automatically stretched to fill the remaining space.
<DockPanel>
<Canvas />
</DockPanel>
The canvas should do this automatically, unless you are manually setting the height and/or width. What kind of control are you trying to place the canvas on? Can you post your code?
The problem is that you're specifying the Height and Width. Without these properties, the control may appear to vanish in the designer, but it should size appropriately when you insert the canvas into another control.
If I recall correctly, the next version of WPF will have 'DesignWidth' and 'DesignHeight' properties that allow you to show the control in the designer with a given size without effecting it's measurement when inserted into other controls.