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?
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.
I'm having a problem where I have elements such as Listboxes and Rich Text boxes that I want to set to size automatically in xaml according to the size of the window, but I only want it to resize to the size of the window and then put scrollbars if the content is any bigger than that.
Unfortunately, the only way I can get scroll bars to work is if I set a specific height of the listbox/rich text box (which does not work because I want it to automatically resize to the height of the grid that it is contained within, which is generally the height of the window (auto).
Any help would be greatly appreciated.
You do not need to use fixed values for Width and Height - you should rather specify a minimum width/height for your controls using the MinWidth and MinHeight properties. Then try a layout similar to this:
<Window>
<ScrollViewer HorizontalScrollBarVisibility="Auto" VerticalScrollBarVisibility="Auto">
<Grid>
<ListBox MinWidth="500" MinHeight="250"/>
<!-- any other controls... -->
</Grid>
</ScrollViewer>
</Window>
The Grid generally uses all the space it gets if its alignment properties are set to Stretch and if at least one row/column is set to be star-sized. In this case, there are only one row and one column, implicitly created, both star-sized by default.
To make the ScrollViewer work, you need to somehow set a minimum size of your content controls because otherwise the ScrollViewer does not know when to activate the ScrollBars. In the example above, I have done that using the MinHeight and MinWidth properties of the ListBox, but you could also set these properties on the Grid's RowDefinitions and/or ColumnDefinitions.
Now, if you resize the window, so that the Width becomes smaller than 500, you will see that scrollbars will appear. Just check it out.
When I place a Datagrid in a WPF Grid Layout container, the datagrid lengthens the Grid Layout.
I want it to occupy only the space available on screen.
Make sure your Grid.ColumnDefinition or Grid.RowDefinition's Width or Height is not set to Auto. If you set it to a fixed size or a star size then the row/column should not resize.
If you're still having problems a code sample would be useful.
You should place your Datagrid into a ScrollViewer, and the ScrollViewer into your Grid cell.
the grid is placed inside a tabitem.
I tried the scrollviewer. but the only thing that happens:
the scrollviewer gets as large as the too long datagrid.
as the tabitem can vary in height, I would rather not like to specify a fixed height for the grid.
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.