I'm trying to implement panning within a Canvas within a scrollviewer like:
<ScrollViewer>
<Canvas>
<!-- some visual elements here -->
</Canvas>
</ScrollViewer>
I want a click and drag operation within the canvas to cause the contents of the canvas to move. I've tried handling the MouseDown, MouseMove, and MouseUp events to do a translation in the manner described here but it hasn't worked.
Any ideas?
You can't do that with your current setup. A Canvas will stretch beyond its parent container and the scrollviewer won't know the size of the Canvas (it will tell it it doesn't need to scroll) and therefore can't create the handles.
If you want to skip with that set up change the canvas to a grid and use the Vertical Scroll and Horizontal Scroll and associated set properties to move the visible section of the grid around.
Try giving your Canvas a set Width and Height and give it a background color (Transparent should be fine) and see if that helps you get your mouse events.
Related
I have two controls on my form, i have two use case
When i drag from the right corner, i want to re size the form and all controls should be aligned appropriately
When i drag from the right edge, the right side controls should be hidden
I have already tried the Res size mode as can re size and i can handle the first user scenario.
I have used a View Box property which is enabling the re size of window when i drag and shrink it.
I am not able to find a control that can allow me to re size and hide a portion of the window at two different events
Some ideas for you.
You may handle the SizeChanged event for your window.
SizeChangedEventArgs has two propertis: HeightChanged, WidthChanged.
Maybe you can collapse the viewbox when only Widthchanged is ture.
Update:
After tested, Collapse viewbox will collapse the content in viewbox. So I write code like below to avoid this issue. But It's worked not very well. Just FYI:
<Grid>
<Viewbox>
<content/>
</Viewbox>
<content/>
</Grid>
I have certain rectangular usercontrols. How can I place it at a certain x-y coordinate in the canvas? Once I place a user control, I need to evaluate the position to place the next control based on the rendered width/height of the previously placed control. How to do these correctly in Silverlight.
To position controls inside a canvas panel, you use the Canvas class's attached properties, Canvas.Left and Canvas.Top. So, if you wanted your control to be positioned at 100,20 (relative to the top-left corner of the canvas), you would enter:
<Canvas>
<Rectangle Canvas.Left="100" Canvas.Top="20"/>
</Canvas>
Alternatively, you could use this in the code-behind:
yourControl.SetValue(Canvas.LeftProperty,100.0);
yourControl.SetValue(Canvas.TopProperty,20.0);
If you've got several controls you're trying to arrange dynamically though, you may want to consider using a StackPanel or Grid intead of a Canvas.
In my Silverlight 4 application I need to create a user control with an irregular shape. The "main display" of the UC is a standard rectangle but I need to have tabs (simple text blocks, where the user can click) that are outside of the main display rectangle.
Is this possible with Silverlight 4? If so, how?
Thanks in advance.
You can position elements of a control outside its normal layout in a number of ways. You could use Canvas but if most of the control is standard Grid rectangle then you can use a Grid. The trick is to use negative Margins.
<Grid x:Name="LayoutRoot">
<Border Margin="0 -22 0 0">
<TextBlock Text="I appear above the UserControl layout" />
</Border>
</Grid>
Note that if the Usercontrol is being used as the Visual root then this won't work because the Silverlight plugin will not render beyound its client rectangle.
It is, you can have transparent background behind the tabs which can let clicks through, effectively behaving as if the shape was different. The UserControl will still have a rectangular shape including the tabs, unless you wrap then into a Popup and float out of the UC with some offset.
Technically, you can have elements outside the UserControl's rectangle if you use a Canvas for your LayoutRoot instead of a Grid. Elements in a Canvas aren't clipped to the canvas size. I wouldn't recommend this, however, because you won't be able to use Margin to size and align your controls inside it. It would be better to have all child controls inside a Grid LayoutRoot.
Which brings us to the question of irregularity. If you want to 'see through' parts of the control and be able to click through them (i.e. click objects underneath it), all you need to do is keep the UserControl's and the LayoutRoot's Background to null or just not set it at all. Wherever there is a lack of any background, clicks will go through. Note that if you set the background to Transparent it will make the control behave as a rectangle (as if it's filled with solid color) with respect to mouse input.
Another thing is if you want to see HTML controls under the see-through parts of your app. Then, you'll have to use windowless mode, but that's another can of worms.
I have an ItemsControl in a ScrollViewer. The items in the ItemsControl are expanded to a DataTemplate which basically consists of an Adorner.
Now the problem is, when scrolling, the Visual Children of the Adorner are visible outside the ScrollViewer. Lets say I scroll from the Horizontal Offset 0 to 100, the Visual Children of the Adorner move to the left and are visible next to the ScrollViewer, although they should be hidden. Setting ClipToBounds on the ItemsControl or the ScrollViewer does not work.
I understand, that Adorner are rendered above all elements z-order wise, but they really shouldn't be visible in such cases as with the ScrollViewer. The adorned Element by the way behaves like expected and is not visible through the ScrollViewer.
Is there any easy way to "clip" the Adorners, so that they are only visible in the visible scroll area?
Thanks,
Andrej
Setting ClipToBounds on the containing control is not enough. You must set the adorner's IsClipEnabled property too.
I've encountered the same problem when subclassing the WPFToolkit DataGrid to draw an adorner around the current cell.
The content of the ScrollViewer is rendered by a ScrollContentPresenter instance. ScrollContentPresenter has its own adorner layer, which is accessible through the ScrollContentPresenter.AdornerLayer property.
I found that my adorner correctly clips if I add it to that layer.
My solution was to push a clip region onto the drawing context, render whatever I needed, and pop the clipping at the end, like this:
drawingContext.PushClip(new RectangleGeometry(new Rect(0, 0, this.AdornedElement.RenderSize.Width, this.AdornedElement.RenderSize.Height)));
// continue drawing
drawingContext.Pop();
You can plug this in into any Adorner, the bounds are already available as part of the element.
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.