How to draw scrollbars on WPF Canvas - wpf

Question

I am trying to create a canvas with scroll bars.
Can anyone help me give some ideas on how to do this?
I have already tried using grid of 1 row and 1 column but due to certain constraints I want to use canvas.
Thanks in advance!

Answer 1

You could put the canvas inside of a scrollviewer. I tried this quick test and it allowed me to scroll through the contents of the canvas.
<ScrollViewer Height="100" Width="200">
<Canvas Height="400" Width="400">
//Content here
</Canvas>
</ScrollViewer>
edit: Here is an example where the scroll-bars show up only when needed, and it changes dynamically as the canvas size changes.
<Button Content="Change Canvas Size" Click="ChangeCanvasSize_Click"/>
<ScrollViewer Height="100" Width="200" VerticalScrollBarVisibility="Auto" HorizontalScrollBarVisibility="Auto">
<Canvas x:Name="TestCanvas">
<TextBlock Text="Test Test"/>
</Canvas>
</ScrollViewer>
Changing canvas size with button click:
private void ChangeCanvasSize_Click(object sender, RoutedEventArgs e)
{
TestCanvas.Width = 600;
TestCanvas.Height = 600;
}
In this example, I start out with no scroll-bars and when I click the button to expand the canvas, scroll-bars appear.

Answer 2

Ok after working with it for sometime I figured out a way. Create a XAML like this
<ScrollViewer>
<Grid x:Name="drawingGrid" SizeChanged="drawingGrid_SizeChanged">
<Canvas Name="drawingCanvas"> /<Canvas>
</Grid>
</ScrollViewer>
On windowLoad function set the canvas height/width equal to grid height/width. Update the canvas ht/wd:
when grid size changes, due to mininmize/maximize.
dragging an element beyond the boundaries of canvas or creating a new element too close the edge of canvas
double dHeight = 220;
if (drawingCanvas.Height < CurrentPosition.Y + dHeight)
{
// increase canvas height
drawingCanvas.Height += (2 * dHeight);
}
Hope this is of some help. Please share if anyone has any better idea or suggestions to improve this.

Answer 3

By combining Mario-sannum's answer and your question then I've made a solution that should work fine in most cases..
<ScrollViewer>
<Grid x:Name="drawingGrid" SizeChanged="drawingGrid_SizeChanged">
<Canvas Name="c">
<TextBlock x:Name="draw_Text" Text="Test Test"/>
</<Canvas>
</Grid>
</ScrollViewer>
void drawingGrid_SizeChanged(object sender, SizeChangedEventArgs e)
{
try { c.Height = draw_Text.ActualHeight; } catch { }
try { c.Width = draw_Text.ActualWidth; } catch { }
}
That should resize the Canvas so the scrollviewer can scroll...