WPF calculate Parent margin based on child control position

Question

I have following XAML. I have to set margin to CanvasRuler as per child control (LabelEditFrame) Left position. How do I do that.

   <wpfcommon:CanvasNavigationBar>
        <DockPanel>
            <wpfcommon:CanvasRuler />     <!-- Horizontal -->
            </wpfcommon:CanvasRuler  />   <!-- Vertical -->
            <border>
                <StackPanel>
                    <wpfcommon:LabelEditFrame>
                    </ wpfcommon:LabelEditFrame>
                </StackPanel>
            </border>
        </DockPanel>
    </wpfcommon:CanvasNavigationBar>

Right now I have this

enter image description here

I want to have this (I can do that by setting hard coded value, but I need to set it dynamically, so if position of child control gets changes, it will change ruler position automatically).

enter image description here

What would cause the user control to move like that? – CodingGorilla Jun 13 '12 at 15:05 — CodingGorilla, Jun 13 '12 at 15:05

score 0 · Answer 1 · answered Jun 13 '12 at 15:15

I suggest you to put all that stuff to Grid and allow it calculate anything for you:

<Grid>
    <Grid.RowDefinitions>
        <RowDefinition Height="SomeFixedHeightToGetTopMargin"/>
        <RowDefinition/>
    </Grid.RowDefinitions>
    <Grid.ColumnDefinitions>
        <ColumnDefinition  Width="SomeFixedWithToGetLeftMargin"/>
        <ColumnDefinition/>
    </Grid.ColumnDefinitions>

    <wpfcommon:CanvasRuler Grid.Column="1"/>
    <wpfcommon:CanvasRuler Grid.Row="1"/>
    <Border Grid.Row="1" Grid.Column="1">
        <StackPanel>
            <wpfcommon:LabelEditFrame/>
        </StackPanel>
    </Border>
</Grid>

score 0 · Accepted Answer · answered Jun 13 '12 at 15:18

From my experience, if this is on a Canvas and are children on a canvas, you can use the

Canvas.SetLeft

and

Canvas.SetTop

methods.

So for the Rulers, you can set the:

VerticalAlignment="Top", HorizontalAlignment="Left

Then when the LabelEditFrame is moved (whichever event you use to trigger that), you can adjust the two rulers with something like this:

Canvas.SetLeft(HorizontalCanvasRuler, LabelEditFrame.Margin.Left);
Canvas.SetTop(VerticalCanvasRuler, LabelEditFrame.Margin.Top);

I haven't tried this out, but I have used to adjust controls like this before so it should work :)

WPF calculate Parent margin based on child control position

2 Answers2