How To Find ScrollViewer Inside of WPF ContentControl? - wpf

Question

WPF 4.5 / C#
I've got an app where I have several WPF Windows each utilizing this custom content control. I use it in the XAML like this:
<ContentControl Name="myControl" Style="{StaticResource ReservedSpaceScrollBar}"
In the code behind, I need to be able to access the ScrollViewer inside, so I can call .ScrollToTop()
I've tried this, but it doesn't work:
((ScrollViewer)this.myControl.FindName("Scroll")).ScrollToTop();
...but .FindName doesn't find the ScrollViewer. What am I doing wrong? How make this work?
The XAML for the Style is below...
<Style TargetType="{x:Type ContentControl}" x:Key="ReservedSpaceScrollBar">
<Setter Property="FocusVisualStyle" Value="{x:Null}"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="{x:Type ContentControl}">
<ScrollViewer PanningMode="Both" VerticalScrollBarVisibility="Auto" x:Name="Scroll" FocusVisualStyle="{x:Null}">
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<ContentPresenter />
<Border Width="{x:Static SystemParameters.VerticalScrollBarWidth}" x:Name="Placeholder" Grid.Column="1" />
</Grid>
</ScrollViewer>
<ControlTemplate.Triggers>
<DataTrigger Binding="{Binding ComputedVerticalScrollBarVisibility, ElementName=Scroll}" Value="Visible">
<Setter TargetName="Placeholder" Property="Visibility" Value="Collapsed" />
</DataTrigger>
</ControlTemplate.Triggers>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>

Answer 1

Look into the VisualTreeHelper
Using that class you can look into children of elements; for example:
var childCount = VisualTreeHelper.GetChildrenCount(this.myControl);
for (int i = 0; i < childCount; i++)
{
var child = VisualTreeHelper.GetChild(this.myControl, i);
if (child.GetValue(NameProperty).ToString() == "Scroll")
{
((ScrollViewer)child).ScrollToTop();
}
}