How do I scroll a ScrollViewer in Design Time in Blend

blend, scrollviewer, wpf, xaml

Solution

Don't think there exists an out-of-the-box design-time attribute for this. However you can create one yourself quite easily.

say something like:

using System.ComponentModel;
using System.Windows;
using System.Windows.Controls;

public static class CustomDesignAttributes {
  private static bool? _isInDesignMode;

  public static DependencyProperty VerticalScrollToProperty = DependencyProperty.RegisterAttached(
    "VerticalScrollTo",
    typeof(double),
    typeof(CustomDesignAttributes),
    new PropertyMetadata(ScrollToChanged));

  public static DependencyProperty HorizontalScrollToProperty = DependencyProperty.RegisterAttached(
    "HorizontalScrollTo",
    typeof(double),
    typeof(CustomDesignAttributes),
    new PropertyMetadata(ScrollToChanged));

  private static bool IsInDesignMode {
    get {
      if (!_isInDesignMode.HasValue) {
        var prop = DesignerProperties.IsInDesignModeProperty;
        _isInDesignMode =
          (bool)DependencyPropertyDescriptor.FromProperty(prop, typeof(FrameworkElement)).Metadata.DefaultValue;
      }

      return _isInDesignMode.Value;
    }
  }

  public static void SetVerticalScrollTo(UIElement element, double value) {
    element.SetValue(VerticalScrollToProperty, value);
  }

  public static double GetVerticalScrollTo(UIElement element) {
    return (double)element.GetValue(VerticalScrollToProperty);
  }

  public static void SetHorizontalScrollTo(UIElement element, double value) {
    element.SetValue(HorizontalScrollToProperty, value);
  }

  public static double GetHorizontalTo(UIElement element) {
    return (double)element.GetValue(HorizontalScrollToProperty);
  }

  private static void ScrollToChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) {
    if (!IsInDesignMode)
      return;
    ScrollViewer viewer = d as ScrollViewer;
    if (viewer == null)
      return;
    if (e.Property == VerticalScrollToProperty) {
      viewer.ScrollToVerticalOffset((double)e.NewValue);
    } else if (e.Property == HorizontalScrollToProperty) {
      viewer.ScrollToHorizontalOffset((double)e.NewValue);
    }
  }
}

Now by setting the custom attached property in your xaml such as:

<ScrollViewer Height="200"
              local:CustomDesignAttributes.VerticalScrollTo="50">
...

In design time alone you should be able to view your design with a scroll offset like

while in actual run-time the control will be un-touched. The `CustomDesignAttributes` also has a similar property `local:CustomDesignAttributes.HorizontalScrollTo` for Horizontal offset at design-time.

Problem

Original source

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