Table of Contents

Dock Targets and Drop Indicators

Dock shows drop indicators using two controls: DockTarget (local docking) and GlobalDockTarget (global docking between windows). Both derive from DockTargetBase and are created by the docking pipeline during drag operations.

How targets are created

When a drag starts, DockControlState locates a control marked with DockProperties.IsDropArea. If that control is also marked with DockProperties.IsDockTarget, the docking pipeline creates a target adorner for it. The adorner is hosted either in the visual tree or inside a floating window, depending on DockSettings.UseFloatingDockAdorner.

Local targets are attached to the drop control (or DockProperties.DockAdornerHost if set). Global targets are attached to the nearest DockControl and display global docking options when they are available.

Global targets are only shown when the effective EnableGlobalDocking setting is true for the target dock. This property is inherited through the dock hierarchy, so disabling it on a parent dock disables global targets for the entire subtree.

Attached properties that drive targets

These DockProperties determine how targets behave:

Property Purpose
IsDockTarget Marks the control as a docking surface.
IsDropArea Marks the control as a valid drop surface.
ShowDockIndicatorOnly Hide the selector icons and show indicators only.
IndicatorDockOperation Assigns a DockOperation (Top/Bottom/Left/Right/Fill) to an indicator part.
DockAdornerHost Redirects the adorner to a specific host control.

Example of a drop surface that only shows indicators:

<Border DockProperties.IsDockTarget="True"
        DockProperties.ShowDockIndicatorOnly="True"
        DockProperties.DockAdornerHost="{Binding #Root}"
        Background="Transparent" />

DockTargetBase properties

DockTargetBase exposes properties used by the docking engine and styles:

  • ShowIndicatorsOnly toggles selector icons on or off.
  • ShowHorizontalTargets and ShowVerticalTargets enable or disable horizontal/vertical indicators.
  • IsGlobalDockAvailable and IsGlobalDockActive control pseudo classes used to style global docking state.

These values are set by the docking pipeline based on the current drag operation and the layout configuration. You typically customize their visuals in styles instead of setting them manually.

Styling targets

The default themes define template parts like PART_TopIndicator and PART_TopSelector. You can override them in a custom theme or add styles that react to pseudo classes:

<Style Selector="DockTarget:global-available">
  <Setter Property="Opacity" Value="1" />
</Style>

<Style Selector="DockTarget:global-active">
  <Setter Property="Opacity" Value="1" />
</Style>

To customize global targets, edit the GlobalDockTarget template. Its indicator panels use DockSettings.GlobalDockingProportion to size the split areas.

Adaptive global targets

IRootDock.EnableAdaptiveGlobalDockTargets reduces global docking indicators to only show options that change the layout. Enable it when you want to minimize drop choices in large dashboards:

rootDock.EnableAdaptiveGlobalDockTargets = true;

For an overview of all guides see the documentation index.

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