Dock

Dock Properties in Control Templates

DockProperties is a set of attached properties provided by the Dock.Settings package. They expose metadata used by the drag and drop engine to detect where docking interactions can start and where dockables can be dropped. The default themes apply these properties so the layout system can find the correct visuals during a drag operation.

Why are DockProperties required?

When a user drags a document or tool the DockControl walks up the visual tree to locate elements marked as drop areas or drag handles. Without these markers the engine cannot determine valid targets and dragging will not behave correctly. The built‑in styles set these properties on specific elements (for example tab headers or layout panels) but custom templates must do the same.

The available properties are:

Property	Type	Purpose
IsDockTarget	bool	Marks a control as a surface that can show a dock adorner and accept drops.
IsDragArea	bool	Identifies an element that can initiate a drag when pressed.
IsDropArea	bool	Identifies an element that can accept dropped dockables.
IsDragEnabled	bool	Enables or disables dragging of dockables contained within the control.
IsDropEnabled	bool	Enables or disables dropping of dockables onto the control.

Using the properties in control themes

Every control template that participates in docking should set the appropriate DockProperties. The default themes include them on tab strips, pinned panels and window chrome. When creating a custom template copy these setters so dragging continues to work:

<Style Selector="{x:Type DocumentTabStrip}">
    <Setter Property="(DockProperties.IsDragEnabled)" Value="{Binding CanDrag}" />
    <Setter Property="(DockProperties.IsDropEnabled)" Value="{Binding CanDrop}" />
</Style>

<!-- Parts of the template that accept drops -->
<Border x:Name="PART_BorderFill"
        DockProperties.IsDropArea="True" />

Without the attached properties above the drag logic would not detect the border as a valid drop area and documents could not be rearranged.

Setting DockProperties in code

The properties can be accessed through static getter and setter methods. They are normal Avalonia attached properties, so you may modify them at runtime if needed:

// Disable dropping onto a specific control
DockProperties.SetIsDropEnabled(myControl, false);

// Query whether a control is marked as a drag handle
bool isDragArea = DockProperties.GetIsDragArea(myBorder);

These helpers are useful when toggling behaviour dynamically, for example to disable drag operations while a modal dialog is shown.

For global drag and drop settings see the Dock settings guide which demonstrates how the same properties can be attached at the window level.

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