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Event handler signalled prior to expanding a node on the tree view control.
Source position: comctrls.pp line 3661
protected property TCustomTreeView.OnExpanding : TTVExpandingEvent |
OnExpanding is a TTVExpandingEvent property with the event handler signalled before a tree node is expanded on the tree view control. It is signalled (when assigned) from the CanExpand method, and allows the application to perform actions needed before the tree node is expanded to reveal its child nodes.
Arguments for the event handler include:
OnExpanding is not signalled if the tree node does not have any child nodes (HasChildren is False).
Use OnExpanded to perform actions needed after a tree node has been expanded on the control.
Use OnCollapsing and OnCollapsed to perform actions before or after a node is collapsed on the tree view control.
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True if the specified tree node can be expanded. |
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Determines if the specified tree node has child nodes. |
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Event handler signalled when a node on the tree view control has been expanded. |
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Event handler signalled prior to collapsing a node on the tree view control. |
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Event handler signalled when a tree node has been collapsed on the control. |
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TTVExpandingEvent - generic event handling method for expanding a tree node if AllowExpansion is True. |
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True if the node has been expanded, False when collapsed. |
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True if the tree node is visible in the associated TreeView control. |
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Indicates whether the tree node has child nodes. |
| Version 3.2 | Generated 2024-02-25 | Home |