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Docs: LCL/comctrls. Updates content in TCustomTreeview topics, including:
* TCustomTreeView.OnEditingEnd * TCustomTreeView.OnExpanded * TCustomTreeView.OnExpanding * TCustomTreeView.OnGetImageIndex * TCustomTreeView.OnGetSelectedIndex * TCustomTreeView.OnHasChildren * TCustomTreeView.ShowButtons
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@ -33931,7 +33931,7 @@ Event handler signalled when EndEditing is called for the control.
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event handler signalled when the node editor for the tree view control is
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deactivated or reset. It is signalled (when assigned) from the EndEditing
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method, which occurs during node selection or scrolling and when a tree node
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calls its EndEditing method.
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calls its EndEdit method.
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</p>
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<p>
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Arguments to the event handler include:
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@ -33965,7 +33965,7 @@ action or the node editor reset.
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</descr>
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<seealso>
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<link id="TCustomTreeView.EndEditing"/>
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<link id="TTreeNode.EndEditing"/>
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<link id="TTreeNode.EndEdit"/>
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<link id="TTVEditingEndEvent"/>
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</seealso>
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</element>
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@ -33975,9 +33975,58 @@ action or the node editor reset.
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Event handler signalled when a node on the tree view control has been expanded.
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</short>
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<descr>
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<!-- WIP: Here -->
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<p>
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<var>OnExpanded</var> is a <var>TTVExpandedEvent</var> property with the event
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handler signalled when a node on the tree view control has been expanded. It
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is signalled (when assigned) from the Expand method, and occurs after child
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nodes have been displayed and scroll bars for the control have been updated.
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Values in the States property have already been updated to indicate that a
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node has been expanded and that visible items need to be updated.
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</p>
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<p>
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An application can implement a handler routine to perform actions needed when
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the tree node or its children become visible on the control.
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</p>
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<p>
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Arguments for the event handler include:
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</p>
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<dl>
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<dt>
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Sender
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</dt>
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<dd>
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The object instance (TCustomTreeView) for the event.
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</dd>
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<dt>
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Node
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</dt>
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<dd>
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The TTreeNode instance with the node expanded on the tree view control.
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</dd>
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</dl>
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<p>
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Use OnExpanding to perform actions needed immediately prior to expanding a
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node on the tree view control.
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</p>
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<p>
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Use OnCollapsing and OnCollapsed to perform actions before or after a node is
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collapsed on the tree view control.
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</p>
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</descr>
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<seealso>
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<link id="TCustomTreeView.Expand"/>
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<link id="TCustomTreeView.OnExpanding"/>
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<link id="TCustomTreeView.OnCollapsing"/>
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<link id="TCustomTreeView.OnCollapsed"/>
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<link id="TCustomTreeView.AutoExpand"/>
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<link id="TCustomTreeView.CanCollapse"/>
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<link id="TCustomTreeView.CanExpand"/>
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<link id="TCustomTreeView.Collapse"/>
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<link id="TCustomTreeView.States"/>
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<link id="TTVExpandedEvent"/>
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<link id="TTreeNode.Expand"/>
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<link id="TTreeNode.Expanded"/>
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<link id="TTreeNode.Visible"/>
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</seealso>
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</element>
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@ -33985,17 +34034,119 @@ Event handler signalled when a node on the tree view control has been expanded.
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<short>
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Event handler signalled prior to expanding a node on the tree view control.
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</short>
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<descr/>
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<seealso/>
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<descr>
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<p>
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<var>OnExpanding</var> is a <var>TTVExpandingEvent</var> property with the
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event handler signalled before a tree node is expanded on the tree view
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control. It is signalled (when assigned) from the CanExpand method, and allows
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the application to perform actions needed before the tree node is expanded to
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reveal its child nodes.
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</p>
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<p>
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Arguments for the event handler include:
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</p>
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<dl>
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<dt>
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Sender
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</dt>
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<dd>
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Object instance (TCustomTreeView) for the event.
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</dd>
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<dt>
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Node
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</dt>
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<dd>
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The TTreeNode instance to be expanded on the tree view control.
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</dd>
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<dt>
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AllowExpansion
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</dt>
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<dd>
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Boolean variable argument which indicates whether the tree node can be
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expanded on the control. Set AllowExpansion to <b>False</b> to prevent
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expansion of the tree node.
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</dd>
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</dl>
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<p>
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OnExpanding is <b>not</b> signalled if the tree node does not have any
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child nodes (HasChildren is <b>False</b>).
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</p>
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<p>
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Use OnExpanded to perform actions needed after a tree node has been expanded
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on the control.
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</p>
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<p>
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Use OnCollapsing and OnCollapsed to perform actions before or after a node is
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collapsed on the tree view control.
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</p>
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</descr>
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<seealso>
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<link id="TCustomTreeView.CanExpand"/>
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<link id="TCustomTreeView.NodeHasChildren"/>
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<link id="TCustomTreeView.OnExpanded"/>
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<link id="TCustomTreeView.OnCollapsing"/>
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<link id="TCustomTreeView.OnCollapsed"/>
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<link id="TTVExpandingEvent"/>
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<link id="TTreeNode.Expanded"/>
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<link id="TTreeNode.Visible"/>
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<link id="TTreeNode.HasChildren"/>
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</seealso>
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</element>
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<element name="TCustomTreeView.OnGetImageIndex">
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<short>
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Event handler signalled to get the ordinal position for the image displayed
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for a tree node on the control.
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on a tree node.
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</short>
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<descr/>
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<seealso/>
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<descr>
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<p>
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<var>OnGetImageIndex</var> is a <var>TTVExpandedEvent</var> property with the
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event handler signalled to get the index for an image displayed on a tree
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node. The index is an ordinal position in the Images assigned for the control.
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OnGetImageIndex allows a value assigned to the ImageIndex property in the tree
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node to be overridden, or set to a default value.
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</p>
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<p>
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OnGetImageIndex is signalled (when assigned) from the DoPaintNode method.
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It occurs when the Icon for a node is drawn using the Images for the tree view
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control. It is not a signalled if Images has not been assigned (contains
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<b>Nil</b>).
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</p>
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<p>
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Arguments to the event handler include:
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</p>
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<dl>
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<dt>
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Sender
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</dt>
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<dd>
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The object instance (TCustomTreeView) for the event.
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</dd>
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<dt>
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Node
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</dt>
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<dd>
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The TTreeNode instance examined in the handler routine.
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</dd>
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</dl>
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<p>
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The handler routine should select and assign a value to the ImageIndex
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property in Node; there is no way to provide the value as a separate argument
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or return value.
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</p>
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<p>
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Use OnGetSelectedIndex to get the image index for the a selected node on the
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tree view control.
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</p>
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</descr>
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<seealso>
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<link id="TCustomTreeview.Images"/>
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<link id="TCustomTreeview.DoPaintNode"/>
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<link id="TCustomTreeview.DoPaint"/>
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<link id="TCustomTreeview.OnGetSelectedIndex"/>
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<link id="TTreeNode.ImageIndex"/>
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<link id="TTVExpandedEvent"/>
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</seealso>
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</element>
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<element name="TCustomTreeView.OnGetSelectedIndex">
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@ -34003,8 +34154,55 @@ for a tree node on the control.
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Event handler signalled to get the ordinal position for the image displayed
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for a selected node on the tree view control.
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</short>
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<descr/>
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<seealso/>
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<descr>
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<p>
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<var>OnGetSelectedIndex</var> is a <var>TTVExpandedEvent</var> property with
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the event handler signalled to get the index position for the selected image
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on a tree view node. The index is an ordinal position in the Images assigned
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for the control.
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</p>
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<p>
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OnGetSelectedIndex is signalled (when assigned) from the OnGetSelectedIndex
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method, and occurs when a tree node is painted to the tree view control. It
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allows a value assigned to the SelectedIndex property in the tree node to be
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overridden, or set to a default value. OnGetSelectedIndex is <b>not</b>
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signalled if Images has not been assigned (is <b>Nil</b>).
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</p>
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<p>
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Arguments to the event handler include:
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</p>
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<dl>
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<dt>
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Sender
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</dt>
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<dd>
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The object instance (TCustomTreeView) for the event.
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</dd>
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<dt>
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Node
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</dt>
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<dd>
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The TTreeNode instance examined in the handler routine.
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</dd>
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</dl>
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<p>
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The handler routine should select and assign a value to the SelectedIndex
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property in Node; there is no way to provide the value as a separate argument
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or return value.
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</p>
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<p>
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Use OnGetImageIndex to get the image index for the a node which is not
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selected on the tree view control.
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</p>
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</descr>
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<seealso>
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<link id="TCustomTreeview.Images"/>
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<link id="TCustomTreeview.DoPaintNode"/>
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<link id="TCustomTreeview.DoPaint"/>
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<link id="TCustomTreeview.OnGetImageIndex"/>
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<link id="TTreeNode.SelectedIndex"/>
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<link id="TTVExpandedEvent"/>
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</seealso>
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</element>
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<element name="TCustomTreeView.OnHasChildren">
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@ -34012,10 +34210,46 @@ for a selected node on the tree view control.
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Event handler signalled to determine if a given node in the tree view has
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child nodes.
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</short>
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<descr/>
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<descr>
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<p>
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<var>OnHasChildren</var> is a <var>TTVHasChildrenEvent</var> property with the
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event handler signalled to determine whether a specified node has child nodes.
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It is signalled (when assigned) from the NodeHasChildren method, and allows
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the control to determine whether child nodes for a given node can be displayed
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on the control. It occurs when a TTreeNode instance gets the value for its
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HasChildren property and updates the States for the node.
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</p>
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<p>
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Arguments to the event handler include:
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</p>
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<dl>
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<dt>
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Sender
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</dt>
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<dd>
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The TCustomTreeView instance for the event.
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</dd>
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<dt>
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ANode
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</dt>
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<dd>
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The TTreeNode instance examine for child nodes in the handler routine.
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</dd>
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</dl>
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<p>
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The handler routine returns a Boolean value which indicates whether the
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specified node has child nodes which can be displayed on the control. The
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return value can be set to False - even when the tree node actually has child
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nodes. This allows properties in child nodes, like Data or Level, to be
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used to determine their effective visibility.
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</p>
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</descr>
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<seealso>
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<link id="TCustomTreeView.NodeHasChildren"/>
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<link id="TTVHasChildrenEvent"/>
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<link id="TTreeNode.HasChildren"/>
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<link id="TTreeNode.States"/>
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<link id="TTreeNode.Items"/>
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</seealso>
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</element>
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@ -34187,10 +34421,40 @@ display area.
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<short>
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Enables an expand/collapse (fold/unfold) icon for nodes with child nodes.
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</short>
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<descr/>
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<seealso/>
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<descr>
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<p>
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<var>ShowButtons</var> is a <var>Boolean</var> property which indicates
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whether an expand / collapse (fold) indicator is drawn for a tree node which
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has child nodes. The default value for the property is <b>True</b>, and causes
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an indicator to be drawn for qualified tree nodes.
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</p>
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<p>
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ShowButtons is a convenience property; its value is read from and written to
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the Options for the control. When set to <b>True</b>, the value tvoShowButtons
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is included in the Options property. When set to <b>False</b>, tvoShowButtons
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is excluded from Options. Changing the value for the property causes the
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control to be redrawn.
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</p>
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<p>
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ShowButtons is used during the paint process in the DoPaintNode method.
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</p>
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</descr>
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<seealso>
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<link id="TCustomTreeView.Options"/>
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<link id="TCustomTreeView.ExpandSignType"/>
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<link id="TCustomTreeView.ExpandSignColor"/>
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<link id="TCustomTreeView.ExpandSignSize"/>
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<link id="TCustomTreeView.ExpandSignWidth"/>
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<link id="TCustomTreeView.AutoExpand"/>
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<link id="TCustomTreeView.ShowLines"/>
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<link id="TCustomTreeView.ShowRoot"/>
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<link id="TCustomTreeView.ShowSeparators"/>
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<link id="TTreeNode.HasChildren"/>
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<link id="TTreeNode.Expanded"/>
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</seealso>
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</element>
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<!-- WIP: Here -->
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<element name="TCustomTreeView.ShowLines">
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<short>
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Enables or disables the horizontal and vertical lines which join nodes in the
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