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Docs: LCL/shellctrls. Adds and updates topics for changes in efd6c169. Issue #40022.

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* Adds: TExpandCollapseMode, TCustomShellTreeView.Collapse.
* Updates: TCustomShellTreeView.CanExpand.
This commit is contained in:
dsiders 2022-11-29 20:56:57 +00:00
parent 6ab3629c14
commit aac79c4885
1 changed files with 127 additions and 11 deletions
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138
docs/xml/lcl/shellctrls.xml
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@ -145,6 +145,44 @@ It is also passed as an argument to methods in
<short>File masks are case sensitive.</short>
</element>
<element name="TExpandCollapseMode">
<short>
Indicates actions performed for child nodes when a shell tree node is expanded or collapsed.
</short>
<descr>
<p>
<var>TExpandCollapseMode</var> is an enumerated type with values that indicate
the actions performed for child nodes when a shell tree node is expanded or
collapsed. TExpandCollapseMode is the type used to implement the
ExpandCollapseMode property in TCustomShellTreeView.
</p>
</descr>
<seealso>
<link id="TCustomShellTreeView.ExpandCollapseMode"/>
<link id="TCustomShellTreeView.CanExpand"/>
<link id="TCustomShellTreeView.Collapse"/>
</seealso>
<version>
Added in LCL version 2.4.
</version>
</element>
<element name="TExpandCollapseMode.ecmRefreshedExpanding">
<short>
Clear existing children before expanding.
</short>
</element>
<element name="TExpandCollapseMode.ecmKeepChildren">
<short>
Do not clear children of previously expanded tree nodes when they are
collapsed.
</short>
</element>
<element name="TExpandCollapseMode.ecmCollapseAndClear">
<short>
Clear children when a node is collapsed.
</short>
</element>
<element name="TAddItemEvent">
<short>
Specifies an event handler signalled when an item is added to a shell control.
@ -222,6 +260,7 @@ methods implemented in the descendent classes.
<element name="TCustomShellTreeView.FPopulateDelayed"/>
<element name="TCustomShellTreeView.FRoot"/>
<element name="TCustomShellTreeView.FShellListView"/>
<element name="TCustomShellTreeView.FExpandCollapseMode"/>
<element name="TCustomShellTreeView.FFileSortType"/>
<element name="TCustomShellTreeView.FInitialRoot"/>
<element name="TCustomShellTreeView.FUseBuiltinIcons"/>
@ -534,13 +573,19 @@ notification.
<element name="TCustomShellTreeView.CanExpand">
<short>
Determines if the specified tree node can be expanded in the shell control.
Determines if the specified tree node can be expanded in the shell tree view
control.
</short>
<descr>
<p>
<var>CanExpand</var> is an overridden <var>Boolean</var> function used to
determine if the specified tree node can be expanded in the shell control.
<var>Node</var> contains the <var>TTreeNode</var> examined in the method.
determine if the specified tree node can be expanded in the shell tree view
control. CanExpand ensures that the shell control reflects the current content
in the local file system during execution of the method.
</p>
<p>
<var>Node</var> contains the <var>TTreeNode</var> examined and updated in the
method.
</p>
<p>
CanExpand calls the inherited method to signal the OnExpanding event handler
@ -549,12 +594,30 @@ returns <b>False</b>.
</p>
<p>
<var>CanExpand</var> temporarily disables the <var>AutoExpand</var>
functionality in the shell control, and removes all child tree nodes in
<var>Node</var>. The child nodes are re-created using the
<var>PopulateTreeNodeWithFiles</var> method. This ensures that the shell
control reflects the current content in the local file system during
execution of the method. The value in <var>AutoExpand</var> is restored to
its original value prior to exiting from the method.
functionality in the shell tree view control, and updates the child nodes in
Node when needed. The value in ExpandCollapseMode is used to determine whether
child nodes are created or recreated. The following actions are performed for
the ExpandCollapseMode property values:
</p>
<dl>
<dt>ecmRefreshedExpanding</dt>
<dd>
Deletes existing child nodes and calls PopulateTreeNodeWithFiles to reload
entries for the path in Node.
</dd>
<dt>ecmKeepChildren</dt>
<dd>
Keeps existing child nodes. Calls PopulateTreeNodeWithFiles if the existing
child node count is 0 (zero).
</dd>
<dt>ecmCollapseAndClear</dt>
<dd>
Calls PopulateTreeNodeWithFiles to load files for the path in Node.
</dd>
</dl>
<p>
The value in <var>AutoExpand</var> is restored to its original value prior to
exiting from the method.
</p>
<p>
The entire update process is done in a BeginUpdate / EndUpdate block to
@ -562,22 +625,75 @@ reduce the number of screen refreshes in the method.
</p>
</descr>
<seealso>
<link id="TCustomShellTreeView.ExpandCollapseMode"/>
<link id="TCustomShellTreeView.PopulateTreeNodeWithFiles"/>
<link id="TShellTreeView.AutoExpand"/>
<link id="TShellTreeNode"/>
<link id="TTreeNode"/>
<link id="#lcl.comctrls.TCustomTreeView.AutoExpand">TCustomTreeView.AutoExpand</link>
</seealso>
<version>
Modified in LCL version 2.4 to use ExpandCollapseMode to control actions
performed for child nodes.
</version>
</element>
<element name="TCustomShellTreeView.CanExpand.Result">
<short>
<b>True</b> when the tree node contains child nodes and be expanded.
<b>True</b> when the tree node can be expanded to display child nodes.
</short>
</element>
<element name="TCustomShellTreeView.CanExpand.Node">
<short>Tree node examined in the method.</short>
</element>
<element name="TCustomShellTreeView.Collapse">
<short>
Removes child nodes (if needed) when the specified tree node is collapsed.
</short>
<descr>
<p>
<var>Collapse</var> is an overridden method in <var>TCustomShellTreeView</var>
used to update the tree node specified in <var>Node</var> when it changes from
the expanded to the collapsed state. It uses the value in the
ExpandCollapseMode property to determine whether existing child nodes are
removed from the collapsed tree node.
</p>
<p>
When ExpandCollapseMode is set to ecmCollapseAndClear, the DeleteChildren
method in Node is called to free its child nodes. The operation is performed
in a BeginUpdate / EndUpdate block to prevent updates to the control while the
child nodes are deleted.
</p>
<p>
Collapse calls the inherited method prior to exit to update scroll bars on the control and to signal the OnCollapsed event handler (when assigned).
</p>
<p>
No actions are performed in the method when ComponentState is set to
csDestroying.
</p>
<p>
Collapse is called when a tree node has executed its Collapse method.
</p>
</descr>
<seealso>
<link id="TCustomShellTreeView.ExpandCollapseMode"/>
<link id="#lcl.comctrls.TCustomTreeView.Collapse">TCustomTreeView.Collapse</link>
<link id="#lcl.comctrls.TCustomTreeView.OnCollapsed">TCustomTreeView.OnCollapsed</link>
<link id="#lcl.comctrls.TTreeNode.Collapse">TTreeNode.Collapse</link>
<link id="#lcl.comctrls.TTreeNode.HasChildren">TTreeNode.HasChildren</link>
<link id="#lcl.comctrls.TTreeNode.DeleteChildren">TTreeNode.DeleteChildren</link>
<link id="#rtl.classes.TComponent.ComponentState">TComponent.ComponentState</link>
</seealso>
<version>
Added in LCL version 2.4.
</version>
</element>
<element name="TCustomShellTreeView.Collapse.Node">
<short>
Tree node affected in the method.
</short>
</element>
<element name="TCustomShellTreeView.DrawBuiltInIcon">
<short>Draws the Shell Icon for the specified tree node.</short>
<descr>
@ -743,7 +859,7 @@ Please note: Values in the <var>Items</var> property are populated when the
</p>
</descr>
<version>
Modified in LCL version 2.4 to initialize the PathDelimiter property and internal find options.
Modified in LCL version 2.4 to initialize the PathDelimiter property and internal find options.
</version>
<seealso>
<link id="TCustomShellTreeView.ObjectTypes"/>