2023年6月22日发(作者：)

delphi TreeView详解

property AutoExpand: Boolean;

AutoExpand

Set AutoExpand to true to cause the selected item to expand

and the unselected items to collapse.

property BorderStyle: TBorderStyleTBorderStyle;

Set BorderStyle to specify whether the tree view control should

be outlined with a single-line border. These are the possible

values:

BorderStyle

Value Meaning

bsNone No visible border

bsSingle Single-line border

property Canvas: TCanvas;

Canvas

Use the Canvas property to paint to the canvas from the

OnCustomDraw and OnCustomDrawItem event handlers.

property ChangeDelay: Integer;

Use ChangeDelay to get or set the delay, in milliseconds,

ChangeDelay

between when a node is selected and when the OnChange

event occurs.

Set the ChangeDelay to 50 milliseconds to emulate the

behavior of the tree-view control used in Windows Explorer.

property DropTarget: TTreeNode;

Read DropTarget to determine whether a node in the tree view

DropTarget

is drawn as the target of a drag and drop operation. Set

DropTarget when specifying a particular node in the tree view

as the drop target of a dragged item.

Note: When DropTarget is set, the application must still handle delphi TreeView详解

the actual logic of accepting the dragged object by the

indicated node.

property HideSelection: Boolean;

Use HideSelection to specify whether the user is given visual

HideSelection feedback about the current selection in the tree view when it

does not have focus. If true, the selected node is not visually

distinct from other nodes until focus returns to the control. If

false, the node always appears selected.

property HotTrack: Boolean;

HotTrack Set HotTrack to true to provide visual feedback about which

item is under the mouse. Set HotTrack to false to suppress the

visual feedback about which item is under the mouse.

property Images: TCustomImageList;

Images

Use Images to provide a customized list of bitmaps that can be

displayed to the left of a node’s label. Individual nodes specify

the image from this list that should appear by setting their

ImageIndex property.

property Indent: Integer;

Indent

Use Indent to determine how far child nodes are indented from

their parent nodes when the parent is expanded.

property Items: TTreeNodes;

Individual nodes in a tree view are TTreeNode objects. These

individual nodes can be accessed by using the Items property

Items

along with the item's index into the tree view. For example, to

access the second item in the tree view, you could use the

following code.

MyTreeNode := [1];

When setting this property at design-time in the Object delphi TreeView详解

Inspector the Tree View Items Editor appears. Use the New

Item and New SubItem buttons to add items to the tree view.

Use the Text property to modify what text is displayed in the

label of the item.

At run-time nodes can be added and inserted by using the

TTreeNodes methods AddChildFirst, AddChild,

AddChildObjectFirst, AddChildObject, AddFirst, Add,

AddObjectFirst, AddObject, and Insert.

Note: Accessing tree view items by index can be

time-intensive, particularly when the tree view contains many

items. For optimal performance, try to design your application

so that it has as few dependencies on the tree view’s item index

as possible.

property MultiSelect: Boolean;

MultiSelect Set MultiSelect to specify whether users can select multiple

nodes using the Control and Shift keys. A selection style must

also be chosen in MultiSelectStyle.

type

TMultiSelectStyles = (msControlSelect, msShiftSelect,

msVisibleOnly, msSiblingOnly);

TMultiSelectStyle = set of TMultiSelectStyles;

MultiSelectStyle property MultiSelectStyle: TMultiSelectStyle;

MultiSelectStyle determines how multiple selections are made

when MultiSelect is true. MultiSelectStyle must include at least

one of the following values.

msControlSelect: Clicking on any node with the Control key

pressed toggles the selection of that node. delphi TreeView详解

msShiftSelect: Clicking on any node with the Shift key press

selects that node, the last single node selected, and the nodes

in between. All other nodes are deselected.

msVisibleOnly Multiple: selections with the Shift key do not

include child nodes of collapsed nodes.

msSiblingOnly: Selected nodes are restricted to a single set of

siblings.

If msControlSelect or msShiftSelect are in effect, the last

singly-selected node becomes the primary selection,

referenced by Selections[0]. The primary selection is the

anchor for extended selections using the Shift key.

property ReadOnly: Boolean;

ReadOnly

Use ReadOnly to specify whether the user can edit the nodes of

the tree view. If ReadOnly is true, the user can expand and

collapse nodes, but can’t edit their labels. If ReadOnly is false,

the user can edit the labels as well. The default value is false.

property RightClickSelect: Boolean;

Use RightClickSelect to allow the Selected property to indicate

nodes the user clicks with the right mouse button. If

RightClickSelect is true, the value of Selected is the value of the

node last clicked with either the right or left mouse button. If

RightClickSelect is false, the value of Selected is the node last

RightClickSelect

clicked using the left mouse button.

RightClickSelect affects only the value of the Selected

property. It does not cause the tree view to highlight a new

node if the node is selected using the right mouse button.

Note: RightClickSelect must be set to true before the user delphi TreeView详解

right-clicks the tree view for it to affect the value of the

Selected property.

property RowSelect: Boolean;

RowSelect

Set RowSelect to true to cause the entire row of the selected

item to be highlighted.

RowSelect is ignored if ShowLines is true.

property Selected: TTreeNode;

Read Selected to access the selected node of the tree view. If

there is no selected node, the value of Selected is nil (Delphi)

or NULL (C++).

Set Selected to set a node in the tree view. When a node

becomes selected, the tree view's OnChanging and OnChange

events occur. Also, if the specified node is the child of a

collapsed parent item, the parent's list of child items is

expanded to reveal the specified node. In this case, the tree

Selected view's OnExpanded and OnExpanding events occur as well.

If the RightClickSelect property is true, the value of Selected is

the last node that was clicked in the tree view, even if it was

clicked with the right mouse button. This may differ from the

node that is highlighted to indicate selection.

If the MultiSelect property is true and the MultiSelectStyle

property includes msControlSelect, then Selected returns the

last node clicked on, even if that click deselected the node. For

a current selection status when MultiSelect is true, refer to the

Selections property.

property SelectionCount: Cardinal;

SelectionCount

SelectionCount returns the number of nodes currently

selected. delphi TreeView详解

property Selections[Index: Integer]: TTreeNode;

Selections returns one of selected nodes. The maximum value

Selections of Index is SelectionCount-1. If more than one node is

selected, Selections[0] is the primary selected node. This node

is the starting point for extended selections if MultiSelectStyle

includes msShiftSelect.

property ShowButtons: Boolean;

ShowButtons

If ShowButtons is true, a button will appear to the left of each

parent item. The user can click the button to expand or collapse

the child items as an alternative to double-clicking the parent

item.

property ShowLines: Boolean;

ShowLines

If ShowLines is true, lines linking child nodes to their parent

nodes are displayed. Nodes at the root of the hierarchy are not

automatically linked. To link nodes at the root, the ShowRoot

property must also be set to true.

property ShowRoot: Boolean;

ShowRoot

To show lines connecting top-level nodes to a single root, set

the tree view's ShowRoot and ShowLines properties to true.

property SortType: TSortType;

Once a tree view is sorted, the original hierarchy is lost. That is,

setting the SortType back to stNone will not restore the original

order of items. These are the possible values:

SortType

stNone: No sorting is done.

stData: The items are sorted when the Data object or SortType

is changed.

stText: The items are sorted when the Caption or SortType is delphi TreeView详解

changed.

stBoth: The items are sorted when either the Data object, the

Caption or SortType is changed

Optionally, the OnCompare event can be hooked to handle

comparisons.

property StateImages: TCustomImageList;

StateImages Use StateImages to provide a set of bitmaps that reflect the

state of tree view nodes. The state image appears as an

additional image to the left of the item's icon.

property ToolTips: Boolean;

Set ToolTips to true to specify that items in the tree view

ToolTips control have tool tips (Help Hints).

Specify the ToolTip text in an OnHint event handler using the

Hint property.

property TopItem: TTreeNode;

TopItem

When TopItem is changed, the tree view scrolls vertically so

that the specified node is topmost in the list view.