Mega Code Archive
Treeview Check Box
<![CDATA[
Title: Treeview Check Box
Question: How to Insert CheckBox and treeview
Answer:
Zarko Gajic, BSCS
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}
interface
uses
Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
Dialogs, ComCtrls, ImgList, StdCtrls;
type
TForm1 = class(TForm)
TreeView1: TTreeView;
ImageList1: TImageList;
Button1: TButton;
Memo1: TMemo;
procedure TreeView1Click(Sender: TObject);
procedure TreeView1KeyDown(Sender: TObject; var Key: Word;
Shift: TShiftState);
procedure FormCreate(Sender: TObject);
procedure TreeView1Collapsing(Sender: TObject; Node: TTreeNode;
var AllowCollapse: Boolean);
procedure Button1Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
const
//ImageList.StateIndex=0 has some bugs, so we add one dummy image to position 0
cFlatUnCheck = 1;
cFlatChecked = 2;
cFlatRadioUnCheck = 3;
cFlatRadioChecked = 4;
var
Form1: TForm1;
implementation
{$R *.dfm}
procedure ToggleTreeViewCheckBoxes(Node:TTreeNode; cUnChecked, cChecked, cRadioUnchecked, cRadioChecked:integer);
var
tmp:TTreeNode;
begin
if Assigned(Node) then
begin
if Node.StateIndex = cUnChecked then
Node.StateIndex := cChecked
else if Node.StateIndex = cChecked then
Node.StateIndex := cUnChecked
else if Node.StateIndex = cRadioUnChecked then
begin
tmp := Node.Parent;
if not Assigned(tmp) then
tmp := TTreeView(Node.TreeView).Items.getFirstNode
else
tmp := tmp.getFirstChild;
while Assigned(tmp) do
begin
if (tmp.StateIndex in [cRadioUnChecked,cRadioChecked]) then
tmp.StateIndex := cRadioUnChecked;
tmp := tmp.getNextSibling;
end;
Node.StateIndex := cRadioChecked;
end; // if StateIndex = cRadioUnChecked
end; // if Assigned(Node)
end; (*ToggleTreeViewCheckBoxes*)
procedure TForm1.TreeView1Click(Sender: TObject);
var
P:TPoint;
begin
GetCursorPos(P);
P := TreeView1.ScreenToClient(P);
if (htOnStateIcon in TreeView1.GetHitTestInfoAt(P.X,P.Y)) then
ToggleTreeViewCheckBoxes(
TreeView1.Selected,
cFlatUnCheck,
cFlatChecked,
cFlatRadioUnCheck,
cFlatRadioChecked);
end;
procedure TForm1.TreeView1KeyDown(Sender: TObject; var Key: Word;
Shift: TShiftState);
begin
if (Key = VK_SPACE) and Assigned(TreeView1.Selected) then
ToggleTreeViewCheckBoxes(TreeView1.Selected,cFlatUnCheck,cFlatChecked,cFlatRadioUnCheck,cFlatRadioChecked);
end; (*TreeView1KeyDown*)
procedure TForm1.FormCreate(Sender: TObject);
var
i: integer;
begin
TreeView1.FullExpand;
end; (*FormCreate*)
procedure TForm1.TreeView1Collapsing(Sender: TObject; Node: TTreeNode;
var AllowCollapse: Boolean);
begin
AllowCollapse := false;
end; (*TreeView1Collapsing*)
procedure TForm1.Button1Click(Sender: TObject);
var
BoolResult:boolean;
tn : TTreeNode;
begin
if Assigned(TreeView1.Selected) then
begin
tn := TreeView1.Selected;
BoolResult := tn.StateIndex in [cFlatChecked,cFlatRadioChecked];
Memo1.Text := tn.Text + #13#10 + 'Selected: ' + BoolToStr(BoolResult, True);
end;
end; (*Button1Click*)
end.
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