treeview_unit.pas

一系列DELPHI的控件如何使用的例子,例子有的比较简单,但是能详细的说明了控件的使用,对许多刚涉足DELPHI的朋友会很有帮助的

unit treeview_Unit;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, FileCtrl, ComCtrls;

type
  TForm1 = class(TForm)
    TreeView1: TTreeView;
    DriveComboBox1: TDriveComboBox;
    FileListBox1: TFileListBox;
    procedure FormCreate(Sender: TObject);
    procedure TreeView1Expanding(Sender: TObject; Node: TTreeNode;
      var AllowExpansion: Boolean);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
var firstnode,dirnode:ttreenode;
    itemcount,index:integer;
    itemstr:string;
begin
    itemcount:=DriveComboBox1.Items.Count;
    firstnode:=treeview1.Items.GetFirstNode;
    for index:=0 to itemcount-1 do
    begin
    itemstr:=DriveComboBox1.Items[index];
    itemstr:=copy(itemstr,1,pos(':',itemstr));
    dirnode:=treeview1.Items.AddChild(firstnode,itemstr);
    dirnode.HasChildren:=true;
    dirnode.SelectedIndex:=1;
    end;

end;

procedure TForm1.TreeView1Expanding(Sender: TObject; Node: TTreeNode;
  var AllowExpansion: Boolean);
var
    dirnode:ttreenode;
    itemcount,index,level,icount:integer;
    itemstr,strpath:string;
    begin
    if node.Count = 0 then
    begin
    icount:=0;
    level:=node.Level ;
    dirnode:=node;
    strPath:=node.Text+'\' ;
    while level<0 do
    begin
    strPath:=dirnode.Parent.Text+'\'+strpath;
    dirnode:=dirnode.parent;
    level :=level -1;
    end;
    FileListBox1.Clear ;
    FileListBox1.Directory := strpath;
    ItemCount:= FileListBox1.Items.Count;
    for index:=0 to ItemCount -1 do
    begin
    itemstr:=filelistbox1.items[index];
    itemstr:= copy(ItemStr,2,pos(']',ItemStr)-2) ;
    if (itemstr<>'.') and (itemstr<>'..') then
    begin
    DirNode :=TreeView1.Items.AddChild(Node,itemstr );
    DirNode.HasChildren :=true;
    DirNode.ImageIndex := 0;
    DirNode.SelectedIndex := 1;
    icount:=icount+1;
    end;
    if icount = 0 then
    Node.HasChildren := false;
    end;
    end;
    end;
end.