认真研究如下代码：DBTreeView--TreeView直接连接数据表
unit Unit1;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls, DB, DBTables, ComCtrls, Grids, DBGrids, ExtCtrls,
DBCtrls, Mask, ImgList;
type
TForm1 = class(TForm)
TreeView1: TTreeView;
ImageList1: TImageList;
DataSource1: TDataSource;
DBEdit1: TDBEdit;
Label1: TLabel;
Label2: TLabel;
DBEdit2: TDBEdit;
Table1: TTable;
Label3: TLabel;
DBNavigator1: TDBNavigator;
Label4: TLabel;
DBEdit3: TDBEdit;
DBEdit4: TDBEdit;
procedure FormCreate(Sender: TObject);
procedure TreeView1Change(Sender: TObject; Node: TTreeNode);
procedure DataSource1StateChange(Sender: TObject);
procedure Table1AfterInsert(DataSet: TDataSet);
procedure Table1BeforeDelete(DataSet: TDataSet);
procedure Table1BeforeEdit(DataSet: TDataSet);
procedure Table1AfterDelete(DataSet: TDataSet);
procedure Table1AfterPost(DataSet: TDataSet);
private
function GetFieldList: TStringList;
{ Private-Declarationen }
public
{ Public-Declarationen }
end;
var
Form1: TForm1;
FieldList: TStringList;
implementation
uses TreeFunc;
{$R *.DFM}
function TForm1.GetFieldList: TStringList;
begin
FieldList.clear;
FieldList.add(Table1.fieldbyname('Country').asstring);
FieldList.add(Table1.fieldbyname('city').asstring);
FieldList.add(Table1.fieldbyname('Company').asstring);
Result := FieldList;
end;
procedure TForm1.FormCreate(Sender: TObject);
begin
FieldList := TStringList.create;
TreeView1.items.BeginUpdate;//forbid treeview update
Table1.first;
while not Table1.eof do
begin
TreeAddItem(TreeView1, GetFieldList, Table1.getBookmark, false);//生成结点
Table1.next;
end;
FieldList.clear;
TreeView1.Alphasort;
TreeView1.items.Endupdate;
//make first record selected:
TreeView1.items[2].selected := true;
end;
procedure TForm1.TreeView1Change(Sender: TObject; Node: TTreeNode);
begin
Datasource1.enabled := Node.data <> nil;
if DataSource1.enabled then Table1.Gotobookmark(node.data);
end;
procedure TForm1.DataSource1StateChange(Sender: TObject);
var
ItemList: TStringList;
Node: TTreeNode;
begin
end;
procedure TForm1.Table1AfterInsert(DataSet: TDataSet);
begin
FieldList.clear;
end;
procedure TForm1.Table1BeforeDelete(DataSet: TDataSet);
begin
GetFieldList;
end;
procedure TForm1.Table1BeforeEdit(DataSet: TDataSet);
begin
GetFieldList;
end;
procedure TForm1.Table1AfterDelete(DataSet: TDataSet);
var
CascadeDeleteLevel: Integer;
begin
CascadeDeleteLevel := 0;
TreeDeleteItem(TreeView1, FieldList, CascadeDeleteLevel);
end;
procedure TForm1.Table1AfterPost(DataSet: TDataSet);
begin
TreeView1.items.beginUpdate;
if FieldList.count > 0 then TreeDeleteItem(TreeView1, Fieldlist, 0);
TreeView1.selected := TreeAddItem(TreeView1, GetFieldlist, Table1.getbookmark, True);
TreeView1.items.endUpdate;
end;
end.
///------------------------
unit TreeFunc;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, ComCtrls, DB, Forms, Dialogs;
function TreeFindItem(Sender: TTreeView; NodeItem: TTreeNode; Name: String): TTreeNode;
function TreeAddItem(Sender: TTreeView; ItemList: TStrings; Bookmark: TBookmark; Resort: Boolean): TTreeNode;
function TreeGetItem(Sender: TTreeView; ItemList: TStrings): TTreeNode;
procedure TreeDeleteItem(Sender: TTreeView; ItemList: TStrings; Level: Integer);
implementation
function TreeAddItem(Sender: TTreeView; ItemList: TStrings; Bookmark: TBookmark; Resort: Boolean): TTreeNode;
var
ThisNode, Node: TTreeNode;
I: Integer;
begin
Node := nil; //nil = level 0 has no parent node
//this is checked by TreeFindItem
for I := 0 to Itemlist.count -1 do
begin //for
ThisNode := TreeFindItem(Sender, node, Itemlist[i]);
if ThisNode <> nil then
Node := ThisNode
else
begin
if I < Itemlist.count -1 then
begin
if I = 0 then
Node := Sender.items.Add(Node, Itemlist[i])
else
Node := Sender.items.AddChild(Node, Itemlist[i]);
end
else
begin
if I = 0 then
Node := Sender.items.AddObject(Node, Itemlist[i], Bookmark)
else
Node := Sender.items.AddChildObject(Node, Itemlist[i], Bookmark);
end;
Node.stateIndex := Node.level + 1;
if Resort and (Node.parent <> nil) then Node.parent.alphasort;
end;
end; //for
Result := Node;
end;
function TreeFindItem(Sender: TTreeView; NodeItem: TTreeNode; Name: String): TTreeNode;
begin
if NodeItem = nil then NodeItem := Sender.items.getfirstnode
else NodeItem := NodeItem.getfirstchild;
//NodeItem is now the first item of the desired level
//if this level has no items, NodeItem is nil
if (NodeItem <> nil) and (NodeItem.text <> Name) then
repeat
NodeItem := NodeItem.getnextsibling;
until (NodeItem = nil) or (NodeItem.text = Name);
Result := NodeItem;
end;
function TreeGetItem(Sender: TTreeView; ItemList: TStrings): TTreeNode;
begin
Result := TreeAddItem(Sender, Itemlist, nil, false);
end;
procedure TreeDeleteItem(Sender: TTreeView; ItemList: TStrings; Level: Integer);
var
Node, Parent: TTreeNode;
begin
Node := TreeGetItem(Sender, ItemList);
while Node.level >= Level do
begin
Parent := Node.parent;
Node.delete;
if (Parent = nil) or (Parent.hasChildren) then break;
Node := Parent;
end;
end;
end.
