树的快速创建算法,只需读一次数据库.
unit U_CreateTree;
interface
uses
Classes, ComCtrls, ADODB, SysUtils;
type
PPNodedata=^TNodeData;
TNodeData = record
ID:integer;//节点编号
PID:Integer;//父节点编号
Name:string;//节点名称
child:PPNodedata;//孩子节点
brather:PPNodedata;//兄弟节点
end;
PNodeData = PPNodeData;
TTreeFill1 = class(TThread)
TV: TTreeView;
RootID:Integer;
ptr:PPNodeData;
root:PPNodeData;//根节点
PointNode:PPNodeData;
s:array[0..10000] of PPNodeData;
constructor Create(Root_Id:integer;ATreeView: TTreeView);
private
procedure AddTree(Node: TTreeNode; PN: PNodeData);
protected
procedure Execute; override;
end;
implementation
uses
U_Main, DateUtils;
var count,nodeCount:Integer;
//----------
constructor TTreeFill1.Create(Root_Id:integer;ATreeView:TTreeView);
begin
TV:= ATreeView;
TV.Items.Clear;
RootID:=Root_Id;
inherited Create(False);
end;
//----------
procedure TTreeFill1.Execute;
var Query: TADOQuery;
i,j:Integer;
Node: TTreeNode;
begin
FreeOnTerminate := True;
TV.Items.Clear;
with Query do
begin
Query := TADOQuery.Create(nil);
Connection := frm_Main.ADOC_SQL;//需要更改
Close;
SQL.Clear;
SQL.Add('Select * from 部门表 order by 部门编号 ');
Open;
first;
count:=recordcount;
if count>0 then
begin
for i:=0 to recordcount-1 do
begin
new(PointNode);
PointNode^.child:=nil;
PointNode.brather:=nil;
PointNode^.ID:=fieldbyname('部门编号').AsInteger;
PointNode^.PID:=fieldbyname('父部门编号').AsInteger;
PointNode^.Name:=fieldbyname('部门名称').AsString;
s[i]:= PointNode;
next;
end;
end;
free;
end;
//------创建树----------
for i:=0 to count-1 do
begin
for j:=0 to count-1 do
if s[i]^.PID=s[j]^.ID then
begin
if s[j]^.child=nil then
s[j]^.child:=s[i]
else
begin
ptr:= s[j]^.child;
while (ptr.brather<>nil) do
ptr:=ptr^.brather;
ptr.brather:=s[i];
end;
end;
end;
for i:=0 to count-1 do
if s[i]^.ID=RootID then
begin
root:=s[i]; //根节点
break;
end;
Node:=TV.Items.AddObject(nil,Root^.Name,Root);//创建树的根节点
nodeCount:=0;
Node.ImageIndex := 0;
Node.SelectedIndex := 2;
AddTree(Node,root);
end;
procedure TTreeFill1.AddTree(Node:TTreeNode;PN:PNodeData);
var
nNode: TTreeNode;
PNode,q: PNodeData;
begin
PNode:=PN;
if PNode.child<>nil then
begin
q:=PNode.child;
while (q<>nil) do
begin
nNode:=TV.Items.AddchildObject(Node,q^.Name,q);
nodeCount:=nodeCount+1;
AddTree(nNode,q);
q:=q^.brather;
end;
end;
end;
end.
作者qq：13575437 |
