特急，冒汗！！！有关treeview 的分层显示问题？？？

Question

MainTree.items.add(nil,'树根')
        with MainTree do
        begin
            Ln:=Items.AddChild(Items[0].item[6],'K     蜡烛线');
            LN.ImageIndex:=2;      Ln.SelectedIndex:=2;
            New(P);     p.Value:=Integer(mtKLIne);  P.ValueType:=IsMainMap;
            Ln.Data:=P;
            Ln:=Items.AddChild(Items[0].item[6],'Bar   美国线');
            LN.ImageIndex:=2;      Ln.SelectedIndex:=2;
            Ln.Data:=P;
            Ln:=Items.AddChild(Items[0].item[6],'TWR   宝塔线');
            LN.ImageIndex:=2;      Ln.SelectedIndex:=2;
            Ln.Data:=P;
        end;

Answer 1

如果数据量很在，就用treeview和数组；
或者，如上者；
Node,Node_1:TreeNode;
Node := TreeView.Items.add(Nil,String);//level := 0;
Node_1 := TreeView.Items.AddChild( Node_1 , String);//level := 1;
就这样类推
如：
          
//=================================
procedure Txsjbxxform.TreeViewCreate;
var
  Node_1 , Node_2 : TTreeNode;
begin
  with DataModuleForm.xsxxQuery2 do
  begin
    Close;
    with SQL do
    begin
      Clear;
      Add('select Distinct bjmc from xsjbxx ' ) ;
    end;
    Open;
    First;
    while Not (DataModuleForm.xsxxQuery2.Eof ) do
    begin
      Node_1 := TreeView1.Items.Add(Nil,FieldByName('bjmc').AsString );
      Node_1.ImageIndex := 0;
      Node_1.SelectedIndex := 1;
      with DataModuleForm.xsxxQuery3 do
      begin
        Close;
        with SQL do
        begin
          Clear;
          Add('select * from xsjbxx where bjmc = :Value');
        end;
        Parameters.Items[0].Value := DataModuleForm.xsxxQuery2.FieldByName('bjmc').AsString ;
        Open;
        First;
        while Not ( DataModuleForm.xsxxQuery3.Eof ) do
        begin
          Node_2 := TreeView1.Items.AddChild( Node_1 , FieldByName('xm').AsString + '-->' + FieldByName('bh').AsString);
          Node_2.ImageIndex := 2;
          Node_2.StateIndex := 3;
          Node_2.SelectedIndex := 3;
          Next;
        end;
      end;
      Next;
    end;
  end;

Answer 2

treeview的问题我上次也费了很长时间。因为数据量很大，所以合适的做法是在节点扩展的时候读取数据，即OnExpanding事件。在接点未扩展时，可以先赋予它一个临时数据，节点展开的同时把它删除。具体处理如下：
procedure TTree.FormCreate(Sender: TObject);
begin
  tv.Items.Add(tv.TopItem,nodeTop).Selected:=True;
  tv.Items.AddChild(tv.Selected,'temp');
end;procedure TTreeV.tvExpanding(Sender: TObject; Node: TTreeNode;
  var AllowExpansion: Boolean);
begin
  tempNode:=Node.getFirstChild;
  if (Node.Count>1) or (tempNode.Text<>'temp') then Exit;
  with ADOQ do
  begin
    if Active then Close;
    SQL.Clear;
    SQL.Add('select *  from Tree ');
    Open;
    First;
    while not Eof do
    begin
      if trim(FieldByName('PNAME').AsString)=Copy  (tempNode.Parent.Text,Pos('-',tempNode.Parent.Text)+1,Length (tempNode.Parent.Text)) then
      begin
        tempNode:=tv.Items.Add(tempNode,FieldByName('ID').AsString+'-'+FieldByName('Name').AsString);
        tempNode.ImageIndex:=tempNode.Level;
        tv.Items.AddChild(tempNode,'temp');
      end;
      Next;
    end;
  end;
  if Node.getFirstChild.Text='temp' then Node.getFirstChild.Delete;
end;如果涉及到多个数据表就更麻烦了，别人曾给我建议用数据流，具体我也没去试国，这边还有一个不错的别人的例子，你可以参考一下

Answer 3

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ComCtrls, DB, DBTables, ImgList, ExtCtrls, DBCtrls, StdCtrls,
  Mask, Grids, DBGrids;
const
  cTreeCodeFormat='122222';//
  cTreeMaxLevel=6;
  cTreeRootTxt='单位字典';
type
  TForm1 = class(TForm)
    tree: TTreeView;
    ImageList1: TImageList;
    Table1: TTable;
    Database1: TDatabase;
    DBEdit1: TDBEdit;
    DBEdit2: TDBEdit;
    DataSource1: TDataSource;
    DBNavigator1: TDBNavigator;
    DBGrid1: TDBGrid;
    procedure Table1NewRecord(DataSet: TDataSet);
    procedure Table1BeforeEdit(DataSet: TDataSet);
    procedure Table1AfterDelete(DataSet: TDataSet);
    procedure Table1AfterInsert(DataSet: TDataSet);
    procedure Table1AfterPost(DataSet: TDataSet);
    procedure Table1AfterEdit(DataSet: TDataSet);
    procedure Table1BeforeDelete(DataSet: TDataSet);
    procedure FormCreate(Sender: TObject);
    procedure treeClick(Sender: TObject);
  private
    { Private declarations }
    mystate,
    gNodeID:string;
    gNode:TTreeNode;
    gNodelevel:integer;
    procedure setFieldMask;    procedure LoadTree(treeDB:TDBDataSet);
    procedure UpdateTree(curNode:TTreeNode;nodeTxt:string;state:string);
    function GetNodeLevel(sFormat,sCode:string):integer;
  public
    { Public declarations }
  end;var
  Form1: TForm1;implementation{$R *.dfm}
procedure TForm1.setFieldMask;
var
  i,j:integer;
  maskStr:string;
  setField:TField;
begin
  setField:=table1.FieldByName('dwbm');
  if (gNodeID<>'') and (gNodelevel<cTreeMaxLevel) then
  begin
    maskStr:='';
    if setField.DataSet.state=dsInsert then
      j:=Length(gNodeID)
    else
      j:=Length(gNodeID)-2;
    for i:=1 to j do
    begin
      maskStr:=maskStr+'\'+gNodeID[i];
    end;
    setField.EditMask:='!'+maskStr+'00;1;?';
  end
  else begin
    setField.DataSet.Cancel;
  end;
end;procedure TForm1.LoadTree(treeDB:TDBDataSet);
var
  curID,nodeTxt:string;
  level,chindex,cnode,num:integer;
  mynode:array[0..6]of TTreeNode;
begin
  Screen.Cursor:=crHourGlass;
  tree.Enabled:=True;
  tree.Items.clear;
  level:=0;
  num:=1;
  mynode[level]:=tree.Items.Add(Tree.TopItem,cTreeRootTxt);
  mynode[level].ImageIndex:=1;
  with treeDB do
  begin
    try
    if not Active then open;
    first;
    while not EOF do
    begin
      curID:=trim(FieldByName('dwbm').AsString );
      nodeTxt:=curID+'-'+trim(FieldByName('dwmc').AsString );
      level:=GetNodeLevel(cTreeCodeFormat,curID);
      if level>0 then
      begin
        mynode[level]:=tree.Items.addchild(mynode[level-1],nodeTxt);
        mynode[level].ImageIndex:=2;      end;
      next;
    end;
    finally
      close;
    end;
    mynode[0].Expand(False);
    Screen.Cursor:=crDefault;
  end;
end;

Answer 4

procedure TForm1.UpdateTree(curNode:TTreeNode;nodeTxt:string;state:string);
begin
  if state='add' then
  begin
    curNode:=tree.Items.AddChild(curNode,nodeTxt);
    curNode.ImageIndex:=2;
  end;
  if state='del' then curNode.Delete;
  if state='edi' then curNode.Text:=nodeTxt;end;function TForm1.GetNodeLevel(sFormat,sCode:string):integer;
var
  i,level,iLen:integer;
begin
  level:=-1;
  iLen:=0;
  if (sFormat<>'') and (sCode<>'')  then
  begin
    for i:=1 to Length(sFormat) do
    begin
      iLen:=iLen+StrToInt(sFormat[i]);
      if Length(sCode)=iLen then
      begin
        level:=i;
        break;
      end;
    end;
    result:=level;
  end;
end;procedure TForm1.Table1NewRecord(DataSet: TDataSet);
begin
  setFieldMask;
end;procedure TForm1.Table1BeforeEdit(DataSet: TDataSet);
begin
  setFieldMask;
end;procedure TForm1.Table1AfterDelete(DataSet: TDataSet);
begin
  UpdateTree(gNode,'','del'); 
end;procedure TForm1.Table1AfterInsert(DataSet: TDataSet);
begin
  mystate:='add';
end;procedure TForm1.Table1AfterPost(DataSet: TDataSet);
var
  nodetext:string;
begin
  nodetext:=table1.fieldbyName('dwbm').Text+'-'+table1.fieldByName('dwmc').Text;
  if mystate='add' then
    UpdateTree(gNode,nodetext,mystate);
  if mystate='edi' then
    UpdateTree(gNode,nodetext,mystate);  mystate:='edi';
  table1.Refresh;
end;procedure TForm1.Table1AfterEdit(DataSet: TDataSet);
begin
  mystate:='edi';
end;procedure TForm1.Table1BeforeDelete(DataSet: TDataSet);
begin
  if Application.MessageBox('确定要删除？','操作提示',
    MB_OKCANCEL)<>IDOK then table1.cancel;
end;procedure TForm1.FormCreate(Sender: TObject);
begin
  table1.DatabaseName:='C:\My Documents\treeview';
  LoadTree(table1);
end;procedure TForm1.treeClick(Sender: TObject);
var
  temp,recID:string;
  n,m:integer;
  curLevel:integer;begin
  gNode:=tree.Selected;
  n:=Pos('-',gNode.text)-1;
  recID:=copy(gNode.text,1,n);
  gNodeID:=recID;
  if gNode.text<>'单位字典' then
  begin
    if recID<>'' then
    begin
      with table1 do
      begin
        open;
        active:=true;
        FindNearest([recID]);
      end;
      curLevel:=getNodeLevel(cTreeCodeFormat,recID)+1;
    end
    else
      curLevel:=1;
  end;
  gNodelevel:=curLevel;
end;end.

Answer 5

另外就是拖动节点的问题
tv.DragMode:=dmAutomaticprocedure TTreeV.tvStartDrag(Sender: TObject;
  var DragObject: TDragObject);
begin
  nodeText:=tv.Selected.Text;
end;procedure TTreeV.tvEndDrag(Sender, Target: TObject; X, Y: Integer);
begin
  Cursor:=crDefault;
  try
    tv.Selected.MoveTo(tv.GetNodeAt(X,Y),naInsert);
    tv.GetNodeAt(X,Y).MoveTo(tv.Selected,naInsert);
  except
    showmessage('out of range');
  end;
end;procedure TTreeV.tvDragDrop(Sender, Source: TObject; X, Y: Integer);
begin
  Cursor:=crDrag;
end;procedure TTreeV.tvDragOver(Sender, Source: TObject; X, Y: Integer;
  State: TDragState; var Accept: Boolean);
begin
  Accept:=True;
end;