如何使用delphi中的Treeview控键,急！！！！！

Question

我想利用Treeview来显示树型结构,使得可以任意增加、删除节点，并且选中节点就显示与该节点有关的内容。我是个初学者，请多多指教！！！

Answer 1

procedure tfrm_jyyj.showtree;
var node: TTreeNode;
begin
//生成基本树型
  TV_1.Items.Clear;
  TV_1.Items.Add(TV_1.TopItem, '工作职责');
  cds_select.Close;
  cds_select.CommandText := '(select * from t_jy_mkqd where mkbm in' +
    '(select mkbm from t_jy_qxqd where js in' +
    '(select js from t_jy_czryjs where yhm=''' + VU_RYBH + ''' and jgbh=''' + VU_JGBH + ''')) or sfzjd=''0'') order by mkbm';
  cds_select.Open;
  cds_pd.Close;
  cds_pd.CommandText := cds_select.CommandText;
  cds_pd.Open;
  DSSocketConnection1.Connected := false;
  cds_select.IndexFieldNames := 'mkbm';
  cds_select.Filtered := false;
  cds_select.Filter := 'sjmk is null or sjmk=''''';
  cds_select.Filtered := true;
  cds_select.First;
  while not cds_select.Eof do
  begin
    cds_pd.filtered := false;
    cds_pd.Filter := 'mkbm like ''' + cds_select.fieldbyname('mkbm').AsString + '%'' and sfzjd=''1''';
    cds_pd.Filtered := true;
    if cds_pd.RecordCount > 0 then
    begin
      node := TV_1.Items.AddChild(TV_1.TopItem, '[' + cds_select.fieldbyname('mkbm').AsString + ']' + cds_select.fieldbyname('mkmc').AsString);
      node := TV_1.Items.AddChild(node, ''); //使改节点有下一层
    end;
    cds_select.Next;
  end;
  TV_1.AutoExpand := true;
end;

Answer 2

procedure Tfrm_jyyj.tv_1Expanding(Sender: TObject; Node: TTreeNode;
  var AllowExpansion: Boolean);
var node1: ttreenode;
begin
 //树型展开查询
  if (Node.getFirstChild.Text = '') then //判断改节点第一个子项是否为空字符
  begin
    Node.DeleteChildren; //删除该子项
    cds_select.filtered := false;
    cds_select.Filter := 'sjmk =''' + fI_getjg(node.Text) + '''';
    cds_select.filtered := true;
    while not cds_select.Eof do
    begin
      cds_pd.filtered := false;
      cds_pd.Filter := 'mkbm like ''' + cds_select.fieldbyname('mkbm').AsString + '%'' and sfzjd=''1''';
      cds_pd.Filtered := true;
      if cds_pd.RecordCount > 0 then
      begin
        node1 := TV_1.Items.AddChild(node, '[' + cds_select.fieldbyname('mkbm').AsString + ']' + cds_select.fieldbyname('mkmc').AsString);
        if cds_select.FieldByName('sfzjd').AsString <> '1' then //判断改节点是否有子项
          TV_1.Items.AddChild(node1, '');
      end;
      cds_select.Next;
    end;
  end;end;

Answer 3

create table treedb
(
   id char(6) primery key,
   text char(32)
)//该构件的功能是建立从数据库内建立三级树，子叶可以从另外的数据库中显示详细项
//要求主数据库的索引字段为6byte,ABC结构
unit newdBTV;interfaceuses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  ComCtrls,dbtables,db;type
  TNewDBTV = class(TTreeView)
  private
    { Private declarations }
    FtvStr: TStringList;
    Fselectstr:TStringList;
    Fchangeimage:boolean;
    FActive:           boolean;//激活
    FBytes:            integer;//每层占用关键字串的字节数
    FMastDataSource:          TDataSource; //SQL
    FDetailDataSource:          TDataSource; //SQL
    procedure ActiveTree(InVal: boolean);
    procedure setByte(InVal: integer);
    function  CreateTree:boolean; //建立树
    procedure SetMastDataSource(Value: TDataSource);
    procedure SetDetailDataSource(Value: TDataSource);
  protected
    procedure Click;override;
  public
    constructor Create(AOwner: TComponent);override;
    destructor  Destroy;override;
    procedure editNode(DispStr,KeyStr:string);//修改当前节点
    procedure  delNode;//删除当前节点
    function  GetNodeKeyStr(tn:TTreeNode):string;//得到当前节点的键值
    function  AddNode(tn:TTreeNode;DispStr,KeyStr:string):TTreeNode;//加子节点
    procedure ClearTree;//清除树
  published
    property Active:boolean          read FActive
                                    write ActiveTree;
    property Bytes:integer           read FBytes
                                    write SetByte;
    property MastDataSource:TDataSource        read FMastDataSource
                                    write SetMastDataSource;
    //sql语句中,规定第0个field为键值,第1个field为显示字段,
    //第2个field为键值长度
    property DetailDataSource:TDataSource        read FDetailDataSource
                                    write setDetailDataSource;
    //sql语句中,规定第0个field为键值,第1个field为显示字段,
    //第2个field为连接字段
    property changeimage:boolean read Fchangeimage write Fchangeimage;  end;procedure Register;implementationprocedure Register;
begin
  RegisterComponents('Samples', [TNewDBTv]);
end;
constructor TNewdbTV.Create(AOwner: TComponent);
begin
  inherited Create(AOwner);
  Fchangeimage:=false;
  readonly:=true;
  self.HideSelection:=false;
  FActive:=false;
  FBytes:=0;
  FtvStr:=TStringList.create;
  Fselectstr:=TStringList.create;
end;destructor  TNewdbTV.Destroy;
begin
  FtvStr.free;
  Fselectstr.free;
  FMastDataSource:=nil;
  FDetailDataSource:=nil;
  inherited Destroy;
end;function TNewdbTV.GetNodeKeyStr(tn:TTreeNode):string;//得到节点的键值
begin
  if tn.AbsoluteIndex<>-1 then result:=FtvStr[tn.AbsoluteIndex]
  else result:='';
end;function TNewdbTV.AddNode(tn:TTreeNode;DispStr,KeyStr:string):TTreeNode;//加节点
begin
  if tn=nil then
    Result:=Items.Add(tn,DispStr)
  else
    Result:=Items.AddChild(tn,DispStr);
  FtvStr.insert(result.AbsoluteIndex,KeyStr);//影射树
  if Fbytes=0 then
    Fselectstr.insert(result.AbsoluteIndex,'1')
  else
    Fselectstr.insert(result.AbsoluteIndex,'0');
  Result.ImageIndex:=Result.Level+1; //boot
  if Fchangeimage then Result.selectedIndex:=Result.ImageIndex;
end;procedure TNewdbTv.editNode(DispStr,KeyStr:string);//修改当前节点
var i:integer;
    s1,s2:string;
begin
   if selected=nil then exit;
   selected.Text:=DispStr;
   s1:=FtvStr.strings[selected.AbsoluteIndex];
   FtvStr.strings[selected.AbsoluteIndex]:=keystr;
   if FBytes=0 then exit;
   if FDetailDataSource<>nil then exit;
   //修改其子节点得代码
   for i:=selected.AbsoluteIndex+1 to FtvStr.Count-1 do
     begin
       s2:=FtvStr.strings[i];
       if s1=copy(s2,1,length(s1)) then
          FtvStr.strings[i]:=keystr+copy(s2,length(s1)+1,length(s2))
       else
         break;
     end;
end;
procedure  TNewdbTv.delNode;//删除当前节点
var s,s1:string;
    i:integer;
begin
   if selected=nil then exit;
   i:=selected.AbsoluteIndex;
   s:=FtvStr.strings[selected.AbsoluteIndex];
   selected.Delete;
   if (FBytes=0)or(FdetailDatasource<>nil) then
     begin
       FtvStr.delete(i);
       FselectStr.delete(i);
       exit;
     end;
   //删除其子节点得代码
   while true do
     begin
       FtvStr.delete(i);
       FselectStr.delete(i);
       if i=FtvStr.count then break;
       s1:=copy(FtvStr.strings[i],1,length(s));
       if s1<>s then break;
       if FtvStr.strings[i]='' then break;
     end;
end;procedure TNewdbTV.ClearTree;//清除树
begin
  items.Clear;
  FselectStr.clear;
  FtvStr.Clear;
end;procedure TNewDBTv.ActiveTree(InVal: boolean);
begin
    FActive:=Inval;
    ClearTree;
    if Inval then
      begin //建立树
        if FMastDatasource=nil then
          begin
            FActive:=false;
            exit;
          end;
        if not CreateTree then
          begin //建立树
            ClearTree;
            FActive:=false;
            exit;
          end;
      end;
end;

Answer 4

procedure TNewDBTv.setmastDatasource(Value: TDatasource);
begin
   if FmastDatasource<>Value then
     begin
       FmastDatasource:=Value;
       ClearTree;
       FActive:=false;
     end;
end;
procedure TNewDBTv.setdetailDatasource(Value: TDatasource);
begin
   if FDetailDatasource<>Value then
     begin
       FDetailDatasource:=Value;
       ClearTree;
       FActive:=false;
     end;
end;
procedure TNewDBTv.setByte(InVal: integer);
begin //设置树的分层方法,即每层所占关键串的字节数,隐含为2
  ClearTree;//清除树
  FActive:=false;
  if InVal>0 then FBytes:=InVal
  else FBytes:=0;
end;function TNewDBTv.CreateTree:boolean; //建立树
var root:ttreenode;
begin
   result:=false;
   if FMastDatasource.dataset=nil then
       begin
         messagebox(application.handle,pchar('主表数据集不存在!'),'警告',0);
         exit;
       end;
   if FMastDatasource.dataset.active=false then
   try
     FMastDatasource.dataset.Open;
   except
     on e:exception do
       begin
         messagebox(application.handle,pchar('主表打开失败!'+e.message),'警告',0);
         exit;
       end;
   end;
   FmastDatasource.dataset.first;
   if Fmastdatasource.dataset.FieldCount<3 then
     begin
        messagebox(application.handle,'主表字段数不能小于3!','警告',0);
        exit;
     end;
   if FmastDatasource.dataset.isempty then
     begin
       result:=true;
       exit;
     end;
   if FdetailDatasource<>nil then
     begin
       if FdetailDatasource.dataset=nil then
         begin
           messagebox(application.handle,pchar('子表数据集不存在!'),'警告',0);
           exit;
         end;
       if FDetailDataSource.dataset.active=false then
       try
         FdetailDataSource.dataset.Open;
       except
         on e:exception do
           begin
             messagebox(application.handle,pchar('子表打开失败!'+e.message),'警告',0);
             exit;
           end;
       end;
       if FDetailDatasource.dataset.FieldCount<3 then
         begin
           messagebox(application.handle,'子表字段数不能小于3!','警告',0);
           exit;
         end;
       FDetailDatasource.dataset.first;
     end;
   FmastDatasource.dataset.filter:=FmastDatasource.dataset.fields[2].fieldname+'='+trim(FmastDatasource.dataset.fields[2].asstring);
   if Fbytes<>0 then FmastDatasource.dataset.filtered:=true;
   items.BeginUpdate;
   root:=AddNode(nil,trim(FmastDatasource.dataset.fields[1].asString),trim(FmastDatasource.dataset.fields[0].asString));
   FmastDatasource.dataset.Next;
   while not(FmastDatasource.dataset.eof) do
     begin
       AddNode(nil,trim(FmastDatasource.dataset.fields[1].asString),trim(FmastDatasource.dataset.fields[0].asString));
       FmastDatasource.dataset.Next;
     end;
   selected:=root;
   click;
   if not root.Expanded then root.Expand(false);
   items.EndUpdate;
   Result:=true;
end;
//加当前节点得下级节点
procedure TNewdbtv.Click;
var node:ttreenode;
    i:integer;
    s:string;
begin
  inherited;
  if FActive=false then exit;
  if selected=nil then exit;
  if fselectstr[selected.AbsoluteIndex]='1' then exit;
  FmastDatasource.dataset.filtered:=false;
  FmastDatasource.dataset.filter:=
      FmastDatasource.dataset.fields[2].fieldname+'='+inttostr(length(ftvstr[selected.AbsoluteIndex])+Fbytes);
  i:=length(ftvstr[selected.AbsoluteIndex]);
  s:=ftvstr[selected.AbsoluteIndex];
  FmastDatasource.dataset.filtered:=true;
  while not FmastDatasource.dataset.eof do
    begin
      if copy(FmastDatasource.dataset.fields[0].asString,1,i)=s then
        AddNode(selected,trim(FmastDatasource.dataset.fields[1].asString),trim(FmastDatasource.dataset.fields[0].asString));
      FmastDatasource.dataset.Next;
    end;
  fselectstr[selected.AbsoluteIndex]:='1';
  if (Fdetaildatasource<>nil)and(ftvstr[selected.AbsoluteIndex]<>'') then
  if length(ftvstr[selected.AbsoluteIndex])=length(trim(FdetailDatasource.dataset.Fields[2].AsString)) then
    begin
      FdetailDatasource.dataset.filtered:=false;
      FdetailDatasource.dataset.Filter:=FdetailDatasource.dataset.fields[2].fieldname+'='''+ftvstr[selected.AbsoluteIndex]+'''';
      FdetailDatasource.dataset.Filtered:=true;
      while not FdetailDatasource.dataset.eof do
        begin
          node:=AddNode(selected,trim(FdetailDatasource.dataset.fields[1].asString),trim(FdetailDatasource.dataset.fields[0].asString));
          fselectstr[node.AbsoluteIndex]:='1';
          FdetailDatasource.dataset.Next;
        end;
    end;
end;end.

Answer 5

//读表展开树
   ADOTable1.Active :=true;
   ADOTable2.Active :=true;
   ADOTable3.Active :=true;   //一级树
   with ADOTable1 do
   begin
     first;
     while not ADOTable1.Eof do
     begin
       s:=Fieldbyname('kind1').asstring;
       i:=Fieldbyname('kind1id').asfloat;
       MyTreeNode1:=TreeView1.Items.Add(nil,s);
       //二级树
       with ADOTable2 do
       begin
         Filter:='kind1id=' + floattostr(i);
         Filtered:=true;
         First;
         while not ADOTable2.Eof do
         begin
           s:=Fieldbyname('kind2').asstring;
           i:=Fieldbyname('kind2id').asfloat;
           MyTreeNode2:=TreeView1.Items.AddChild(MyTreeNode1,s);
           //三级树
           with ADOTable3 do
           begin
             Filter:='kind2id=' + floattostr(i);
             Filtered:=true;
             First;
             while not ADOTable3.Eof do
             begin
               s:=Fieldbyname('kind3').asstring;
               TreeView1.Items.Addchild(MyTreeNode2,s);
               next;
             end;
           end;
         next;
         end;
       end;
       next;
     end;
   end; 

Answer 6

树形显示结构可以随数据库更新而自动更新
unit Unit1;interfaceuses
  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
  StdCtrls, Grids, DBGridEh, fcTreeView, ExtCtrls, DBCtrls, Db, ADODB,
  fcdbtreeview, Buttons;type
  TForm1 = class(TForm)
    DBGridEh1: TDBGridEh;
    DBGridEh2: TDBGridEh;
    Label1: TLabel;
    Label2: TLabel;
    ADOQuery1: TADOQuery;
    ADOQuery2: TADOQuery;
    DataSource1: TDataSource;
    DataSource2: TDataSource;
    ADOConnection1: TADOConnection;
    DBNavigator1: TDBNavigator;
    DBNavigator2: TDBNavigator;
    fcDBTreeView1: TfcDBTreeView;
    BitBtn1: TBitBtn;
    procedure FormShow(Sender: TObject);
    procedure BitBtn1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;var
  Form1: TForm1;implementation{$R *.DFM}procedure TForm1.FormShow(Sender: TObject);
begin
   Datasource1.DataSet:= ADOQuery1;
   Datasource2.DataSet:= ADOQuery2;   with fcDBTreeView1 do
   begin
      DatasourceFirst:= Datasource1;
      DatasourceLast:= Datasource2;
      DisplayFields.Add('Main名称：+#34+Name+#34');
      DisplayFields.Add('Detail名称：+#34+Name+#34');
   end;
   with ADOQuery1 do
   begin
      Close;
      SQL.Clear;
      SQL.Add(' select * from Main');
      Open;
   end;
   with ADOQuery2 do
   begin
      Close;
      SQL.Clear;
      SQL.Add(' select * from Detail');
      SQL.Add(' where ID=:ID');
      DataSource:= Datasource1;
      Open;
   end;
end;end.