Delphi实现树型结构具体实例

无需你的理解 發表於 2013-10-19 15:54:17

<div class="codetitle">复制代码 代码如下:</div><div class="codebody" id="code39713"> unit Unit1; interface uses   Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,   Dialogs, StdCtrls, ComCtrls, DB, ADODB; type   PNodeInfoEx = ^TNodeInfoEx;   TNodeInfoEx = Packed Record       NodeID    : Integer;       ParentID  : Integer;       NodeType  : Integer;       ChnNodeTitle : String;       ImageIndex: SmallInt;       SelectedIndex: SmallInt;    end;   TForm1 = class(TForm)     tv1: TTreeView;     btn1: TButton;     qry1: TADOQuery;     procedure btn1Click(Sender: TObject);     procedure FormDestroy(Sender: TObject);   private     { Private declarations }     function StaticBuildTree(TreeView:TTreeView ):Boolean;     function AddTreeItem(TreeView:TTreeView; AddNodeInfo:PNodeInfoEx):TTreeNode;     function FindTreeItem(TreeView:TTreeView; CurNodeID:integer): TTreeNode;   public     { Public declarations }   end; var   Form1: TForm1; implementation {$R *.dfm} function TForm1.StaticBuildTree(TreeView:TTreeView ):Boolean; var   AddNodeInfo : PNodeInfoEx; begin   Result := False;   qry1.LoadFromFile('c:/AdminixTree.xml');//这里以XML文件做为数据源   Treeview.Items.BeginUpdate;//记住：在进行批量添加数据时要使用BeginUpdate,来暂时关闭由于添加数据而触发的某些事件(如OnChange事件等)   Treeview.Items.Clear;//清空Treeview   try     try       if qry1.RecordCount >0 then         begin           qry1.First;           while Not qry1.Eof do           begin             New(AddNodeInfo) ;//生成结构体             AddNodeInfo^.NodeID := qry1.FieldByName('NODE_ID').AsInteger;             AddNodeInfo^.ParentID := qry1.FieldByName('PARENT_ID').AsInteger;             AddNodeInfo^.NodeType := qry1.FieldByName('NodeType').AsInteger;             AddNodeInfo^.ChnNodeTitle := qry1.FieldByName('ChnNodeTitle').AsString;             AddNodeInfo^.ImageIndex := qry1.FieldByName('ImageIndex').AsInteger;             AddNodeInfo^.SelectedIndex := qry1.FieldByName('SelectedIndex').AsInteger;             AddTreeItem(Treeview,AddNodeInfo);//把结构体的指针存到Treeview中             qry1.Next;           end;         end;     except       Application.MessageBox('生成树结点失败',MB_ICONSTOP+MB_OK);       raise;//向上级抛异常     end;     qry1.Close;     Result := True;   finally     Treeview.Items.EndUpdate;   end; end; //在加入结点时，应先判断加入的是父结点还是子结点，判断的依据是在已存在的树结点中是否存在该结点的ParentID function TForm1.AddTreeItem(TreeView:TTreeView; AddNodeInfo:PNodeInfoEx):TTreeNode; var     ParentNode: TTreeNode; begin     ParentNode := FindTreeItem(Treeview,AddNodeInfo^.ParentID);     If ParentNode <> nil then         Result := Treeview.Items.AddChildObject(ParentNode, Trim(AddNodeInfo.ChnNodeTitle), Pointer(AddNodeInfo))     else         Result := Treeview.Items.AddObject(ParentNode, Trim(AddNodeInfo.ChnNodeTitle), Pointer(AddNodeInfo));     if Result<>nil then     begin         Result.ImageIndex    := AddNodeInfo.ImageIndex;         Result.SelectedIndex := AddNodeInfo.SelectedIndex;     end; end; //这里是判断是否存在其父结点 function TForm1.FindTreeItem(TreeView:TTreeView; CurNodeID:integer): TTreeNode; var     i : Integer; begin   Result := nil;   for i := 0 to Treeview.Items.Count-1 do   begin       if CurNodeID=PNodeInfoEx(Treeview.Items.Data)^.NodeID then       begin           Result := Treeview.Items;           Exit;       end;   end; end; //生成树结构 procedure TForm1.btn1Click(Sender: TObject); begin    StaticBuildTree (tv1) end; //在窗体释放时一定要把树结点中的结构体指针给释放掉，对于在Dispose时为什么要进行强制转型后释放，以前有专门的讲解，在此不在累述 procedure TForm1.FormDestroy(Sender: TObject); var     i : Integer; begin   for i := 0 to tv1.Items.Count-1 do   begin        Dispose( PNodeInfoEx(tv1.Items.Data)  )   end; end; end. </div>
<div class="codetitle">复制代码 代码如下:</div><div class="codebody" id="code31427"> //如何访问树结点？ procedure TForm1.tv1MouseDown(Sender: TObject; Button: TMouseButton;   Shift: TShiftState; X, Y: Integer); var   pNode:TTreeNode; begin   pNode:=tv1.GetNodeAt(x,y);   if (pNode<>nil) and  (Button=mbleft) then    ShowMessage(PNodeInfoEx(pNode.Data)^.ChnNodeTitle); end; </div>

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Delphi实现树型结构具体实例