给 TTreeView 添加复选框

 //1.引用单元
 uses Commctrl ;

 //2.定义私有过程
   procedure tvToggleCheckbox(TreeView: TTreeView;Node: TTreeNode;isclick:boolean =false);
   procedure SetChecked(Node: TTreeNode; Checked: Boolean);
   function IsChecked(Node: TTreeNode): Boolean; 

 //3.过程体代码
 //检查某个节点是否被 选中
 function TForm1.IsChecked(Node: TTreeNode): Boolean;
 var
   TvItem :TTVItem;
 begin
   TvItem.Mask := TVIF_STATE;
   TvItem.hItem := Node.ItemId;
   TreeView_GetItem(Node.TreeView.Handle, TvItem);
   Result := (TvItem.State and TVIS_CHECKED) = TVIS_CHECKED;
 end;
 //让 某个节点被 选中
 procedure TForm1.SetChecked(Node: TTreeNode; Checked: Boolean);
 var
 TvItem :TTVItem;
 begin
   FillChar(TvItem, SizeOf(TvItem), );
   with TvItem do
   begin
     hItem := Node.ItemId;
     Mask := TVIF_STATE;
     StateMask := TVIS_STATEIMAGEMASK;
     if Checked then
       TvItem.State :=TVIS_CHECKED
     else
       TvItem.State :=TVIS_CHECKED shr ;
     TreeView_SetItem(Node.TreeView.Handle, TvItem);
   end;
 end;
 // 对节点中所有 子节点 都 选中或 未选中 状态
 procedure TForm1.tvToggleCheckbox(TreeView: TTreeView;
 Node: TTreeNode ;isclick :boolean=false);
 var CurNode, ParentNode, GrandSonNode,sonNode: TTreeNode;
 flg1: boolean;
 begin
   CurNode :=node;
   with TreeView do
   begin
     if IsChecked(CurNode) then //
     begin
       sonNode := CurNode.GetFirstChild; //遍历子树,选中 则子节点 全部 为选中；
       while sonNode<>nil do
       begin
         SetChecked(sonNode, true);
         tvToggleCheckbox(TreeView,sonNode,true);
         sonNode := sonNode.GetNextSibling;
       end;
       ParentNode:= CurNode.Parent; //父；
       if ParentNode<>nil then
       begin
         if not isChecked(parentNode) then
         begin
           GrandSonNode := ParentNode.GetFirstChild; //遍历子树；
           flg1 := false;
           while GrandSonNode<>nil do
           begin
             if (not IsChecked(GrandSonNode)) then //true,有未选中
             flg1 := true;
             if flg1 then //已有、退出loop;
             GrandSonNode := nil
             else
             GrandSonNode := GrandSonNode.GetNextSibling;
           end;
           SetChecked(ParentNode, not flg1);
           tvToggleCheckbox(TreeView,ParentNode,false);
         end;
       end; // end parentNode 不等于空
     end
     else if not IsChecked(CurNode) then
     begin
       ParentNode := CurNode.Parent; //父；
       if ParentNode<>nil then
       begin
         if isChecked(parentNode) then
         begin
           SetChecked(ParentNode, false);
           tvToggleCheckbox(TreeView,ParentNode);
         end;
       end; //end parentnode
       if (isclick) then
       begin
         sonNode := CurNode.GetFirstChild; //遍历子树,未选中 则子节点 全部 为未选中；
         while sonNode<>nil do
         begin
           SetChecked(sonNode, false);
           tvToggleCheckbox(TreeView,sonNode,true);
           sonNode := sonNode.GetNextSibling;
         end;
       end;
     end;
   end;
 end;

 //4.点击连选处理
 procedure TForm1.TreeView1Click(Sender: TObject);
 var
   P:TPoint;
   treenode :TTreeNode;
 begin
   GetCursorPos(P);
   P := TreeView1.ScreenToClient(P);
   if (htOnStateIcon in TreeView1.GetHitTestInfoAt(P.X,P.Y)) then
   begin
     treenode := TreeView1.GetNodeAt(P.X,P.Y);
     tvToggleCheckbox(TreeView1,treenode ,true);
   end;
 end;

 //5.生成节点
 procedure TForm1.FormCreate(Sender: TObject);
 begin
   //仅仅这一句话就能让treeview 显示复选框
   SetWindowLong(TreeView1.Handle, GWL_STYLE, GetWindowLong(TreeView1.Handle, GWL_STYLE) or $);
 //  SetWindowLong(H, GWL_STYLE, GetWindowLong(H, GWL_STYLE) or TVS_CHECKBOXES);  //这名同上一个意思
   {下面的代码只是给 TreeView 添加内容}
   with TreeView1 do
   begin
      Align := alLeft;
      Items.Add(nil, 'AAA');
      Items.Add(nil, 'BBB');
      Items.Add(nil, 'CCC');
      Items.AddChild(Items[], '');
      Items.AddChild(Items[], '');
      Items.AddChild(Items[], '');
   end;
 end;

 //6.查看是否选中
 procedure TForm1.Button1Click(Sender: TObject);
 var
   Node: TTreeNode;
   TVI: TTVItem;
 begin
   for Node in TreeView1.Items do
   begin
     TVI.mask := TVIF_STATE;
     TVI.hItem := Node.ItemId;
     TreeView_GetItem(TreeView1.Handle, TVI);
     if TVI.state and $ = $ then
       ShowMessage(Node.Text);
   end;
 end;