关于delphi treeview加选择框
大家好！前面看了万一老师的博客，用
SetWindowLong(H, GWL_STYLE, GetWindowLong(H, GWL_STYLE) or TVS_CHECKBOXES)
实现在treeview前加选择框。试了一下，可以，不过我有一个疑问，如何用代码控制将某个节点置为“选中”或“未选中”状态呢？我的目的是想，在某个节点状态改变（选中或未选中）时，自动改变父节点和子节点的状态。
谢谢！


[解决办法]
把treeview和imagelist结合起来使用，很方便的就可以达到楼主想要的效果。
[解决办法]
就是修改TreeView的StateIndex来改变选中未选中，ImageList中添加2个图标，一个是不打勾的，一个打勾的，然后改StateIndex就可以
[解决办法]
1stClass 里面有这样的组件
[解决办法]
曾经写过的一个控件

Delphi(Pascal) code

unit CheckedTreeView;interfaceuses  Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,  ComCtrls, Commctrl;type  TTVCheckChangedEvent = procedure(Sender: TObject; Node: TTreeNode; Checked: boolean) of object;  TCheckedTreeView = class(TTreeView)  private    { Private declarations }  protected    { Protected declarations }    F_OnNodeCheckChanged: TTVCheckChangedEvent;  //当一个Node的Checked属性发生变化后触发    F_CheckedNodeList: TList;               //纪录所有被Checked的节点    F_CheckBoxes: Boolean;                  //是否显示CheckBox    //某个Node被选中或反选后触发    procedure Do_NodeChecked(node: TTreeNode; checked: Boolean);virtual;    procedure CNNotify(var Message: TWMNotify); message CN_NOTIFY;    procedure SetCheckBoxes(value: Boolean);    function GetNodeFromItem(const Item: TTVItem): TTreeNode;    procedure Delete(Node: TTreeNode); override;  public    { Public declarations }    constructor Create(AOwner: TComponent); override;    destructor Destroy; override;    function NodeChecked(node: TTreeNode): boolean;    procedure CheckNode(Node :TTreeNode; Checked :Boolean);  published    { Published declarations }    property OnNodeCheckedChanged: TTVCheckChangedEvent read F_OnNodeCheckChanged write F_OnNodeCheckChanged;    property CheckBoxes: boolean read F_CheckBoxes write SetCheckBoxes;  end;function IsNodeChecked(node: TTreeNode): boolean;procedure SetNodeChecked(Node :TTreeNode; Checked :Boolean);procedure Register;implementationconst      TVIS_CHECKED = $2000;      TVIS_UNCHECKED = $1000;      TVS_CHECKBOXES = $0100;procedure Register;begin  RegisterComponents('Samples', [TCheckedTreeView]);end;procedure SetComCtlStyle(Ctl: TWinControl; Value: Integer; UseStyle: Boolean);var  Style: Integer;begin    if Ctl.HandleAllocated  then    begin        Style := GetWindowLong(Ctl.Handle, GWL_STYLE);        if   not   UseStyle   then            Style := Style and (not Value)        else            Style := Style or Value;        SetWindowLong(Ctl.Handle, GWL_STYLE, Style);    end;end;function IsNodeChecked(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;procedure SetNodeChecked(Node :TTreeNode; Checked :Boolean);var    TvItem:TTVItem;begin    FillChar(TvItem,   SizeOf(TvItem),   0);    with TvItem do    begin        hItem :=Node.ItemId;        Mask := TVIF_STATE;        StateMask := TVIS_STATEIMAGEMASK;        if Checked  then            TvItem.State:= (TvItem.State and (not TVIS_UNCHECKED)) or TVIS_CHECKED        else            TvItem.State:=(TvItem.State and (not TVIS_CHECKED)) or TVIS_UNCHECKED;        TreeView_SetItem(Node.TreeView.Handle, TvItem);    end;end;{ TCheckedTreeView }procedure TCheckedTreeView.CNNotify(var Message: TWMNotify);var    bOriginalChecked: Boolean;    bCurrentChecked: Boolean;    nIndex: Integer;    node: TTreeNode;begin    inherited;    With Message do    begin        case NMHdr^.code of            TVN_GETDISPINFO:            begin                with PTVDispInfo(NMHdr)^ do                begin                    Node := GetNodeFromItem(item);                    bCurrentChecked:= IsNodeChecked(node);                    nIndex:= F_CheckedNodeList.IndexOf(node);                    if nIndex >= 0 then                        bOriginalChecked:= true                    else                        bOriginalChecked:= false;                    if bOriginalChecked <> bCurrentChecked then                    begin                        if bCurrentChecked then                            F_CheckedNodeList.Add(node)                        else                            F_CheckedNodeList.Delete(nIndex);                        Do_NodeChecked(node, bCurrentChecked);                    end ;                end ;            end;        end ; //case    end;end ;constructor TCheckedTreeView.Create(AOwner: TComponent);begin  inherited;  F_CheckBoxes:= false;  F_CheckedNodeList:= TList.Create;end;destructor TCheckedTreeView.Destroy;begin  F_CheckedNodeList.Clear;  F_CheckedNodeList.Free;  inherited;end;function TCheckedTreeView.NodeChecked(node: TTreeNode): boolean;begin    Result:= IsNodeChecked(node);end ;procedure TCheckedTreeView.CheckNode(Node :TTreeNode; Checked :Boolean);var    nIndex: Integer;begin    SetNodeChecked(node, checked);    nIndex:= F_CheckedNodeList.IndexOf(node);    if checked and (nIndex< 0) then    begin        F_CheckedNodeList.Add(Node);        Do_NodeChecked(node, checked);    end    else if (not checked) and (nIndex>=0 ) then    begin        F_CheckedNodeList.Delete(nIndex);        Do_NodeChecked(node, checked);    end ;end ;procedure TCheckedTreeView.Do_NodeChecked(node: TTreeNode;  checked: Boolean);begin    if  F_CheckBoxes then        if Assigned(F_OnNodeCheckChanged) then            F_OnNodeCheckChanged(self,node, checked);end;function TCheckedTreeView.GetNodeFromItem(const Item: TTVItem): TTreeNode;begin  Result := nil;  if Items <> nil then    with Item do      if (state and TVIF_PARAM) <> 0 then Result := Pointer(lParam)      else Result := Items.GetNode(hItem);end;procedure TCheckedTreeView.SetCheckBoxes(value: Boolean);var    nIndex: Integer;    TvItem:TTVItem;begin    if Value<> F_CheckBoxes then    begin        F_CheckBoxes:= value;        if value then            SetComCtlStyle(Self,TVS_CHECKBOXES,True)        else        begin            SetComCtlStyle(Self,TVS_CHECKBOXES,False);            F_CheckedNodeList.Clear ;            //Update all nodes' state to remove the boxes            for nIndex := 0 to Items.Count -1 do            begin                FillChar(TvItem, SizeOf(TvItem),   0);                with TvItem do                begin                    hItem :=Items.Item[nIndex].ItemId;                    Mask := TVIF_STATE;                    StateMask := TVIS_STATEIMAGEMASK;                    TreeView_GetItem(Handle, TvItem);                    TVItem.State:= TVItem.state and (Not TVIS_UNCHECKED) and (Not TVIS_CHECKED);                    TreeView_SetItem(Handle, TvItem);                end;            end ;        end ;    end ;end ;procedure TCheckedTreeView.Delete(Node: TTreeNode);var    nIndex: Integer;begin    nIndex:= F_CheckedNodeList.IndexOf(node);    if nIndex >= 0 then        F_CheckedNodeList.Delete(nIndex);    inherited;end;end.