Question

如何查看Windows资源管理器是否已使用特定路径打开？我不希望我的应用程序打开许多重复的窗口。我无法用这种方式做到这一点：

var
  H: hwnd;
begin
  if FileExists(edt8.Text) then
  begin
    H := FindWindow(0, PChar(ExtractFilePath(edt8.Text)));
    if H <> 0 then
      ShowMessage('explorer already opened')//explorer bring to front
    else
      ShellExecute(Application.Handle, nil, 'explorer.exe',
        PChar(ExtractFilePath(edt8.Text)), nil, SW_NORMAL);
  end;
end;

Answer 1

IShellWindows :: FindWindowSW方法

有一个很好的方法FindWindowSW应该找到一个现有的Shell窗口，其中包括Windows资源管理器窗口，我要说。所以，希望我能够轻松地找到一个现有的窗口，我写了这段代码：

uses
  ActiveX, ShlObj, SHDocVw, ComObj;

function IDListFromPath(const Path: WideString): PItemIDList;
var
  Count: ULONG;
  Attributes: ULONG;
  ShellFolder: IShellFolder;
begin
  OleCheck(SHGetDesktopFolder(ShellFolder));
  OleCheck(ShellFolder.ParseDisplayName(0, nil, PWideChar(Path), Count, Result, Attributes));
end;

function GetExplorerHandle(const Path: WideString): HWND;
var
  IDList: PItemIDList;
  Unused: OleVariant;
  Location: OleVariant;
  ShellWindows: IShellWindows;
begin
  OleCheck(CoCreateInstance(CLASS_ShellWindows, nil, CLSCTX_LOCAL_SERVER, IID_IShellWindows, ShellWindows));
  Unused := Unassigned;
  IDList := IDListFromPath(Path);
  PVariantArg(@Location).vt := VT_VARIANT or VT_BYREF;
  PVariantArg(@Location).pvarVal := PVariant(IDList);
  ShellWindows.FindWindowSW(Location, Unused, SWC_EXPLORER, Integer(Result), SWFO_INCLUDEPENDING);
end;

但它从未找到具有给定文件夹路径的Windows资源管理器窗口（它始终返回0）。我使用SWC_EXPLORER类只搜索Windows资源管理器窗口，构建绝对ID列表，使用了正确的 VT_VARIANT |位置的VT_BYREF 变体（至少我希望如此，如果没有，请告诉我）。我还尝试通过包含 SWFO_NEEDDISPATCH 选项返回IDispatch（方法始终返回nil引用）。所以我放弃了这种方法（没有找到任何例子）。

IShellWindows枚举

以下代码的灵感来自this article和this example。这是一个计划：

1. IShellWindows.Item(n)
2. ⤷ IDispatch.QueryInterface(IWebBrowserApp)
3.   ⤷ IWebBrowserApp.QueryInterface(IServiceProvider)
4.     ⤷ IServiceProvider.QueryService(STopLevelBrowser, IShellBrowser)
5.       ⤷ IShellBrowser.QueryActiveShellView
6.         ⤷ IShellView.QueryInterface(IFolderView)
7.           ⤷ IFolderView.GetFolder(IPersistFolder2)
8.             ⤷ IPersistFolder2.GetCurFolder
9.               ⤷ ITEMIDLIST

还有一些描述：

首先，您获取IShellWindows接口参考并迭代其项目。
对于每个项目，IShellWindows界面返回窗口的IDispatch界面，然后您可以查询 IWebBrowserApp 界面参考。
获取的 IWebBrowserApp 界面（文档参考IWebBrowser2，因为它的实现）除了其他人之外还提供了有关主机窗口的信息，比如句柄这可以在以后用于将窗口带到前台。我们需要更深入。因此，让我们查询IServiceProvider接口的此接口参考（它是获取给定服务接口的访问器）。
现在，从最顶层的浏览器实施服务查询其IShellBrowser界面。对于我们的目标，这个界面的参考仍然没有意义。
获取显示的Shell视图对象的IShellBrowser查询。
现在我们终于可以说，如果迭代的Shell窗口不是Internet Explorer窗口。到目前为止，他们已经实现了通用接口。现在，如果我们查询获得的IShellView IFolderView接口并且成功，则它不是Internet Explorer，我们可以继续。
查询当前显示的文件夹对象的IFolderView界面的获取IPersistFolder2参考。
如果我们在那里成功并获得了IPersistFolder2引用，那么让我们获取当前文件夹对象的ITEMIDLIST。
如果我们成功完成了最后一步，我们有ITEMIDLIST当前显示的Windows资源管理器实例文件夹（或相同的接口实现者），我们最终可以检查是否获得了{{ 3}}等于我们为输入路径解析的那个。如果是这样，将该窗口置于前台，如果不是，则继续下一次迭代。

这是一个Delphi代码。我不知道你的Delphi版本需要多少;这是D2009所需的最低限度（从Windows SDK 10.0.15063.0手动翻译）。这不是最好的例子;在实际代码中，您可能更喜欢将其包装到一个类中，并且具有更灵活的界面，但这取决于您的设计偏好。最后，如果您的Delphi比2009年更新，您可能不需要导入的原型，如果年纪较大，您可能会遗漏一些：

uses
  ActiveX, ShlObj, SHDocVw, ComObj;

{ because of Win32Check }
{$WARN SYMBOL_PLATFORM OFF}
const
  IID_IFolderView: TGUID = '{CDE725B0-CCC9-4519-917E-325D72FAB4CE}';
  IID_IPersistFolder2: TGUID = '{1AC3D9F0-175C-11D1-95BE-00609797EA4F}';
  IID_IServiceProvider: TGUID = '{6D5140C1-7436-11CE-8034-00AA006009FA}';
  SID_STopLevelBrowser: TGUID = '{4C96BE40-915C-11CF-99D3-00AA004AE837}';

type
  IFolderView = interface(IUnknown)
  ['{CDE725B0-CCC9-4519-917E-325D72FAB4CE}']
    function GetCurrentViewMode(out pViewMode: UINT): HRESULT; stdcall;
    function SetCurrentViewMode(ViewMode: UINT): HRESULT; stdcall;
    function GetFolder(const riid: TIID; out ppv): HRESULT; stdcall;
    function Item(iItemIndex: Integer; out ppidl: PItemIDList): HRESULT; stdcall;
    function ItemCount(uFlags: UINT; out pcItems: Integer): HRESULT; stdcall;
    function Items(uFlags: UINT; const riid: TIID; out ppv): HRESULT; stdcall;
    function GetSelectionMarkedItem(out piItem: Integer): HRESULT; stdcall;
    function GetFocusedItem(out piItem: Integer): HRESULT; stdcall;
    function GetItemPosition(pidl: PItemIDList; out ppt: TPoint): HRESULT; stdcall;
    function GetSpacing(var ppt: TPoint): HRESULT; stdcall;
    function GetDefaultSpacing(out ppt: TPoint): HRESULT; stdcall;
    function GetAutoArrange: HRESULT; stdcall;
    function SelectItem(iItem: Integer; dwFlags: DWORD): HRESULT; stdcall;
    function SelectAndPositionItems(cidl: UINT; var apidl: PItemIDList; var apt: TPoint; dwFlags: DWORD): HRESULT; stdcall;
  end;

  EShObjectNotFolder = class(Exception);

function ILGetSize(pidl: PItemIDList): UINT; stdcall;
  external 'shell32.dll' name 'ILGetSize';
function ILIsEqual(pidl1: PItemIDList; pidl2: PItemIDList): BOOL; stdcall;
  external 'shell32.dll' name 'ILIsEqual';
function InitVariantFromBuffer(pv: Pointer; cb: UINT; out pvar: OleVariant): HRESULT; stdcall;
  external 'propsys.dll' name 'InitVariantFromBuffer';
function CoAllowSetForegroundWindow(pUnk: IUnknown; lpvReserved: Pointer): HRESULT; stdcall;
  external 'ole32.dll' name 'CoAllowSetForegroundWindow';

resourcestring
  rsObjectNotFolder = 'Object "%s" is not a folder.';

{ this parses the input folder path and creates ITEMIDLIST structure if the given
  folder path is a valid absolute path to an existing folder }
function GetFolderIDList(const Folder: string): PItemIDList;
const
  SFGAO_STREAM = $00400000;
var
  Count: ULONG;
  Attributes: ULONG;
  ShellFolder: IShellFolder;
begin
  OleCheck(SHGetDesktopFolder(ShellFolder));
  Attributes := SFGAO_FOLDER or SFGAO_STREAM;
  OleCheck(ShellFolder.ParseDisplayName(0, nil, PWideChar(WideString(Folder)), Count, Result, Attributes));
  if not ((Attributes and SFGAO_FOLDER = SFGAO_FOLDER) and (Attributes and SFGAO_STREAM <> SFGAO_STREAM)) then
  begin
    CoTaskMemFree(Result);
    raise EShObjectNotFolder.CreateFmt(rsObjectNotFolder, [Folder]);
  end;
end;

{ translated from the link mentioned in this comment; D2009 does not allow me to
  create an OleVariant of type VT_ARRAY|VT_UI1 which is needed for the Navigate2
  method so I've imported and used the InitVariantFromBuffer function here
  https://msdn.microsoft.com/en-us/library/windows/desktop/gg314982(v=vs.85).aspx }
procedure OpenNewExplorer(IDList: PItemIDList);
var
  Location: OleVariant;
  WebBrowser: IWebBrowser2;
begin
  OleCheck(CoCreateInstance(CLASS_ShellBrowserWindow, nil, CLSCTX_LOCAL_SERVER, IID_IWebBrowser2, WebBrowser));
  OleCheck(CoAllowSetForegroundWindow(WebBrowser, nil));
  OleCheck(InitVariantFromBuffer(IDList, ILGetSize(IDList), Location));
  try
    WebBrowser.Navigate2(Location, Unassigned, Unassigned, Unassigned, Unassigned);
  finally
    VariantClear(Location);
  end;
  WebBrowser.Visible := True;
end;

{ translated from the link mentioned in this comment
  https://blogs.msdn.microsoft.com/oldnewthing/20040720-00/?p=38393 }
procedure BrowseInExplorer(const Folder: string);
var
  I: Integer;
  WndIface: IDispatch;
  ShellView: IShellView;
  FolderView: IFolderView;
  SrcFolderID: PItemIDList;
  CurFolderID: PItemIDList;
  ShellBrowser: IShellBrowser;
  ShellWindows: IShellWindows;
  WebBrowserApp: IWebBrowserApp;
  PersistFolder: IPersistFolder2;
  ServiceProvider: IServiceProvider;
begin
  SrcFolderID := GetFolderIDList(Folder);
  try
    OleCheck(CoCreateInstance(CLASS_ShellWindows, nil, CLSCTX_LOCAL_SERVER, IID_IShellWindows, ShellWindows));
    { iterate all Shell windows }
    for I := 0 to ShellWindows.Count - 1 do
    begin
      WndIface := ShellWindows.Item(VarAsType(I, VT_I4));
      { do not use OleCheck here; windows like Internet Explorer do not implement
        all the interfaces; it is the way to distinguish Windows Explorer windows
        actually; so let's get all the references and if we succeed, check if the
        obtained folder equals to the passed one; if so, bring that window to top
        and exit this procedure }
      if Assigned(WndIface) and
        Succeeded(WndIface.QueryInterface(IID_IWebBrowserApp, WebBrowserApp)) and
        Succeeded(WebBrowserApp.QueryInterface(IID_IServiceProvider, ServiceProvider)) and
        Succeeded(ServiceProvider.QueryService(SID_STopLevelBrowser, IID_IShellBrowser, ShellBrowser)) and
        Succeeded(ShellBrowser.QueryActiveShellView(ShellView)) and
        Succeeded(ShellView.QueryInterface(IID_IFolderView, FolderView)) and
        Succeeded(FolderView.GetFolder(IID_IPersistFolder2, PersistFolder)) and
        Succeeded(PersistFolder.GetCurFolder(CurFolderID)) and
        ILIsEqual(SrcFolderID, CurFolderID) then
      begin
        { restore the window if minimized, try to bring it to front and exit this
          procedure }
        if IsIconic(WebBrowserApp.HWnd) then
          Win32Check(ShowWindow(WebBrowserApp.HWnd, SW_RESTORE));
        {$IFNDEF IBelieveThatIWebBrowserAppVisiblePropertyBringsWindowToFront}
        Win32Check(SetForegroundWindow(WebBrowserApp.HWnd));
        {$ELSE}
        OleCheck(CoAllowSetForegroundWindow(WebBrowserApp, nil));
        WebBrowserApp.Visible := True;
        {$ENDIF}
        Exit;
      end;
    end;
    { the procedure was not exited, hence an existing window was not found, so go
      and open the new one }
    OpenNewExplorer(SrcFolderID);
  finally
    CoTaskMemFree(SrcFolderID);
  end;
end;
{$WARN SYMBOL_PLATFORM ON}

可能的用法：

BrowseInExplorer('C:\MyFolder');

检查Windows资源管理器是否已在给定路径上打开

1 个答案:

IShellWindows :: FindWindowSW方法

IShellWindows枚举