How to change path of an existing Windows Explorer window? - delphi

Question

I have the handle of an opened Windows Explorer window.
How can I send a command to it in order to change the path from
example: m:\programs to d:\programs.
Till now I was using ShellExecute() but it opens a new window. This is not good (user experience).

Answer 1

The following BrowseToFolder function navigates the existing instance of a Windows Explorer of the given AHandle handle (if exists) to a AFolderPath folder (if exists). If you won't specify the second parameter, the topmost window should be taken to navigate (or at least the documentation claims that; reality seems to take the oldest existing window). The function returns True, if the navigation has been successful, False otherwise:
uses
ActiveX, ShlObj, ShellAPI, SHDocVw;
const
IID_IServiceProvider: TGUID = '{6D5140C1-7436-11CE-8034-00AA006009FA}';
SID_STopLevelBrowser: TGUID = '{4C96BE40-915C-11CF-99D3-00AA004AE837}';
function GetItemIDListFromPath(const AFolderPath: WideString): PItemIDList;
var
Count: ULONG;
Attributes: ULONG;
ShellFolder: IShellFolder;
begin
Result := nil;
if Succeeded(SHGetDesktopFolder(ShellFolder)) then
begin
Count := 0;
if Failed(ShellFolder.ParseDisplayName(0, nil, PWideChar(AFolderPath),
Count, Result, Attributes))
then
Result := nil;
end;
end;
function BrowseToFolder(const AFolderPath: WideString;
AHandle: HWND = HWND_TOPMOST): Boolean;
var
I: Integer;
WndIface: IDispatch;
ItemIDList: PItemIDList;
ShellBrowser: IShellBrowser;
ShellWindows: IShellWindows;
WebBrowserApp: IWebBrowserApp;
ServiceProvider: IServiceProvider;
begin
Result := False;
if Succeeded(CoCreateInstance(CLASS_ShellWindows, nil, CLSCTX_LOCAL_SERVER,
IID_IShellWindows, ShellWindows)) then
begin
for I := 0 to ShellWindows.Count - 1 do
begin
if (AHandle <> HWND_TOPMOST) then
WndIface := ShellWindows.Item(VarAsType(I, VT_I4))
else
WndIface := ShellWindows.Item(VarAsType(SWC_EXPLORER, VT_UI4));
if Succeeded(WndIface.QueryInterface(IID_IWebBrowserApp,
WebBrowserApp)) then
begin
if (AHandle = HWND_TOPMOST) or (WebBrowserApp.HWnd = AHandle) then
begin
if Succeeded(WebBrowserApp.QueryInterface(IID_IServiceProvider,
ServiceProvider)) then
begin
if Succeeded(ServiceProvider.QueryService(SID_STopLevelBrowser,
IID_IShellBrowser, ShellBrowser)) then
begin
ItemIDList := GetItemIDListFromPath(AFolderPath);
Result := Succeeded(ShellBrowser.BrowseObject(ItemIDList,
SBSP_SAMEBROWSER or SBSP_ABSOLUTE));
end;
end;
Break;
end;
end;
end;
end;
end;
Here is the example usage:
procedure TForm1.Button1Click(Sender: TObject);
var
ExplorerHandle: HWND;
begin
ExplorerHandle := 123456;
if not BrowseToFolder('c:\Windows\System32\', ExplorerHandle) then
ShowMessage('Navigation to a folder failed!')
else
ShowMessage('Navigation to a folder succeeded!');
end;
Here is a complete testing project and the blog post from which I've taken the inspiration.