Author: Tomas Rutkauskas

I am using a function from the ShlObj unit to select a networked computer via a 
Computer Browser. The browser window is called with SHBrowseForFolder(BrowseInfo), 
the window displayed always seems to position itself in the lower right of the 
screen. Is it possible to programatically reposition the window to be centered on 
the screen?

Answer:

Yes, you provide a browse callback function for this task.

1   uses
2     ActiveX, ShlObj;
3   
4   function CenterVertical(const rect: TRect; h: Integer): Integer;
5   begin
6     Result := (rect.bottom + rect.top - h) div 2;
7   end;
8   
9   function CenterHorizontal(const rect: TRect; w: Integer): Integer;
10  begin
11    Result := (rect.right + rect.left - w) div 2;
12  end;
13  
14  function BrowserCallback(Wnd: HWND; uMsg: UINT; lParam, lpData: LPARAM): Integer
15    stdcall;
16  var
17    r1, r2: TRect;
18  begin
19    result := 0;
20    if uMsg = BFFM_INITIALIZED then
21    begin
22      GetWindowRect(wnd, r1);
23      r2 := Rect(0, 0, Screen.Width, Screen.Height);
24      MoveWindow(wnd, CenterHorizontal(r2, r1.Right - r1.left), CenterVertical(r2,
25        r1.Bottom - r1.Top),
26        r1.Right - r1.Left, r1.Bottom - r1.Top, false);
27    end;
28  end;
29  
30  procedure TForm1.Button1Click(Sender: TObject);
31  var
32    browseinfo: TBrowseInfo;
33    pidl: PItemIDList;
34    buf: array[0..MAX_PATH] of Char;
35  begin
36    fillchar(browseinfo, SizeOf(browseinfo), 0);
37    browseinfo.hwndOwner := Handle;
38    browseinfo.lpszTitle := 'Select directory';
39    browseinfo.ulFlags := BIF_RETURNONLYFSDIRS or BIF_NEWDIALOGSTYLE;
40    browseinfo.lpfn := BrowserCallback;
41    pidl := ShBrowseForFolder(browseinfo);
42    if Assigned(pidl) then
43    begin
44      ShGetPathfromIDList(pidl, buf);
45      ShowMessage(buf);
46      CoTaskMemFree(pidl);
47    end;
48  end;