FILEDLG.DLL: description
Overview
FILEDLG (FILEDLG.DLL) is a COM module by ERCC that supplies the Windows common dialog for file selection (COMDLG32.DLL) as an object to OLE/COM clients like Visual Basic Script (VBS). It can be used as an alternative to Microsoft's COM module COMDLG32.OCX.
The following excerpt shows the most important VBS instructions.
Set dlg = CreateObject("FileDlg.FileSelection")
dlg.DialogTitle = "Please choose a file"
dlg.ShowDialog
f = dlg.FileName
FILEDLG is a mere Unicode version for NT-based Windows (from Windows 2000 on). FILEDLG employs the API function GetOpenFileName in a basically similar way as COMDLG32.OCX, but the range of functionality is comparatively modest and targets only the selection of an existing file.
Methods and Properties
All object properties not necessary for the intended use are omitted, that is replaced by internal settings. So the following function parameters and flags are predefined:
Filter = *.* Flags = OFN_FILEMUSTEXIST + OFN_PATHMUSTEXIST + OFN_HIDEREADONLY + OFN_NOCHANGEDIR
The string lengths (nMaxFile etc.) are set to 256 characters.
FILEDLG.FileSelection has the following properties that match those of the COMDLG32.OCX module:
| DialogTitle | sets the dialog box title (IN) |
| InitDir | sets the initial file directory (IN) |
| FileName | returns the path and filename of a selected file (OUT) |
| FileTitle | returns just the name —without the path— of the selected file (OUT) |
The function call (method) to show the dialog is named different:
| ShowDialog | displays an OpenFile common dialog box |
FILEDLG.FileSelection has the following additional properties:
| FilePath | returns just the path of the selected file (OUT) |
| Error | returns an error code (OUT) |
The file's path is derived from FileName and the API function's value nFileOffset. A trailing backslash is included.
The error code is determined via API function CommDlgExtendedError if GetOpenFileName returns zero, so this may be the respective DWORD value. Cancelling the file selection does not define an error code.
Folder Selection
Furthermore FILEDLG features the Windows dialog for selecting a folder (Shell API, function SHBrowseForFolder etc.). While this dialog box is available as a COM object by default (SHELL32.DLL), FILEDLG simplifies the use in Visual Basic Script. Besides, there are practical reasons to combine the two selection dialogs.
Simple Example (VBS):
Set dlg = CreateObject("FileDlg.PathSelection")
dlg.ShowDialog
f = dlg.FolderName
FILEDLG.PathSelection has the following properties:
| DialogText | sets an additional dialog text, 1024 characters max. (IN) |
| InitDir | sets the initial directory (IN) |
| FolderName | returns the name of a selected folder (OUT) |
| Error | returns an error code (OUT) |
This object's purpose is the plain selection of a folder. So the functionality is basically restricted to items (paths) of the file-system. If InitDir is not defined (or in a way not function-compatible), the root object of the file-system is preset, e.g. "My Computer" or the like.
Error may attain one of two error values: 1 indicates that the Shell API function didn't return a result (which is typically the case when the selection was cancelled), 2 would indicate a problem with the internal processing of the directory selection (a theoretical case).
License, Notes
FILEDLG.DLL is provided as freeware and "as is" without any warranty or liability.
Download, Installation
The file 
filedlg.zip contains FILEDLG.DLL along with a descriptive text file.
For installation save FILEDLG.DLL to a directory of your choice and register the file as a COM module (see FILEDLG.TXT for more information).
