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#156: The alternatives for TOpenDialog/TSaveDialog

Today I want to display how you may use the simple functions as alternative for TOpenDialog/TSaveDialog components.

Problem is that Borland incorrectly wrote those components and when Microsoft add some new extended features in own dialogs, standard TOpenDialog and TSaveDialog still use old style. For example, when Microsoft added placebar in own dialogs, VCL's dialog still use old style without placebars.

Personally I prefer to use applications that support all features of installed OS.

This is a reason why I wrote the function as wrapper for Windows API call for dialogs and now I use this function instead components. It allow not only to use all new features from Windows, but also reduce a size for exe-file and allow to use same function for both TOpenDialog and TSaveDialog functionality.

For example:
1. to display the "OpenDialog" for text files

  s := 'aaa.txt';
  if OpenSaveFileDialog(Application.Handle, 'txt', 'Text Files|*.txt', 'c:\', 'Select text file', s, True) then
    ShowMessage(s + ' file was selected for open')

2. to display the "Save dialog":

  s := 'data.dbf';
  if OpenSaveFileDialog(Application.Handle, 'dbf', 'dBase tables|*.dbf|All files|*.*', 'c:\', 'Select table', s, False) then
    ShowMessage(s + ' table was selected for save')

See full code below. Hope you'll find this code useful.

uses Windows;

function OpenSaveFileDialog(ParentHandle: THandle; const DefExt, Filter,
InitialDir, Title: string; var FileName: string; IsOpenDialog: Boolean):
Boolean;

implementation
uses ShlObj, SysUtils;

type
  POpenFilenameA = ^TOpenFilenameA;
  POpenFilename = POpenFilenameA;
  tagOFNA = packed record
    lStructSize: DWORD;
    hWndOwner: HWND;
    hInstance: HINST;
    lpstrFilter: PAnsiChar;
    lpstrCustomFilter: PAnsiChar;
    nMaxCustFilter: DWORD;
    nFilterIndex: DWORD;
    lpstrFile: PAnsiChar;
    nMaxFile: DWORD;
    lpstrFileTitle: PAnsiChar;
    nMaxFileTitle: DWORD;
    lpstrInitialDir: PAnsiChar;
    lpstrTitle: PAnsiChar;
    Flags: DWORD;
    nFileOffset: Word;
    nFileExtension: Word;
    lpstrDefExt: PAnsiChar;
    lCustData: LPARAM;
    lpfnHook: function(Wnd: HWND; Msg: UINT; wParam: WPARAM; lParam: LPARAM): UINT stdcall;
    lpTemplateName: PAnsiChar;
  end;
  TOpenFilenameA = tagOFNA;
  TOpenFilename = TOpenFilenameA;

function GetOpenFileName(var OpenFile: TOpenFilename): Bool; stdcall; external 'comdlg32.dll'  name 'GetOpenFileNameA';
function GetSaveFileName(var OpenFile: TOpenFilename): Bool; stdcall; external 'comdlg32.dll'  name 'GetSaveFileNameA';

const
  OFN_DONTADDTORECENT = $02000000;
  OFN_FILEMUSTEXIST = $00001000;
  OFN_HIDEREADONLY = $00000004;
  OFN_PATHMUSTEXIST = $00000800;

function CharReplace(const Source: string; oldChar, newChar: Char): string;
var
  i: Integer;
begin
  Result := Source;
  for i := 1 to Length(Result) do
    if Result[i] = oldChar then
      Result[i] := newChar
end;

function OpenSaveFileDialog(ParentHandle: THandle; const DefExt, Filter, InitialDir, Title: string; var FileName: string; IsOpenDialog: Boolean): Boolean;
var
  ofn: TOpenFileName;
  szFile: array[0..MAX_PATH] of Char;
begin
  Result := False;
  FillChar(ofn, SizeOf(TOpenFileName), 0);
  with ofn do
  begin
    lStructSize := SizeOf(TOpenFileName);
    hwndOwner := ParentHandle;
    lpstrFile := szFile;
    nMaxFile := SizeOf(szFile);
    if (Title <> '') then
      lpstrTitle := PChar(Title);
    if (InitialDir <> '') then
      lpstrInitialDir := PChar(InitialDir);
    StrPCopy(lpstrFile, FileName);
    lpstrFilter := PChar(CharReplace(Filter, '|', #0)+#0#0);
    if DefExt <> '' then
      lpstrDefExt := PChar(DefExt);
  end;
  if IsOpenDialog then
  begin
    if GetOpenFileName(ofn) then
    begin
      Result := True;
      FileName := StrPas(szFile);
    end;
  end
  else
  begin
    if GetSaveFileName(ofn) then
    begin
      Result := True;
      FileName := StrPas(szFile);
    end;
  end
end;

Published: October 1, 2003

See also

	Excel Web-stream
	ABA Spreadsheet Convert
	SMImport suite
	Paradox to MS Access converter
	SMDBGrid
	Word Web-stream
	Viewer for MS Outlook Messages
	SMReport
	Paradox Viewer
	Clarion Viewer

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