GetSaveFileName fails with CDERR_FINDRESFAILURE - c++

Question

I've written a TOpenPictDialog (source code see below) component, which finally fails under certain circumstands when calling
Result := TDialogFunc(DialogFunc)(DialogData);
in Dialogs.pas. As DialogFunc correctly points to GetOpenFileName I call CommDlgExtendedError afterwards for test to find out what's wrong. It returns CDERR_FINDRESFAILURE. In this case the dialog is simply not showing. My test form only contains a button and the TOpenPictDialog component, when pressing the button, OpenPictDialog1->Execute is called - that's all.
The very strange thing is that it does work perfectly (besides of the TListView flickering on resize) under one of the following circumstands:
a) add ExtDlgs in "uses" in calling form
b) add an original TOpenPictureDialog to the form without calling it
c) adding the PAS file containing TOpenPictDialog to the project (although TOpenPictDialog has been already installed)
If I write a C++ Builder application with the one calling form I never get TOpenPictDialog working (even if I add the additional TOpenPictureDialog component).
unit PictureDlg;
{$R-,H+,X+}
{$IF CompilerVersion > 23} {$DEFINE GE_DXE2} {$IFEND}
interface
{$IFDEF GE_DXE2}
uses Winapi.Messages, Winapi.Windows, System.SysUtils, System.Classes, Vcl.Controls, Vcl.StdCtrls,
Vcl.Graphics, Vcl.ExtCtrls, Vcl.Buttons, Vcl.Dialogs, Vcl.ExtDlgs, Vcl.Consts, Vcl.ComCtrls;
{$ELSE}
uses Messages, Windows, SysUtils, Classes, Controls, StdCtrls,
Graphics, ExtCtrls, Buttons, Dialogs, ExtDlgs, Consts, ComCtrls;
{$ENDIF}
(*$HPPEMIT '// Alias records for C++ code that cannot compile in STRICT mode yet.' *)
(*$HPPEMIT '#if defined(_VCL_ALIAS_RECORDS)' *)
(*$HPPEMIT '#if !defined(STRICT)' *)
// (*$HPPEMIT ' #pragma alias "#Vcl#Extdlgs#TOpenPictDialog#Execute$qqrpv"="#Vcl#Extdlgs#TOpenPictDialog#Execute$qqrp6HWND__"' *)
(*$HPPEMIT '#endif' *)
(*$HPPEMIT '#endif' *)
type
{ TOpenPictDialog }
TOpenPictDialog = class(TOpenDialog)
private
FListView: TListView;
FTopLabel, FBottomLabel: TStaticText;
FImageCtrl: TImage;
FSavedFilename: string;
FOldDialogWndProc: Pointer;
FDialogMethodInstance: Pointer;
FDialogHandle: THandle;
function IsFilterStored: Boolean;
procedure DialogWndProc(var Msg: TMessage);
protected
procedure DoClose; override;
procedure DoSelectionChange; override;
procedure DoShow; override;
function TaskModalDialog(DialogFunc: Pointer; var DialogData): Bool; override;
published
property Filter stored IsFilterStored;
public
constructor Create(AOwner: TComponent); override;
function Execute(ParentWnd: HWND): Boolean; override;
property DialogListView: TListView read FListView;
property DialogImage: TImage read FImageCtrl;
property TopLabel: TStaticText read FTopLabel;
property BottomLabel: TStaticText read FBottomLabel;
end;
procedure Register;
implementation
uses
{$IFDEF GE_DXE2}
{$IF DEFINED(CLR)}
System.Runtime.InteropServices, System.Reflection, System.Security.Permissions, System.IO,
{$IFEND}
System.Math, Vcl.Forms, Winapi.CommDlg, Winapi.Dlgs, System.Types, Winapi.ShlObj, Winapi.ActiveX;
{$ELSE}
{$IF DEFINED(CLR)}
InteropServices, Reflection, Permissions, IO,
{$IFEND}
Math, Forms, CommDlg, Dlgs, Types, ShlObj, ActiveX;
{$ENDIF}
{ TOpenPictDialog }
constructor TOpenPictDialog.Create(AOwner: TComponent);
begin
FDialogHandle := 0;
FDialogMethodInstance := NIL;
inherited Create(AOwner);
Filter := GraphicFilter(TGraphic);
FListView := TListView.Create(Self);
FImageCtrl := TImage.Create(Self);
with FListView do
begin
Name := 'ListView';
SetBounds(204, 5, 169, 200);
BevelOuter := bvNone;
BorderWidth := 6;
TabOrder := 1;
Color := clWindow;
ParentDoubleBuffered := false;
DoubleBuffered := true;
OwnerDraw := true;
Ctl3D := true;
with FImageCtrl do
begin
Picture := nil;
Name := 'Image';
Parent := FListView;
end;
end;
FTopLabel := TStaticText.Create(Self);
with FTopLabel do
begin
Name := 'TopLabel';
SetBounds(6, 6, 157, 23);
AutoSize := False;
Caption := 'Preview:';
end;
FBottomLabel := TStaticText.Create(Self);
with FBottomLabel do
begin
Name := 'BottomLabel';
SetBounds(6, 6, 157, 23);
AutoSize := False;
Caption := 'Image size: 208 x 149 px';
Alignment := taCenter;
end;
end;
procedure TOpenPictDialog.DialogWndProc(var Msg: TMessage);
var
PreviewRect, ListViewRect, WindowRect, LabelRect: TRect;
WndControl: HWND;
begin
Msg.Result := CallWindowProc(FOldDialogWndProc, FDialogHandle, Msg.Msg, Msg.WParam, Msg.LParam);
if ((Msg.Msg = WM_WINDOWPOSCHANGED) and
((TWMWindowPosMsg(Msg).WindowPos.Flags and SWP_NOSIZE) = 0)) or
(Msg.Msg = WM_SHOWWINDOW) then begin
PreviewRect := FListView.BoundsRect;
GetWindowRect(Handle, WindowRect);
WndControl := FindWindowEx(FDialogHandle, 0, 'SHELLDLL_DefView', nil);
WndControl := FindWindowEx(WndControl, 0, 'SysListView32', nil);
if WndControl <> 0 then begin
GetWindowRect(WndControl, ListViewRect);
PreviewRect.Top := ListViewRect.Top - WindowRect.Top;
PreviewRect.Bottom := PreviewRect.Top + ListViewRect.Bottom - ListViewRect.Top;
if (not EqualRect(PreviewRect, FListView.BoundsRect)) then
FListView.BoundsRect := PreviewRect;
LabelRect := PreviewRect;
Dec(LabelRect.Top, 24);
LabelRect.Bottom := LabelRect.Top + 16;
FTopLabel.BoundsRect := LabelRect;
LabelRect := PreviewRect;
LabelRect.Top := PreviewRect.Bottom + 9;
LabelRect.Bottom := LabelRect.Top + 16;
FBottomLabel.BoundsRect := LabelRect;
end;
end;
end;
procedure TOpenPictDialog.DoSelectionChange;
var
FullName: string;
function ValidFile(const FileName: string): Boolean;
begin
Result := FileGetAttr(FileName) <> -1;
end;
begin
FullName := FileName;
if FullName <> FSavedFilename then
begin
FSavedFilename := FullName;
end;
inherited DoSelectionChange;
end;
procedure TOpenPictDialog.DoClose;
begin
if Assigned(FDialogMethodInstance) then begin
SetWindowLong(FDialogHandle, GWL_WNDPROC, Integer(FOldDialogWndProc));
FreeObjectInstance(FDialogMethodInstance);
end;
FDialogHandle := 0;
FDialogMethodInstance := NIL;
inherited DoClose;
{ Hide any hint windows left behind }
Application.HideHint;
end;
procedure TOpenPictDialog.DoShow;
var
PreviewRect, StaticRect, OldDialogRect: TRect;
DialogWidth, DialogHeight, NewLeft, NewTop: integer;
const
SizeIncrease = 25;
begin
FDialogHandle := GetParent(Handle);
GetWindowRect(FDialogHandle, OldDialogRect);
DialogWidth := OldDialogRect.Right - OldDialogRect.Left + SizeIncrease;
DialogHeight := OldDialogRect.Bottom - OldDialogRect.Top;
NewLeft := (Screen.Width - DialogWidth) div 2;
NewTop := (Screen.Height - DialogHeight) div 2;
GetWindowRect(Handle, PreviewRect);
MoveWindow(FDialogHandle, NewLeft, NewTop, DialogWidth, DialogHeight, true);
MoveWindow(Handle, 0, 0, PreviewRect.Right - PreviewRect.Left + SizeIncrease, PreviewRect.Bottom - PreviewRect.Top, false);
StaticRect := GetStaticRect;
GetClientRect(Handle, PreviewRect);
PreviewRect.Left := StaticRect.Left + (StaticRect.Right - StaticRect.Left);
Inc(PreviewRect.Top, 4);
Dec(PreviewRect.Right, 8);
Dec(PreviewRect.Bottom, 20);
FListView.BoundsRect := PreviewRect;
FDialogMethodInstance := MakeObjectInstance(DialogWndProc);
FOldDialogWndProc := Pointer(SetWindowLong(FDialogHandle, GWL_WNDPROC, Integer(FDialogMethodInstance)));
FSavedFilename := '';
FListView.ParentWindow := Handle;
FTopLabel.ParentWindow := Handle;
FBottomLabel.ParentWindow := Handle;
inherited DoShow;
end;
[UIPermission(SecurityAction.LinkDemand, Window=UIPermissionWindow.SafeSubWindows)]
function TOpenPictDialog.Execute(ParentWnd: HWND): Boolean;
begin
if NewStyleControls and not (ofOldStyleDialog in Options) and not
((Win32MajorVersion >= 6) and UseLatestCommonDialogs) then
Template := 'DLGTEMPLATE'
else
{$IF DEFINED(CLR)}
Template := '';
{$ELSE}
Template := nil;
{$IFEND}
Result := inherited Execute(ParentWnd);
end;
function TOpenPictDialog.TaskModalDialog(DialogFunc: Pointer; var DialogData): Bool;
begin
// This makes sense ONLY if you are compiling with a run-time packages
// Thanks to Peter Below (www.delphifaq.com)
TOpenfilename(Dialogdata).hInstance := FindClassHInstance(Classtype);
Result := inherited TaskModalDialog(DialogFunc, DialogData);
end;
function TOpenPictDialog.IsFilterStored: Boolean;
begin
Result := not (Filter = GraphicFilter(TGraphic));
end;
procedure Register;
begin
RegisterComponents('Dialogs', [TOpenPictDialog]);
end;
end.

Answer 1

When you copied the code from ExtDlgs.pas to begin writing yours, you didn't copy enough. In particular, you didn't copy the $R directive that links the associated ExtDlgs.rc file, which contains the dialog resource describing the additional layout of the custom dialog box.
Your code tells the API to use a dialog resource named DLGTEMPLATE, but you haven't included that resource in your program. That explains why the error code you get is about a failure to find a resource. Using the ExtDlgs unit has the side effect of linking that unit's associated resources.
Go copy the dialog template from ExtDlgs.rc into your own RC file and link it as ExtDlgs.pas does. Use a different name for the resource, though, to avoid a name clash with the existing DLGTEMPLATE resource. Adjust your code accordingly.