关于opendialog的一个问题(100分)

在opendialog->option->ofExtensionDifferent
不知用途是如何?

无论我输入的扩展名是否和defaultext一样都好象没什么反应的

有没有什么办法实验出它的效果或用途究竟是怎样的

This flag is turned on at runtime whenever the selected filename has an
extension that differs from DefaultExt. <U>If you use this flag in an
application, remember to reset it.</U>
根据帮助文档中的说明，这个参数是在运行时被程序自动设置的，不要人为设置。

我选的文件*.ico 而defaultExt是*.txt,但在下面的程序中没有显示showmessage
opendialog1.execute;
if (ofExtensionDifferent in OpenPictureDialog1.Options) then
begin
showmessage('in')
end;

procedure TForm1.Button1Click(Sender: TObject);

begin
OpenPictureDialog1.FileName := GraphicFileMask(TIcon);

OpenPictureDialog1.DefaultExt := GraphicExtension(TIcon);
OpenPictureDialog1.Options := [ofFileMustExist, ofHideReadOnly, ofNoChangeDir ];

begin
if OpenPictureDialog1.Execute then
begin
if not (ofExtensionDifferent in OpenPictureDialog1.Options) then

showmessage('bad')
else
showmessage('good');
end;

end;
end;

接受答案了.

接受答案了.