Fastest way to get shell icon

问题:

I'm using this code for getting the shell icon (the one displayed in Windows Explorer).
Does anyone has an experience with a faster way to get these icons ? The SHGetFileInfo seems to be quite slow.

procedure TForm2.Button1Click(Sender: TObject);
var
  FileInfo: TSHFileInfo;
begin
  FillChar(FileInfo, SizeOf(FileInfo), 0);
  if SHGetFileInfo(PChar('c:\windows\'), 0, FileInfo, SizeOf(FileInfo),
    SHGFI_ICON or SHGFI_SMALLICON or SHGFI_SYSICONINDEX) <> 0 then 
    DrawIconEx(Canvas.Handle, 10, 10, FileInfo.hIcon, 0, 16, 16, 0, DI_IMAGE or 
      DI_MASK);
end;

Thanks!

回答1:

Try using the SHGFI_USEFILEATTRIBUTES flag as well. See the articles Tuning SHGetFileInfo for Optimum Performance and What does SHGFI_USEFILEATTRIBUTES mean? for more information.

回答2:

I have used a cache when I used SHGetFileInfo. Unless it is an .exe or .ico file (and perhaps a few more) the icon will be the same for the same file extension, so when you show a dir list you can use the same icon for files of the same type and you don't have to call (and wait for) SHGetFileInfo again.