Title: Getting the associated Icon of any file
Question: This article shows you how to extract the associated icon of any file. Including files that use shell icon handlers such as ICO and Corel Draw files.
Answer:
Just a few days ago, I published an article on creating an shell icon handler allowing you to manually create icons for every file of a specific file type.
This article shows you how to get such icons without much work. Using the function SHGetFileInfo from the ShellAPI unit it is a rather simple task.
This article will simply provide you with the steps you have to take in order to get the icon.
Starting with creating a new application drop a PaintBox, a Button and a OpenDialog on the form. Fill the Button OnClick with the following procedure:
procedure TForm1.Button1Click(Sender: TObject);
begin
if OpenDialog1.Execute then
DrawFile(OpenDialog1.FileName);
end;
Next you need the DrawFile method. The lines are commented.
procedure TForm1.DrawFile(Name: String);
var
FileInfo: TSHFileInfo;
ImageListHandle: THandle;
aIcon: TIcon;
begin
// clear the memory
FillChar(FileInfo, SizeOf(FileInfo), #0);
// get a handle to the ImageList for the file selected
ImageListHandle := SHGetFileInfo(
PChar(Name), 0, FileInfo, SizeOf(FileInfo),
// we want an icon in LARGE
SHGFI_ICON or SHGFI_LARGEICON
);
try
// create a icon class
aIcon := TIcon.Create;
try
// assign the handle of the icon returned
aIcon.Handle := FileInfo.hIcon;
// lets paint it transparent
aIcon.Transparent := True;
with PaintBox1 do begin
// resize the paint box to icon size
Width := aIcon.Width;
Height := aIcon.Height;
// tell our app to first resize the paint box before we draw the icon
Application.ProcessMessages;
// clear the paintbox
Canvas.Rectangle(-1, -1, Succ(Width), Succ(Height));
// copy the icon
Canvas.Draw(0, 0, aIcon);
end;
finally
// free our icon class
FreeAndNil(aIcon);
end;
finally
// !!! FREE THE ICON PROVIDED BY THE SHELL
DestroyIcon(FileInfo.hIcon);
// free the image list handle
ImageList_Destroy(ImageListHandle);
end;
end;
I hope this will help you.
Daniel Wischnewski.