Code:

Uses Registry;

{©Drkb v.3(2007): www.drkb.ru,

®Vit (Vitaly Nevzorov) - nevzorov@yahoo.com}

procedure RegisterFileType(FileType,FileTypeName, Description,ExecCommand:string);

begin

if (FileType='') or (FileTypeName='') or (ExecCommand='') then exit;

if FileType[1]<>'.' then FileType:='.'+FileType;

if Description='' then Description:=FileTypeName;

with Treginifile.create do

try

rootkey := hkey_classes_root;

writestring(FileType,'',FileTypeName);

writestring(FileTypeName,'',Description);

writestring(FileTypeName+'\shell\open\command','',ExecCommand+' "%1"');

finally

free;

end;

end;

procedure TForm1.Button1Click(Sender: TObject);

begin

RegisterFileType('txt','TxtFile', 'Plain text','notepad.exe');

end;