Delphi

Question:
It will be nice if I can associate an application to a file extension. I know, windows already has it, but I wish to have more simple and faster application. How?

Answer:
This can only be done with work around in registry,
thanks God, and thanks to borland that delphi has uses to complete this work done.
Here the example.

uses
registry, shlobj;

procedure TForm1.RegisterFileType(prefix: string; exepfad: string);
var
reg: TRegistry;
begin
reg := TRegistry.Create;
try
reg.RootKey := HKEY_CLASSES_ROOT;
reg.OpenKey('.' + prefix, True);
try
reg.Writestring('', prefix + 'file');
finally
reg.CloseKey;
end;
reg.CreateKey(prefix + 'file');
reg.OpenKey(prefix + 'file\DefaultIcon', True);
try
reg.Writestring('', exepfad + ',0');
finally
reg.CloseKey;
end;
reg.OpenKey(prefix + 'file\shell\open\command', True);
try
reg.Writestring('', exepfad + ' "%1"');
finally
reg.CloseKey;
end;
finally
reg.Free;
end;
SHChangeNotify(SHCNE_ASSOCCHANGED, SHCNF_IDLIST, nil, nil);
end;

procedure TForm1.Button1Click(Sender: TObject);
begin
RegisterFileType('pci', 'c:\file.exe');
end;