Author: Jonas Bilinkevicius

Does anyone know how to set a particular printer as the default printer 
programmatically in Windows (both 98 and NT) in Delphi?

Answer:

Change default printer:

1   { ... }
2   var
3     Device: array[0..255] of char;
4     Driver: array[0..255] of char;
5     Port: array[0..255] of char;
6     hDeviceMode: THandle;
7   begin
8     Printer.PrinterIndex := ....; {select printer to make default}
9     Printer.GetPrinter(Device, Driver, Port, hDeviceMode);
10    StrCat(Device, ',');
11    StrCat(Device, Driver);
12    StrCat(Device, ',');
13    StrCat(Device, Port);
14    WriteProfileString('windows', 'device', Device);
15    StrCopy(Device, 'windows');
16    SendMessage(HWND_BROADCAST, WM_WININICHANGE, 0, longint(@Device));
17  end;