//一个主form，有一个TComboBox控件和label控件，你看看就知道了。
unit MainFrm;
interface
uses
Windows, Messages, SysUtils, Classes, Graphics, Controls, Forms, Dialogs,
StdCtrls;
type
TMainForm = class(TForm)
cbPrinters: TComboBox;
lblPrinter: TLabel;
procedure FormCreate(Sender: TObject);
procedure cbPrintersChange(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;
var
MainForm: TMainForm;
implementation
uses IniFiles, Printers;
{$R *.DFM}
procedure TMainForm.FormCreate(Sender: TObject);
begin
{ Copy the printer names to the combobox and set the combobox to
show the currently selected default printer }
cbPrinters.Items.Assign(Printer.Printers);
cbPrinters.Text := Printer.Printers[Printer.PrinterIndex];
// Update the label to reflect the default printer
lblPrinter.Caption := Printer.Printers[Printer.PrinterIndex];
end;
procedure TMainForm.cbPrintersChange(Sender: TObject);
var
IniFile: TIniFile;
TempStr1, TempStr2: String;
S: array[0..64] of char;
begin
with Printer do
begin
// Set the new printer based on the ComboBox's selected printer
PrinterIndex := cbPrinters.ItemIndex;
// Store the printer name into a temporary string
TempStr1 := Printers[PrinterIndex];
// Delete the unnecessary portion of the printer name
System.Delete(TempStr1, Pos(' on ', TempStr1), Length(TempStr1));
// Create a TIniFile class
IniFile := TIniFile.Create('WIN.INI');
try
// Retrieve the device name of the selected printer
TempStr2 := IniFile.ReadString('Devices', TempStr1, '');
// Change the default printer to that chosen by the user
IniFile.WriteString('windows', 'device', TempStr1 + ',' + TempStr2);
// Tell all windows that the default printer changed.
StrCopy(S, 'windows');
SendMessage(HWND_BROADCAST, WM_WININICHANGE, 0, LongInt(@S));
finally
IniFile.Free;
end;
end;
// Update the label to reflect the new printer selection
lblPrinter.Caption := Printer.Printers[Printer.PrinterIndex];
end;
end.
