C++Builder中动态更改自定义打印纸张

void __fastcall TForm1::BitBtn1Click(TObject *Sender)
{
char *ADevice, *ADriver, *APort;
THandle DeviceMode;
PDeviceMode DevMode;
int length,width;
length=1400;
width=2410;//设定自定义纸张的尺寸单位为0.1毫米
ADevice =new char[100];
ADriver =new char[100];
APort =new char[100];
//获取打印机
Printer()->GetPrinter(ADevice, ADriver, APort,DeviceMode);
//获取PDevMode结构
DevMode =(_devicemodeA*) GlobalLock((void *)DeviceMode);
//设定可以修改的值
DevMode->dmFields = DevMode->dmFields|DM_PAPERSIZE;
DevMode->dmFields = DevMode->dmFields|DM_PAPERLENGTH;
DevMode->dmFields = DevMode->dmFields|DM_PAPERWIDTH;
//设定要修改的值
DevMode->dmPaperSize=DMPAPER_USER;//设为自定义纸张
DevMode->dmPaperLength=length;
DevMode->dmPaperWidth=width;

//测试打印
Printer()->BeginDoc();
TextOut(Printer()->Handle, 0, 0, "-----------------",17);
Printer()->NewPage();
TextOut(Printer()->Handle, 0, 0, "++++++++++++++++++",18);
Printer()->NewPage();
Printer()->EndDoc();
}