使用printers组件设计打印程序，请问怎么判断打印机是否联机？

Question

如题

Answer 1

try
  printer.BeginDoc;
except
  
end;

Answer 2

try
  printer.BeginDoc;
except
  
end;
我试过了，用这种方法无法测试打印机是否联机

Answer 3

var
 mPrintHandle:THandle;
lRet:LongBool;                     
Job_Info:array[0..99] of _JOB_INFO_2;
...
  
begin
  lRet:=OpenPrinter(PChar(PrinterName), mPrintHandle, nil);
  if lRet=false then
  begin
    timer1.Enabled:=false;
    showmessage('打印机名错');
    exit;
  end;
  If mPrintHandle <> 0 Then
  begin
    s:=Sizeof(Job_Info);
    cbNeeded:=0;
    cReturned:=0;
    lRet:=EnumJobs(mPrintHandle,0,99,2,@Job_Info,s,cbNeeded,cReturned);
  end;
  if lRet=false then
  begin
    showmessage('错误'+inttostr(GetlastError));
    exit;
  end;
  i:=0;
  if (Job_Info[0].Status=JOB_STATUS_PRINTING)and(Job_Info[0].jobId<>Idno) then
  begin
.....状态得到

Answer 4

to:liangyong007a(（梦里有云，心中有天地）（探花秀）)
老大你能注释一下吗?没用过,比较糊涂哦.饿也在关注此话题.呵呵,谢谢了