如何在循环发送更多数据之前等待 COM 端口接收事件 [英] How to wait for COM port receive event before sending more data in a loop

问题描述

我正在使用旧的索尼爱立信手机编写和读取 AT 命令的小组件.向/从手机发送和写入完全没有问题，但是我希望能够暂停我的 SendATCmd 功能并等待 COM 端口组件通过通知事件通知我，然后再次恢复 SendATCmd 功能.

I'm working on a small component for writing and reading AT Commands using an old Sony Ericsson phone. Sending and writing to/from the phone is no problem at all, however I would like to be able to pause my SendATCmd function and wait for the COM Port component to notify me with a Notification Event, and then resume the SendATCmd function again.

场景:我想获取手机中 SMS 消息的计数.通常我只会告诉电话:嘿，你有多少条短信?手机会在通知事件中回复.都很好.

Scenario: I want to get the count of SMS messages in the phone. Normally I'd just tell the phone: Hey, how many SMS messages do you have? and the phone would reply in the notification event. Thats all good.

但我真正想做的是

if SendATCmd('CountSMS')>0 then
  for 0 to SMSCount do
    AddSMSToList;

SendATCmd 的代码如下所示:

The code for SendATCmd looks like this:

function TSE_Z1010.SendATCmd(Cmd: string): TATResult;
begin
  fCOMPort.PutString(Cmd); //Sending AT command

  //Here is where I would like to pause this function
  //wait for the fCOMPort to notify me when data is available
  //and then resume this function again.

  result:=fTMPATResult;

end;

我尝试过使用 while 循环、暂停等，但除了一件事外，没有任何效果，那就是我将 ShowMessage 放在应该暂停的地方.我不知道 ShowMessage 在内部是如何工作的，但它似乎不会像 while-loop 和 pause 那样停止程序.

I've tried using a while-loop, pause, etc etc, but nothing's worked except for one thing, and that's when I put a ShowMessage where the pause should be. I don't know how ShowMessage works internally but it seems that it doesn't halt the program like while-loop and pause do.

=====================

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修复它.

我所要做的就是在uses子句中添加Forms，然后添加while fTMPATResult.Full=false do Application.ProcessMessages;在我想暂停程序的部分.

All I had to do was to add Forms in the uses clause, and then I added while fTMPATResult.Full=false do Application.ProcessMessages; in the part where I wanted to pause the procedure.

fTMPATResult"是组件内全局存储传入 COM 端口数据的变量.

"fTMPATResult" is the variable where the incoming COM Port data is stored, globally within the component.

推荐答案

虽然 AsyncPro 确实有一些解决方案(ontriggerdata)，但它们是基于事件的，使代码难以阅读/理解.

While AsyncPro does have some solutions for this (ontriggerdata), they are event based and make code difficult to read/understand.

这里是带有 AsyncPro 的 SendAndWaitForResponse(就像 Remy 建议的那样):

here is SendAndWaitForResponse with AsyncPro (like Remy suggested):

TForm1 = class(TForm)
 ...
private
    IOEvent           : THandle; // used for IO events
    IORx              : string;
    Comport           : TapdComport;
...


procedure TForm1.ComportTriggerAvail(CP: TObject; Count: Word);

var i       : integer;

begin
 for i:=1 to Count do
  IORx:=IORx+Comport.GetChar;
 SetEvent(IOEvent);
end;

function TForm1.SerialSAWR(tx : string; TimeOut : integer) : boolean;
begin
 Result := False;
 try
  IORx := ''; // your global var
  ResetEvent(IOEvent);
  Comport.PutString(tx);
  Result := WaitForSingleObject(IOEvent, TimeOut) = WAIT_OBJECT_0;
 except
  on E : Exception do
   // dosomething with exception
 end;
end;

// constructor part
IOEvent := CreateEvent(nil, True, False, nil);
// destructor part
 if IOEvent <> 0 then
  CloseHandle(IOEvent);

最好的解决方案是使用 comport 创建一个线程，这样您的 GUI 就不会被阻塞.我有几个使用 Asyncpro 生产的应用程序，它就像一个魅力......

Best solution is to create a thread with the comport so your GUI won't be blocked. I have several applications in production with Asyncpro this way and it works like a charm...

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