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[求助]从SERIAL PORT读取数据.

rainzw(rainzw)

我参照例子, 用CREATEFILE取的COM1的HANDLE, 然后设置其配置, 最后, 用READFILE来获取COM1的数据, 但是, 每次一到READFILE, 就会报 INVALID HANDLE的错误.

大致代码:
//取得COM1的HANDLE
HANDLE m_Port = CreateFile("COM1:",GENERIC_READ|GENERIC_WRITE,0,NULL,OPEN_EXISTING,0,NULL);
if (m_Port == INVALID_HANDLE_VALUE){
// Handle the error.
return false ;
}

// 配置COM1
DCB dcb;

if (!GetCommState(m_Port, &dcb)){
return false;
}

dcb.BaudRate = CBR_9600; // set the baud rate
dcb.ByteSize = 8; // data size, xmit, and rcv
dcb.Parity = NOPARITY; // no parity bit
dcb.StopBits = ONESTOPBIT; // one stop bit

if (!SetCommState(m_Port, &dcb)){
return false;
}

//读取数据
char input[200];
unsigned int lenBuff = 200;
LPDWORD lenMessage;

String *strResult;

if(ReadFile(m_Port,input,lenBuff,lenMessage,NULL)==0){ //这里会有EXCEPTION
return false;
}

(#1668099@0)
Last Updated: 2004-4-1
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工作学习 / IT技术讨论 / [求助]从SERIAL PORT读取数据. -rainzw(rainzw); 2004-4-1 {921} (#1668099@0)
我参照例子, 用CREATEFILE取的COM1的HANDLE, 然后设置其配置, 最后, 用READFILE来获取COM1的数据, 但是, 每次一到READFILE, 就会报 INVALID HANDLE的错误.

大致代码:
//取得COM1的HANDLE
HANDLE m_Port = CreateFile("COM1:",GENERIC_READ|GENERIC_WRITE,0,NULL,OPEN_EXISTING,0,NULL);
if (m_Port == INVALID_HANDLE_VALUE){
// Handle the error.
return false ;
}

// 配置COM1
DCB dcb;

if (!GetCommState(m_Port, &dcb)){
return false;
}

dcb.BaudRate = CBR_9600; // set the baud rate
dcb.ByteSize = 8; // data size, xmit, and rcv
dcb.Parity = NOPARITY; // no parity bit
dcb.StopBits = ONESTOPBIT; // one stop bit

if (!SetCommState(m_Port, &dcb)){
return false;
}

//读取数据
char input[200];
unsigned int lenBuff = 200;
LPDWORD lenMessage;

String *strResult;

if(ReadFile(m_Port,input,lenBuff,lenMessage,NULL)==0){ //这里会有EXCEPTION
return false;
}

It seems ok. Why not post all code? -bugkiller(Driver Coding); 2004-4-2 (#1669119@0)

全部代码就是这样了. 我试过CBUILDER, 试过.NET, 都一样, 说那个HANDLE无效. -rainzw(rainzw); 2004-4-2 (#1669186@0)

try "COM1" or "\\\\.\\COM1" -canadiantire(Crappy Tire); 2004-4-2 (#1669361@0)

same. 我的机器有COM1 AND COM2, 我用COM1:, COM1, COME2, COM2, \\\\.\\COM1, 都可以在CREATEFILE取得HANDLE, -rainzw(rainzw); 2004-4-2 {186} (#1669619@0)
而一旦我用COM3, 就会在开始FAIL, INVALID HANDLE, 我就是不明白, 怎么开始都行, 到了READFILE就出错了, CBUILDER说是ACCESS VIOLATION, .NET说是什么OBJECT REFERENCE 没有定义, 总之就是HANDLE无效.

try seek to the begin of the file -argcsina(我是陌生人); 2004-4-2 (#1669641@0)

什么意思? 能详细点么?本人编程初级水平... -rainzw(rainzw); 2004-4-2 (#1669713@0)

I mean ,using fseek function move file pointer to the begin of the file -argcsina(我是陌生人); 2004-4-3 (#1670353@0)

记得以前Windows缺省并没有COM3,你需要到Control Panel加一个虚的。 -canadiantire(Crappy Tire); 2004-4-2 (#1669750@0)

我不知道怎么加一个虚拟的, 但是我可以这样一来, DISABLE COM2, 再运行程序, COM2在CREATEFILE就是INVALID HANDLE了. -rainzw(rainzw); 2004-4-2 {72} (#1669781@0)
就是说, 从CREATEFILE, 到SETCOMM, HANDLE都是可以的, 一到READFILE就歇菜了.

There is no COM3 at all. -bugkiller(Driver Coding); 2004-4-5 (#1672818@0)

debug the code to find out when the handle becomes invalid.... -dundas888(登达寺); 2004-4-2 (#1669699@0)

就在READFILE那一行里面, 我COMMENTS了所有关于CONFIGURATION的代码. -rainzw(rainzw); 2004-4-2 {502} (#1669709@0)
HWND m_Port;
try{
//open handle
m_Port = CreateFile("COM1",GENERIC_READ|GENERIC_WRITE,0,NULL,OPEN_EXISTING,0,NULL);

if (m_Port == INVALID_HANDLE_VALUE){
// Handle the error.
Memo->Lines->Add("Invalid Handle");
return;
}

char input[200];
unsigned int lenBuff = 200;
LPDWORD lenMessage;

if(ReadFile(m_Port,input,lenBuff,lenMessage,NULL)==0){
Memo->Lines->Add("Failed in Reading Data");
}else{
Memo->Lines->Add(input);
}

Change lenMessage from LPDWORD to DWORD, use &lenMessage in ReadFile (). It will be ok. -bugkiller(Driver Coding); 2004-4-5 (#1672837@0)

@Calgary

[求助]从SERIAL PORT读取数据.

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