Hello;
I'm having a problem with receiving data from serial port. There's an eventhandler(datareceived) and I'm monitoring the answer from the serial port to a text box in the eventhandler. There's no problem till here. But also I want to use the incoming data to process it in some functions. But when I assign the incoming string(from the ReadExisting() function) to a local variable there are always lots of characters missing. How do I solve this problem? The code is below:
private void port_DataReceived_1(object sender, SerialDataReceivedEventArgs e)
{
InputData = port.ReadExisting();
OutputData = InputData;
Log(InputData);
}
private void Log(string msg)
{
rtfTerminal.Invoke(new EventHandler(delegate
{
rtfTerminal.SelectedText = string.Empty;
rtfTerminal.AppendText(msg);
rtfTerminal.ScrollToCaret();
}));
}
The problem continues if I write "OutputData = InputData;" in the invoke code.
I'm waiting for your help.
8  16486 
The characters are missing because you are either not reading as fast as they are being sent and the buffer overflows OR your program is taking too long to do things and is missing the bytes.
rs232 is tricky buisness.
Try to limit what you do in that eventhandler to almost nothing. Your results should be better.
okay that may be the problem. but when I don't call the invoke method for the texbox or the other controls, there are still missing characters. So the invoke method brings the control back to the thread to what it was created from, then all the characters are shown in the textbox. Is there any method like invoke() for the variables(string,char[]) to call the threads which they were created from?
I wrote a terminal program once (and have since specialized it) but Here's what I used:
My eventhandler -
private void sp1_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)
-
{
-
dataready = true;
-
}
-
And then I had the following function and helper function: -
System.IO.Ports.SerialPort sp1;
-
private string GetData()
-
{
-
string retval = "";
-
wantingdata = true;
-
-
//attempt to wait for the dataready signal
-
DateTime Endwith = DateTime.Now.AddMilliseconds(READ_TIMEOUTMS);
-
while ((!dataready)&&(Endwith.CompareTo(DateTime.Now)>0))
-
{
-
}
-
if (!dataready)
-
{
-
return "Timed out!";
-
}
-
-
//only allow READ_TIMEOUTMS worth of miliseconds for reading
-
//i actually recomend this be redone so that each character read will reset the timeout value
-
Endwith = DateTime.Now.AddMilliseconds(READ_TIMEOUTMS);
-
//Now start reading data
-
retval = ReadSPData();
-
//I was searching for the '\r' character to determine when to stop reading
-
while ((retval.IndexOf('\r') == -1) && (Endwith.CompareTo(DateTime.Now) > 0))
-
{
-
retval += ReadSPData();
-
}
-
-
wantingdata = false;
-
if (retval.IndexOf('\r') > -1)
-
{
-
if (retval != "")//make sure I don;t have any garbage after that '\r'
-
retval = retval.Split("\r".ToCharArray(), StringSplitOptions.RemoveEmptyEntries)[0];
-
return retval.Trim();
-
}
-
else
-
{
-
return "Timed out!";//Not the most descriptive, but I didn't get a '\r' before my READ_TIMEOUTMS value was reached
-
}
-
}
-
-
private string ReadSPData()
-
{
-
string retval = "";
-
try
-
{
-
if (dataready)
-
{
-
retval += sp1.ReadExisting();
-
dataready = false;
-
}
-
}
-
catch (Exception ee)
-
{
-
EAlert(ee, "Reading SerialPort Data");
-
}
-
return retval;
-
}
-
I've never had trouble with dropping data, but I never sent massive amount at once either.
There' s still problem in reading data. I am using a datareceived event to show the retunrning values in a textbox. I need to do that and I do. But also I need to assign the answer from the serial port to use it later in some functions. For example some answers starts with "[A1]" so I don't need to assign the answer to a string; but I want to assign the answer from the serial port to a string when it returns "[A4]"+ 16 bytes of data. Also I'm using VS.NET 2005 and there's no reading method including a parameter of timeout. I'm still waiting for help.
Right, if you look at my data recieved, you'll see I only set a bit in there. Thats because if I did anything else, I was dropping characters.
Modify my read functions to run continuously in another thread or something?
Is this a command and response situation?
Like does it only send data to you after you send a command?
If so, that makes it immensly easier.
Is this a command and response situation?
Like does it only send data to you after you send a command?
If so, that makes it immensly easier.
Hello
In your code you are using
port.ReadExisting();
which indicates ,your application will read the data that present at that particular instance of time only ,there may be cases that all the data may not be reached to the port while your reads the existing data,
better try to stop your thread for a particular amount of time
so that you can read the complete data that exist in port buffer
use this slleep before your port.readexisting()
Thread.Sleep(choose some amount of time );
try it out this worksfor you
GoodLuck
my readexisting is in a loop.
It will keep reading until it is told to stop (i tell it to stop when it reads a '\r')
As I've said, I don't have any trouble with dropped characters with this solution.
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