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dirtylarry
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loop through string, if not found read more, if not found read more, if found, stop?

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i'm reading a rs232 port and i call the readexisting:

string x = port.ReadExisting();
string y;

if(x.Contains("\r"))
{
     do something;
}
else
{
     y = x + port.ReadExisting();
}

this doesn't keep looping. i want it to keep reading the port and concatenating the string until the port sends a "\r" character. how should i do this?

rs232
  • asked one year ago
  • edited one year ago
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last answered one year ago

2 answers

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tick
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thanks vulpes, i used a while loop.

string received = serialPort.ReadExisting();
            int y = received.IndexOf("\r");
            while(y ==-1)
            {
                received = received + serialPort.ReadExisting();
                y = received.IndexOf("\r");
            }

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I'd just use port.ReadLine() which will block until (by default) "\r\n" is received.

If you're only expecting "\r" then change the port's NewLine property to that.

ReadLine() doesn't return the Newline characters themselves but they are removed from the input buffer.

To avoid blocking indefinitely, you can set the port's ReadTimeout property to a reasonable value and catch the resulting TimeoutException:

port.NewLine = "\r"; // if it's not \r\n
port.ReadTimeout = 1000; // 1 second say
string y = "";

try
{
   y = port.ReadLine();
}
catch (TimeoutException) 
{ 
   MessageBox.Show("Time out occurred");
}

  • answered one year ago by:

    vulpes
    17279
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