Question

So from what I understand of a string vs StringBuilder is that string builder will actually modify the instance of itself while string will just make a new one. So if I understand this correctly then by using the string method for a constantly changing variable I could basically be eventually using all the memory until the computer needs to dump it to make room.

What I am doing is using an event handler to monitor serial communication. I will take in the data and parse it out plus display it in a text box. The event handler uses string to accomplish this currently. In concern for better programming and not using up all the memory when I don’t need to I am trying to clean up my code.

I started to code with string builder and begun to get the build error that StringBuilder does not contain a .contains method.

Basically I am curious if i should leave it alone? Should I approach this differently? and do I have the right understanding in that string will inevitably run me out of memory?

private void DataReceivedHandler(object sender, SerialDataReceivedEventArgs e)
{
    SerialPort sp = (SerialPort)sender;

    string indata = sp.ReadExisting();
    rx.AppendText(Environment.NewLine + indata);
    string dataCheck = indata.ToUpper();
    if (dataCheck.Contains("CONNECT") || indata.Contains("CONNECTED"))
    {
        cState.Text = "Connected";
        connectLink();
    }
    if (dataCheck.Contains("NO CARRIER"))
    {
        cState.Text = "Disconnected";
        disconnect();
    }
    dataCheck = null;
}

Answer 1

You are incorrect; using String will not (in general) cause you to run out of memory.

If you’re doing lots of concatenation, using string is less efficient, since it needs to build a new string and throw away the old string every time you concatenate.
In such scenarios, you should use a StringBuilder to build the string, then call ToString() whenever you want to display it.

Your code does not contain any concatenation, so using StringBuilder wouldn’t do any good.