How to solve serial port data conversion error?

Question

C++ / C#

I receive data from the COM port. The value comes from 0 to 100.
When I try to convert to int, an error pops up (screen is attached).
The code itself:

string inpSerial = serialPort1.ReadExisting();
label1.Text = inpSerial;
int numm = int.Parse(inpSerial);
progressBar1.Value = numm;

Error:

If you try to get through serialPort1.ReadLine();, and not through serialPort1.ReadExisting();, then the error does not appear, but this option does not suit me because performance drops.

Answer 1

What happens inpSerialwhen an error occurs? Obviously not a number.

bool successfullyParsed = int.TryParse(inpSerial, out num);
if (successfullyParsed){
    // ...
}

where num is a parsed number, in case of an error successfullyParsed will contain false
https://docs.microsoft.com/en-us/dotnet/api/system...