如何在 C# 中切断来自串口的字符串？

Question

I receive data from a serial comport and I use ReadLine to get this data. Here is the data:

#MASTERPOSA,COM1,0,21.5,FINESTEERING,1544,340322.000,02000008,5009,4655;
SOL_COMPUTED,NARROW_INT,51.11604599076,-114.03855412002,1055.7756,16.9000,
WGS84,0.0090,0.0086,0.0143,"AAAA",0.0,0.0,13,13,13,12,0,0,0,0*a72e8d3f

I want to get the data until AAAA , which is

#MASTERPOSA,COM1,0,21.5,FINESTEERING,1544,340322.000,02000008,5009,4655;
SOL_COMPUTED,NARROW_INT,51.11604599076,-114.03855412002,1055.7756,16.9000,
WGS84,0.0090,0.0086,0.0143

I used the TrimEnd method but it does not work:

textBox2.Text = data.TrimEnd(' ', '"').ToString();

Answer 1

"Cut" the string with Substring() method from the first index to the index of ",AAAA"

private static void Example()
{
  string target = "#MASTERPOSA,COM1,0,21.5,FINESTEERING,1544,340322.000,02000008,5009,4655; SOL_COMPUTED,NARROW_INT,51.11604599076,-114.03855412002,1055.7756,16.9000, WGS84,0.0090,0.0086,0.0143,\"AAAA\",0.0,0.0,13,13,13,12,0,0,0,0*a72e8d3f";
  string newstring = target.Substring(0, target.IndexOf(",\"AAAA\""));
  Console.WriteLine(newstring);
}

Answer 2

You may find the "AAAA" index first (with escaped double quotes), then use Substring method

var index = str.IndexOf("\"AAAA\"", StringComparison.Ordinal);
var result = str.Substring(0, index - 1);

It gives you the following result

#MASTERPOSA,COM1,0,21.5,FINESTEERING,1544,340322.000,02000008,5009,4655; SOL_COMPUTED,NARROW_INT,51.11604599076,-114.03855412002,1055.7756,16.9000, WGS84,0.0090,0.0086,0.0143

Answer 3

string text = "#MASTERPOSA,COM1,0,21.5,FINESTEERING,1544,340322.000,02000008,5009,4655; SOL_COMPUTED,NARROW_INT,51.11604599076,-114.03855412002,1055.7756,16.9000, WGS84,0.0090,0.0086,0.0143,\"AAAA\",0.0,0.0,13,13,13,12,0,0,0,0*a72e8d3f";
    
Regex regex = new Regex($"(^.*?)(\"AAAA\")", RegexOptions.IgnoreCase);//or other options

string newstring =  regex.Match(text).Groups[1].Value;

You can use any regex. In this example:

• Groups[0]: required text with "AAAA"
• Groups[1]: required text without "AAAA"
• Groups[2]: "AAAA"