Find the line number of a string

[makdu]

hi,
i want to know the line number of a particular string in a text file.

       string filePath = @"d:\file.txt";
            StreamReader streamReader = new StreamReader(filePath);
            string text = streamReader.ReadToEnd();
           
            streamReader.Close();

            string regMatch = "Active Routes:";//string to search for inside of text file. It is case sensitive.
            if (Regex.IsMatch(text, regMatch))//If the match is found in allRead
            {
                Console.WriteLine("found\n");
                            

            }

I want to have line number of the matching string

[sciguyryan]

My advice would be to read the file into a string array then cycle it with a for loop. Then you'll automatically be able to find the line number that the item is on.

[jmcilhinney]

First up, if you want to read all of a file then I'd suggest not using a StreamReader as there are easier ways. If you want to read the entire file as a single string then you should call File.ReadAllText and if you want to read the individual lines then you should call File.ReadAllLines.

In your case you are looking for a line so you obviously want to read lines, but there's really no point reading the whole file if you don't have to. If you find a match on the first line then there's no point reading any further. As such, you should use a StreamReader and read the file line by line. You would start a counter at zero and increment it each time you call ReadLine. You then test the line you just read and, if it's a match, you use the current counter value and close the file.