Question

I have a text file in which I need to add some lines after a particular line is encountered.

I have tried making an stream object and then reading from the file until I get the search text and then writing to the same stream by setting its cursor position, but it does not work.

Is there any way to do this?

Answer 1

here’s how you can append some text in the middle of the file:

var sb = new StringBuilder();
using (var sr = new StreamReader("inputFileName"))
{
    string line;
    do
    {
        line = sr.ReadLine();
        sb.AppendLine(line);
    } while (!line.Contains("<Sim Properties>"));

    sb.Append(myText);
    sb.Append(sr.ReadToEnd());
}

using (var sr = new StreamWriter("outputFileName"))
{
    sr.Write(sb.ToString());
}

this will insert myText after the line that contains <Sim Properties>.