C# How to read and cache text file data?

below is a more complicated way of doing it and yes, you could do this a bunch of different ways, you could use string.Split and split on the ending square bracket, returning kind of a key value pair. the example below will get you there.

 using System.Collections.Generic;
 using System.IO;
 
 //...normal stuff
 
 List<string> fileLines = new List<string>(File.ReadLines("somepathtothefile"));
 string serverName = string.Empty;
 
 foreach(string line in fileLines) {
   if (line.Contains("[serverName]")) {
     var lastEndingBracket = line.LastIndexOf("]");
     serverName = line.SubString(lastEndingBracket + 1, line.Length);
   }
 }
 
 // ... other crap

Explaination: We create a List of string, read each line from the file and add it as an item/entry in the List.

We create an empty serverName string for the server name, you can similar for the ip. using null or string.empty allows you to do conditions using string.IsNullOrEmpty for example.

We then iterate over each line in the List of string(or the list of lines from the file), we check to see if the line contains(could use StartsWith) the value [serverName], if it doesn't, we move on. If it does we get the index(zero based from the left first character in that string(0) to the last closing square bracket(1)) of the last square bracket on the line(in the string) and pump it into a int var(we can infer the type value due to LastIndexOf returning an int type).

We then set serverName to the serverName, we are using SubString to begin the hacking of the string plus one(to move to the next character) all the way to the end of the string(the length). At this point you could break from the foreach look or continue if you also were looking for the ip address.