Getting specified text from text file

[AceInfinity]

I can see dublicates also , same name twice when user was disconnected and connected back for example. it doesnt check for dublicates and list only online users.

Because you're appending to the text, you need to clear it out before updating it. Also, it changes to [Connected] if it finds one of these 3

1. is connecting...
2. joined the match.
3. has entered the game.

So if it finds all 3, then there will be duplicates, if you only check for "joined the match." and clear the text field whenever you update it, you won't see duplicates, otherwise if this file does have duplicates, then you could create an array and get distinct items or use LINQ.