vb.net textfile split by line to combobox

Question

vb.net textfile split by line to combobox

test
cool
username: username1
username: username2
username: username3
username: username4
username: username5
test

I want to extract all 5 username in add combobox

Answer 1

You could read the lines into an array, and then use a Regex to match the username lines.

Start with putting:

Imports System.IO
Imports System.Text.RegularExpressions

in the top of your code file, then you can use this code:

Dim FileLines() As String = File.ReadAllLines("path to file") 'Read all the lines of the file into a String array.

Dim RgEx As New Regex("(?<=username\:\s).+", RegexOptions.IgnoreCase) 'Declare a new, case-insensitive Regex.
For Each Line As String In FileLines 'Loop through every line.
    Dim m As Match = RgEx.Match(Line) 'Match the Regex pattern.
    If m IsNot Nothing AndAlso m.Success = True Then 'Have we found a match?
        ComboBox1.Items.Add(m.Value) 'Add the match to the ComboBox.
    End If
Next

The Regex is a class which is capable of matching substrings according to the specified pattern.

The pattern I used can be explained like this:

(?<=username\\:\\s).+

(?<=username\\: : Match a line starting with username: .

\\s : Match a space character (after username: ).

.+ : Match any character combination after that (which is your username, and what will be returned from m.Value ).

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Online code test: http://ideone.com/xnVkCc

Read more about Regex: MSDN - .NET Framework Regular Expressions

Hope this helps!

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EDIT:

If you want to match both username: and user name: you could try declaring the Regex with the following pattern instead:

Dim RgEx As New Regex("(?<=user(?:\s)?name\:\s).+", RegexOptions.IgnoreCase)