How do read specific text from text file in VB.NET

Public Class Settings
    Private ReadOnly _sectionNameRegex As Regex = New Regex("(?<=\[).*(?=\])")
    Private ReadOnly _settingRegex As Regex = New Regex("(?<key>\w+)[^\w]=[^\w](?<value>\w+)")
    Private ReadOnly _settings As Dictionary(Of String, Dictionary(Of String, Object))

    Public Sub New(ByVal settingsFilePath As String)
        Dim settings = File.ReadLines(settingsFilePath)
        Dim sectionName = "default"

        For Each setting As String In settings

            If _sectionNameRegex.IsMatch(setting) Then
                sectionName = _sectionNameRegex.Match(setting).Value

                If Not _settings.ContainsKey(sectionName) Then
                    _settings.Add(sectionName, New Dictionary(Of String, Object)())
                End If
            Else

                If _settingRegex.IsMatch(setting) Then
                    Dim match = _settingRegex.Match(setting)
                    Dim key = match.Groups("key").Value
                    Dim value = match.Groups("value").Value

                    If _settings(sectionName).ContainsKey(key) Then
                        Throw New InvalidOperationException($"Duplicate key ({key}) found ({sectionName})")
                    End If

                    _settings(sectionName).Add(key, value)
                End If
            End If
        Next
    End Sub

    Public Function GetValueOrDefault(Of T)(ByVal section As String, ByVal key As String) As T
        If Not _settings.ContainsKey(section) Then
            Throw New KeyNotFoundException(section)
        End If

        If Not _settings(section).ContainsKey(key) Then
            Throw New KeyNotFoundException(key)
        End If

        Try
            Dim result As T = CType(_settings(section)(key), T)
            Return result
        Catch
            Return Nothing
        End Try
    End Function
End Class

public class Settings
    {
        private readonly Regex _sectionNameRegex = new Regex(@"(?<=\[).*(?=\])");
        private readonly Regex _settingRegex = new Regex(@"(?<key>\w+)[^\w]=[^\w](?<value>\w+)");
        private readonly Dictionary<string, Dictionary<string, object>> _settings;
        
        public Settings(string settingsFilePath){

            var settings = File.ReadLines(settingsFilePath);
            var sectionName = "default";
            foreach (string setting in settings){

                if (_sectionNameRegex.IsMatch(setting)) {

                    sectionName = _sectionNameRegex.Match(setting).Value;
                    if (!_settings.ContainsKey(sectionName)) {

                        _settings.Add(sectionName, new Dictionary<string, object>());
                    }
                }
                else {
                    if (_settingRegex.IsMatch(setting)) {

                        var match = _settingRegex.Match(setting);
                        var key = match.Groups["key"].Value;
                        var value = match.Groups["value"].Value;
                        if (_settings[sectionName].ContainsKey(key)) {
                            throw new InvalidOperationException($"Duplicate key ({key}) found ({sectionName})");
                        }
                        _settings[sectionName].Add(key,value);
                    }
                }
            }
        }

        public T GetValueOrDefault<T>(string section, string key) {
            if (!_settings.ContainsKey(section)) {
                throw new KeyNotFoundException(section);
            }

            if (!_settings[section].ContainsKey(key)){
                throw new KeyNotFoundException(key);
            }

            try {
                T result = (T) _settings[section][key];
                return result;
            }
            catch {
                return default(T);
            }
        }
    }