using System;
using System.Collections.Generic;
using System.IO;
using System.Text.RegularExpressions;

class Sample {
  static void Main()
  {
    const string iniFile = @"test.ini";

    // INIファイルを読み込み、各セクション毎に表示する
    foreach (var section in ReadIni(iniFile)) {
      Console.WriteLine("[{0}]", section.Key);

      foreach (var pair in section.Value) {
        Console.WriteLine("  <{0}>='{1}'", pair.Key, pair.Value);
      }
    }
  }

  private static Dictionary<string, Dictionary<string, string>> ReadIni(string file)
  {
    using (var reader = new StreamReader(file)) {
      var sections = new Dictionary<string, Dictionary<string, string>>(StringComparer.Ordinal);
      var regexSection = new Regex(@"^\s*\[(?<section>[^\]]+)\].*$", RegexOptions.Singleline | RegexOptions.CultureInvariant);
      var regexNameValue = new Regex(@"^\s*(?<name>[^=]+)=(?<value>.*?)(\s+;(?<comment>.*))?$", RegexOptions.Singleline | RegexOptions.CultureInvariant);
      var currentSection = string.Empty;

      // セクション名が明示されていない先頭部分のセクション名を""として扱う
      sections[string.Empty] = new Dictionary<string, string>();

      for (;;) {
        var line = reader.ReadLine();

        if (line == null)
          break;

        // 空行は読み飛ばす
        if (line.Length == 0)
          continue;

        // コメント行は読み飛ばす
        if (line.StartsWith(";", StringComparison.Ordinal))
          continue;
        else if (line.StartsWith("#", StringComparison.Ordinal))
          continue;

        var matchNameValue = regexNameValue.Match(line);

        if (matchNameValue.Success) {
          // name=valueの行
          sections[currentSection][matchNameValue.Groups["name"].Value.Trim()] = matchNameValue.Groups["value"].Value.Trim();
          continue;
        }

        var matchSection = regexSection.Match(line);

        if (matchSection.Success) {
          // [section]の行
          currentSection = matchSection.Groups["section"].Value;

          if (!sections.ContainsKey(currentSection))
            sections[currentSection] = new Dictionary<string, string>();

          continue;
        }
      }

      return sections;
    }
  }
}

Imports System
Imports System.Collections.Generic
Imports System.IO
Imports System.Text.RegularExpressions

Class Sample
  Shared Sub Main()
    Const iniFile As String = "test.ini"

    ' INIファイルを読み込み、各セクション毎に表示する
    For Each section As KeyValuePair(Of String, Dictionary(Of String, String)) In ReadIni(iniFile)
      Console.WriteLine("[{0}]", section.Key)

      For Each pair As KeyValuePair(Of String, String) In section.Value
        Console.WriteLine("  <{0}>='{1}'", pair.Key, pair.Value)
      Next
    Next
  End Sub

  Private Shared Function ReadIni(ByVal file As String) As Dictionary(Of String, Dictionary(Of String, String))
    Using reader As New StreamReader(file)
      Dim sections As New Dictionary(Of String, Dictionary(Of String, String))(StringComparer.Ordinal)
      Dim regexSection As New Regex("^\s*\[(?<section>[^\]]+)\].*$", RegexOptions.Singleline Or RegexOptions.CultureInvariant)
      Dim regexNameValue As New Regex("^\s*(?<name>[^=]+)=(?<value>.*?)(\s+;(?<comment>.*))?$", RegexOptions.Singleline Or RegexOptions.CultureInvariant)
      Dim currentSection As String = String.Empty

      ' セクション名が明示されていない先頭部分のセクション名を""として扱う
      sections(String.Empty) = New Dictionary(Of String, String)()

      While True
        Dim line As String = reader.ReadLine()

        If line Is Nothing Then Exit While

        ' 空行は読み飛ばす
        If line.Length = 0 Then Continue While

        ' コメント行は読み飛ばす
        If line.StartsWith(";", StringComparison.Ordinal) Then
          Continue While
        Else If line.StartsWith("#", StringComparison.Ordinal) Then
          Continue While
        End If

        Dim matchNameValue As Match = regexNameValue.Match(line)

        If matchNameValue.Success Then
          ' name=valueの行
          sections(currentSection)(matchNameValue.Groups("name").Value.Trim()) = matchNameValue.Groups("value").Value.Trim()
          Continue While
        End If

        Dim matchSection As Match = regexSection.Match(line)

        If matchSection.Success Then
          ' [section]の行
          currentSection = matchSection.Groups("section").Value

          If Not sections.ContainsKey(currentSection) Then
            sections(currentSection) = New Dictionary(Of String, String)()
          End If

          Continue While
        End If
      End While

      Return sections
    End Using
  End Function
End Class