http://stackoverflow.com/questions/5382088/parsing-vb6-code-in-net

SO5382088.cs

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

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            string vb = @"
Select Case Fields(""blah"").Value
    Case ""Some value""
        Fields(""other blah"").List = Lists(""a list name"")
    Case ""Some value2""
        Fields(""other blah2a"").List = Lists(""a list name2a"")
        Fields(""other blah2b"").List = Lists(""a list name2b"")
    Case ""Some value3""
        Fields(""other blah3"").List = Lists(""a list name3"")
End Select

Select Case Fields(""foo"").Value
    Case ""Some value""
        Fields(""other foo"").List = Lists(""a list foo"")
    Case ""Some value2""
        Fields(""other foo2"").List = Lists(""a list foo2"")
    Case ""Some value3""
        Fields(""other foo3"").List = Lists(""a list foo3"")
End Select

";

            string patternSelectCase = @"
Select\s+Case\s+Fields\(""(?<CaseField>[\w\s]+)""\)\.Value
(?<Cases>.*?)
End\s+Select
";

            string patternCase = @"
Case\s+""(?<Case>[\w\s]+)""\s+
(?:Fields\(""(?<Target>[\w\s]+)""\)\.List\s*=\s*Lists\(""(?<Value>[\w\s]+)""\)\s+)*
";

    MatchCollection matches = Regex.Matches(vb, patternSelectCase, RegexOptions.IgnoreCase |
                                            RegexOptions.IgnorePatternWhitespace | RegexOptions.Singleline);

    Console.WriteLine(matches.Count);

    var data = new Dictionary<String, Dictionary<String, List<ListData>>>();
    foreach (Match match in matches)
    {
        var caseData = new Dictionary<String, List<ListData>>();
        string caseField = match.Groups["CaseField"].Value;
        string cases = match.Groups["Cases"].Value;

        MatchCollection casesMatches = Regex.Matches(cases, patternCase, RegexOptions.IgnoreCase |
                                                        RegexOptions.IgnorePatternWhitespace | RegexOptions.Singleline);
        foreach (Match caseMatch in casesMatches)
        {
            string caseTitle = caseMatch.Groups["Case"].Value;
            var targetCaptures = caseMatch.Groups["Target"].Captures.Cast<Capture>();
            var valueCaptures = caseMatch.Groups["Value"].Captures.Cast<Capture>();
            caseData.Add(caseTitle, targetCaptures.Zip(valueCaptures, (t, v) => new ListData
            {
                Target = t.Value,
                Value = v.Value
            }).ToList());
        }

        data.Add(caseField, caseData);
    }

            Console.WriteLine(data["foo"]["Some value2"].First().Value);

            Console.ReadKey();
        }
    }

    class ListData
    {
        public string Target { get; set; }
        public string Value { get; set; }
    }
}