SECTION_A 256
SECTION_B 344
SECTION_C 556

Dictionary<string, int> sectionIndex = new Dictionary<string, int>();
List<string> headers = new List<string>(); // fill these with readline

foreach(string header in headers) {
    var s = header.Split(new[]{' '});
    sectionIndex.Add(s[0], Int32.Parse(s[1]));
}

Dictionary<string, int> sectionIndex = new Dictionary<string, int>();
List<string> headers = new List<string>(); // fill these with readline

foreach(string header in headers) {
    var s = header.Split(new[]{' '});
    sectionIndex.Add(s[0], Int32.Parse(s[1]));
}

Dictionary<string, int> sectionIndex = new Dictionary<string, int>();
List<string> headers = new List<string>(); // fill these with readline

foreach(string header in headers) {
    var s = header.Split(new[]{' '});
    sectionIndex.Add(s[0], Int32.Parse(s[1]));
}

Dictionary<string, int> sectionIndex = new Dictionary<string, int>();
List<string> headers = new List<string>(); // fill these with readline

foreach(string header in headers) {
    var s = header.Split(new[]{' '});
    sectionIndex.Add(s[0], Int32.Parse(s[1]));
}

string dataRow = "";

try
{
    TextReader tr = new StreamReader("filename.txt");

    while (true)
    {
        dataRow = tr.ReadLine();
        if (dataRow.Substring(1, 8) != "SECTION_")
            break;
        else
            //Parse line for section code and line number and log values
            continue;
    }
    tr.Close();
}
catch (Exception ex)
{
    MessageBox.Show(ex.Message);
}