C# CSV Reader and Writer

Elegant and simple.

public bool ReadNextRecord()
{
    Fields = new List<string>();
    bool ColumnComlpete = false;
    bool inQuotes = false;

    _columnBuilder.Remove(0, _columnBuilder.Length);

    while(true)
    {
        string line = _streamReader.ReadLine();
        if(line == null)
        {
            if(inQuotes) throw new Exception("unexpected endof file in csv file");
            break;
        }

        // Iterate through every character in the line
        for (int i = 0; i < line.Length; i++)
        {
            char character = line[i];

            if (inQuotes)
            {
                if (character == '"')
                {
                    if (line.Length > i + 1)
                    {
                        if(line[i + 1] == '"')
                        {
                            _columnBuilder.Append(character);
                            i++;
                        }
                        else if(line[i + 1] == ',')
                        {
                            i++;
                            inQuotes = false;
                            ColumnComlpete = true;
                        }
                        else
                        {
                            throw new Exception("unexpected Quoter in csv file");
                        }
                    }
                    else
                    {
                        ColumnComlpete = true;
                    }
                }
                else
                {
                    _columnBuilder.Append(character);
                }
            }
            else
            {
                if (character == ',')
                {
                    ColumnComlpete = true;
                }
                else if (character == '"')
                {
                    inQuotes = true;
                }
                else
                {
                    _columnBuilder.Append(character);
                }
            }

            if (ColumnComlpete)
            {
                Fields.Add(TrimColumns ? _columnBuilder.ToString().Trim() : _columnBuilder.ToString());
                _columnBuilder.Remove(0, _columnBuilder.Length);
                ColumnComlpete = false;
            }
            if (line.Length <= i + 1 && line[i] == ',')
            {
                Fields.Add("");
            }
        }
        if(inQuotes)
        {
            _columnBuilder.Append(Environment.NewLine);
        }
        else
        {
            break;
        }
    }

    return Fields.Count != 0;
}

var file = new CsvFile(new CsvReader("hello,word,,1\r\nhello,,excel,2"));
    
new CsvWriter().Write(file, "D:\\01.csv");

// If we are not currently inside a column
if (!inColumn)
{
    // If the current character is a double quote then the column value is contained within
    // double quotes, otherwise append the next character
    switch (character)
    {
        case ',':
            Fields.Add(string.Empty);
            break;
        case '"':
            inQuotes = true;
            break;
        default:
            _columnBuilder.Append(character);
            break;
    }

    inColumn = true;
    continue;
}