Get collection of objects from CSV string and vise-versa

A generic class to get object collection from csv string. I would like to know if there's any better way?

Converter class

public class CsvConverter<T>:List<T> where T:class
{
    private readonly string _csvText;
    private readonly string _separetor;

    /// <summary>
    /// Get object collection from CSV string
    /// </summary>
    /// <param name="csvText">CSV string with Title</param>
    /// <param name="separator">CSV line separator</param>
    public CsvConverter(string csvText, string separator= "\r\n")
    {
        this._csvText = csvText;
        _separetor = separator;
        BuildObject();
    }

    /// <summary>
    /// Get CSV string from collection of objects
    /// </summary>
    /// <param name="collection">Pass collection of objects</param>
    public CsvConverter(IEnumerable<T> collection)
    {
        foreach (var item in collection)
        {
            this.Add(item);
        }
    }

    /// <summary>
    /// Create new Instance of T object
    /// </summary>
    /// <returns></returns>
    protected T GetObject()
    {
        return (T)Activator.CreateInstance(typeof(T),true);
    }

    /// <summary>
    /// Build object from CSV string to collection
    /// </summary>
    private void BuildObject()
    {
        if (!string.IsNullOrEmpty(_csvText))
        {
            //Get first line from CSV string, than split by comma to get column names
            var _csvLines = _csvText.Split(_separetor);
            var _columnName =_csvLines[0].Split(',');


            for (int i = 1; i < _csvLines.Length; i++)
            {
                var line = _csvLines[i].Split(',');

                T obj = GetObject();
                Type t = obj.GetType();
                PropertyInfo[] props = t.GetProperties();

                int colIndx = 0;
                foreach (string str in line)
                {
                    PropertyInfo find = props.First(x => x.Name == _columnName[colIndx]);
                    find.SetValue(obj, Convert.ChangeType(str,find.PropertyType),null);

                    //propertyInfo.SetValue(propertyInfo.PropertyType, line[0]);
                    colIndx++;
                }
                this.Add(obj);
            }
        }
        else
        {
            throw new System.NullReferenceException("No CSV string has passed in the parameter");
        }
    }

    /// <summary>
    /// Returns CSV string from collection of T object
    /// </summary>
    /// <returns>string</returns>
    public string GetCsvString()
    {
        StringBuilder sb = new StringBuilder();
        foreach (var item in this)
        {
            Type t = item.GetType();
            PropertyInfo[] props = t.GetProperties();
            string ln = "";
            foreach (PropertyInfo prp in props)
            {
                ln= ln+($"{prp.GetValue(item)},");
            }
            sb.AppendLine($"{ln.TrimEnd(',')}");
        }
        return sb.ToString();
    }
}

get collection of object from csv string

        var csv = await System.IO.File.ReadAllTextAsync("test.csv");
        List<TestC> csvBarcode = new CsvConverter<TestC>(csv.TrimEnd());

get csv string from collection of object

        CsvConverter<TestC> b = new CsvConverter<TestC>(list);
        return Content(b.GetCsvString());