Вы можете использовать OleDB в сочетании с реактивным двигателем:
using (var connection = new OleDbConnection(
"Provider=Microsoft.Jet.OLEDB.4.0;Data Source=\"" + directoryPath
+ "\";Extended Properties='text;HDR=Yes;FMT=Delimited(,)';"))
using (var command = new OleDbCommand(
"SELECT * FROM [" + fileName + "]", connection))
{
connection.Open();
using (var reader = command.ExecuteReader())
while (reader.Read())
...
}