由於專案需要，所以寫了這麼個方法。

最初是使用odbc，將csv作為一個數據源讀取，但後來發現效率差很多，而且讀取的資料型別有問題 

public static DataTable ReadCSVToTable(string filePath) {
            DataTable dt = new DataTable();
            if (filePath == string.Empty)
            {
                return dt;
            }
            using (StreamReader reader = new StreamReader(filePath, Encoding.Default))
            {
                DataColumn dc;
                string[] headerLine = reader.ReadLine().Split(new char[] { ',' });
                foreach (string column in headerLine)
                {
                    dc = new DataColumn(column);
                    dt.Columns.Add(dc);
                }

                while (reader.Peek() >= 0)
                {
                    DataRow row = dt.NewRow();
                    string line = reader.ReadLine();
                    string[] cellValues = line.Split(',');
                    for (int i = 0; i < cellValues.Length; i++)
                    {
                        if (string.IsNullOrEmpty(cellValues[i]))
                        {
                            row[i] = DBNull.Value;
                            continue;
                        }
                        row[i] = cellValues[i];
                    }
                    dt.Rows.Add(row);
                }
            }
            return dt;
        }