Parsing CSV file into Dictionary C#-CodePudding

I am looking to put the contents of a csv file into a dictionary:

public IDictionary<string, string> allContracts = new Dictionary<string, string>();

I am wondering how to do this as I have tried to find ways to use a csv parser however cannot find an effective method. I would like the code to run within:

public void CheckAvailability()
    {
       //this runs following a click even in a different section of my code

    }

Below is some sample data from the csv file I am looking to manipulate:

Vehicle ID,Customer ID,Booked Date,Booked_date_week_number,Number of Days Booked,BookingStatus
    135,CU1,1-Jul-19,27,0,Booked
    71,CU2,1-Jul-19,27,0,Booked
    73,CU3,1-Jul-19,27,0,Booked
    93,CU4,1-Jul-19,27,0,Booked
    137,CU5,1-Jul-19,27,0,Booked
    24,CU6,1-Jul-19,27,0,Booked

As you can see the column names are also included in the csv file, this is not an issue and is actually fundamental for the program I am creating.

Also please note I think I need to use a csv parser as the files being used are bigger than what's shown here, and so I don't want to encounter memory issues.

CodePudding user response：

I would approach this differently, by making a class that represents each row and, if needed, creating a dictionary from that

void Main()
{
    // See https://joshclose.github.io/CsvHelper/
    using (var reader = new StreamReader(@"C:\Temp\Bookings.csv"))
    using (var csv = new CsvReader(reader, CultureInfo.InvariantCulture))
    {
        var records = csv.GetRecords<Booking>();
        var dictionary = records.ToDictionary(r => r.VehicleID, r => r);    
    }
}

public enum BookingStatus
{
    Booked,
    // TOOD: Add other statuses
}
public class Booking
{
    [Name("Vehicle ID")]
    public int VehicleID { get; set; }
    [Name("Customer ID")]
    public string CustomerID { get; set; }
    [Name("Booked Date")]
    public DateTime BookedDate { get; set; }
    [Name("Booked_date_week_number")]
    public int BookedDateWeekNumber { get; set; }
    [Name("Number of Days Booked")]
    public int NumberOfDaysBooked { get; set; }
    [Name("BookingStatus")]
    public BookingStatus BookingStatus { get; set; }
}

Note that using the Vehicle ID as the key in your dictionary fails if the same vehicle ID appears more than once in the CSV file. You may find it more useful to create an array or list, which you could then query as needed with Linq, e.g. replace the line that creates the dictionary

var dictionary = records.ToDictionary(r => r.VehicleID, r => r);

with

var csvData = records.ToArray();

then you can do things like

var bookingsForVehicle = csvData.Where(d => d.VehicleID == 42);

The reason to call a method like .ToArray() or .ToList() is to avoid enumerating the results multiple times, which would cause the file to be parsed multiple times.