using System;

​

​

// originally raised as a problem in https://stackoverflow.com/questions/65737287/return-a-derived-object-from-a-generic-method

// solution to this problem has been posted here: https://dotnetfiddle.net/ct8w0a

public class Program

{

    public static void Main()

    {

        // This would be some string imported from a CSV file   

        var customerData = "Customer,1,Ford";       

        var personData = "Person,675,Henry,Ford";

        var customerImporter = new ImportData<CompanyMaster>();

        customerImporter.ImportDataFromFile(customerData);

        var personImporter = new ImportData<PersonMaster>();

        personImporter.ImportDataFromFile(personData);

    }

}

​

public class GenericRepository<TBase> 

    where TBase : EntityBase

{

    public void Insert(TBase entity)

    {

        //.. generic Insert to database

    }

}

​

public class ImportData<TBase>  

    where TBase : EntityBase

{

    GenericRepository<TBase> _genericRepository;

    CsvConverter<TBase> _converter;

    //ctor

    public void ImportDataFromFile(string data)

    {

        // convert the string data to TBase

        _genericRepository = new GenericRepository<TBase>();

        _converter = new CsvConverter<TBase>();

        var entity = _converter.ConvertTo(data);

        Console.WriteLine(entity);

    }

}

​

// originally raised as a problem in https://stackoverflow.com/questions/65737287/return-a-derived-object-from-a-generic-method

// solution to this problem has been posted here: https://dotnetfiddle.net/ct8w0a

​

public class CsvConverter<TBase> where TBase: EntityBase{

    public TBase ConvertTo(string someString)

    {

        if (someString.StartsWith("Customer"))

        {

            return GetCompany(someString);

        } 

        else return GetPerson(someString);

    }

    private CompanyMaster GetCompany(string companyString){

        return new CompanyMaster();

    }

    private PersonMaster GetPerson(string companyString){

        return new PersonMaster();

    }

​

}

​

​

public abstract class EntityBase

{

    public int Id { get; set; }

    public DateTime CreatedDate { get; set; }

}

​

public class CompanyMaster : EntityBase

{

    public string CompanyName { get; set; }

}

​

public class PersonMaster : EntityBase

{

    public string FirstName { get; set; }

    public string LastName { get; set; }

}