Question

I have a base class that has an API that returns a DataTable based on identifiers,
And I need to have an object for each identifier.

I hate to work with datatables, so I wanted to write a mapping code,
that I only have to map the properties to the specific fields in the datatable.

Is there any faster way to do it rather than my exmaple?

Thanks.

public abstract class BaseClass<T> where T : BaseClass<T>
{
    protected abstract T MapObject(DataRow row);

    protected abstract int SomeIdentifier { get; }

    public IList<T> GetData()
    {
        return ConvertDataTableToGenericList(GetDataTableFromOtherSource(this.SomeIdentifier));
    }

    private IList<T> ConvertDataTableToGenericList(DataTable table)
    {
        IList<T> objectList = new List<T>();
        foreach (DataRow row in table.Rows)
        {
            objectList.Add(MapObject(row));
        }
        return objectList;
    }
}

public class DerivedClass : BaseClass<DerivedClass>
{
    public int ID { get; set; }

    protected override int SomeIdentifier
    {
        get { return 1; }
    }

    protected override DerivedClass MapObject(DataRow row)
    {
        return new DerivedClass()
        {
            ID = (int)row["ID"]
        };
    }
}

Answer 1

You could change your interface to work with IEnumerable<T> and yield return the results. The overall performance wouldn’t increase but you could start faster to process the result.

As a sample:

private IEnumerable<T> ConvertDataTableToGenericList(DataTable table)
{
    foreach (DataRow row in table.Rows)
    {
        yield return MapObject(row);
    }
}