Question

I have a csv file where each row is a different type of record. I am parsing the csv and want to store the rows (varied types of records) in various types of custom classes.

At each row i need to instantiate a different class based on the record type.

So taken from other reflection examples, I have the code below;

      Type type = Type.GetType("myNamespace." + className);
      object recordclass = Activator.CreateInstance(type);

so i have an object named recordclass of the correct type, but how do I use it?

all I really want to do is access the properties of the class and populate the row data, and then later add to a container class.

I guess im missing something about the runtime nature of reflection. Please help me connect the dots!

Hope that all makes sense!

TIA,
Gary

Answer 1

With the example you give you could cast your object to the actual type you need:

Type type = Type.GetType("myNamespace." + className);
object recordclass = Activator.CreateInstance(type);

var record = recordClass as ConcreteRecordType;
if(record != null)
    record.Name = csv["Name"];

Alternatively look into using a Factory to return populated record objects:

public class RecordFactory
{
    RecordBase ParseCsvRow(string[] columns)
    {
        const int typeDescriminatorColumn = 0;
        switch (columns[typeDescriminatorColumn])
        {
            case "RecordTypeA":
                return new RecordTypeA(columns[1], columns[2], ...);
            case "RecordTypeB":
                return new RecordTypeB(columns[1], columns[2], ...);
            default:
                throw new InvalidOperationException("Unexpected descriminator: " + columns[typeDescriminatorColumn]);
        }
    }
}