Question

After retrieving data from a database I find myself doing this to create a domain object from the data in a DataRow (in this case, a DVD):

DataRow drDvd = myDataTable.Rows[0];
Dvd myDvd = new Dvd();
myDvd.id = drDvd.Field<long>("id");
myDvd.title = drDvd.Field<string>("title");
myDvd.description = drDvd.Field<string>("description");
myDvd.releaseDate = drDvd.Field<DateTime>("releaseDate");

As I soon felt of course, I am doing this over and over in pseudo-code:

myDvd.field = drDvd.Field<field.type>(field.name);

And I wondered if I could get it into a loop, however I’ve never used reflection before. The code I tried is this:

Dvd aDvd = new Dvd();
Type t = aDvd.GetType();
FieldInfo[] fields = t.GetFields();
foreach (FieldInfo fi in fields)
{
    fi.SetValue(aDvd, drDvd.Field<fi.FieldType>(fi.Name));
}

The problem is, as you may know, that the extension for the Field method of class DataRow does not accept a variable and needs to be explicitely filled in.

I am not that experienced in C# so I would like to pose the following two questions:

1. Is it good practice what I am trying to do?
2. How can I fill in the correct extension for Field<extension>(name)?

Answer 1

You’ll need to get the method info for the generic method, and call invoke on it. This way you can pass in the generic type to it programmatically. I’m on my phone, but it should look something like this:

MethodInfo mField = typeof(Dvd).GetMethod("Field");
MethodInfo genericMethod = mField.MakeGenericMethod(new Type[] { fi.FieldType });

GenericMethod.Invoke(aDvd,new Object[]{fi.Name});