public partial class Foo
{
    [Key]
    public virtual int pk {get;set;}
    [Column("Foo")]
    public virtual string Name {get;set;}
}

var methTranslate = typeof(ObjectContext).GetMethod("Translate", new[] { typeof(DbDataReader), typeof(string), typeof(MergeOption) });

foreach (var className in classNames)
{
    // ...
    var translateGenericMethod = methTranslate.MakeGenericMethod(classType);
    // ...
    reader.NextResult();
    var enumerable = (IEnumerable)translateGenericMethod.Invoke(ObjectContext,
        new object[] { reader, entitySet.Name, MergeOption.AppendOnly });
}