To access properties and methods of a parent class use the base keyword. So in your child class LoadData() method you would do this:
public class Child : Parent
{
public void LoadData()
{
base.MyMethod(); // call method of parent class
base.CurrentRow = 1; // set property of parent class
// other stuff...
}
}
Note that you would also have to change the access modifier of your parent MyMethod() to at least protected for the child class to access it.