modifying derived class values from base class

Question

Is it possible to have a method in a base class to modify a derived class' properties? I was thinking something like this:

public class baseclass
{
  public void changeProperties(string propertyName, string newValue)
  {
    try
    {
      this.propertyName = newValue;
    }
    catch
    {
      throw new NullReferenceException("Property doesn't exist!");
    }
  }
}

Answer 1

You can solve your problem via reflection, because this reference's type will be equal actual type, i.e. type of derived class:

Solution:

public class baseclass
{
    public void changeProperties(string propertyName, object newValue)
    {            
        var prop = GetType().GetProperty(propertyName);
        if (prop == null)
            throw new NullReferenceException("Property doesn't exist!");
        else
            prop.SetValue(this, newValue);
    }
}

Implementation:

public class Test : baseclass
{
    public int Age { get; set; }
}

class Program
{
    static void Main(string[] args)
    {
        var test = new Test();
        test.changeProperties("Age", 2);
    }
}