C# type casting in class from own superclass

Question

The codes that I write from the source code of a project are below. I got that codes through a decompiler. Program is working good when I install normally but when I compile the source codes, it throws exception below.

Is this possible;

public abstract class ComPortSettingsBase
{
}

public class ComportSettings: ComPortSettingsBase
{
}

public abstract class Comport
{
    public ComPortSettingsBase Settings
    {
        get
        {
            return this.settings;
        }
        set
        {
            this.settings = value;
        }
    }
}

public class ComportSetup: Comport
{
    public ComportSettings Settings
    {
        get
        {
           return (ComPortSettings)base.Settings
        }
        set
        {
           // The problem is here.
           // Firts of all type casting is not valid. It causes type casting exception
           // If I remove the type casting it causes stackoverflow exception normally. 

           this.Settings = (ComPortSettingsBase)value;
        }
    }
}

Answer 1

Try this

public class ComportSetup: Comport
{
    public ComportSettings Settings
    {
        get
        {
           return (ComportSettingsBase)base.Settings
        }
        set
        {
           base.Settings = (ComPortSettingsBase)value;
        }