using System;

using System.Collections.Generic;

using System.Linq;

​

public class alias{

   public double Alias_Entity_Alias_Type_Cd {get; set;}

   public double Alias_Pool_Cd {get; set;}

}

​

public class Program

{

    public static void Main()

    {

        double personAliasPoolForRelatedPerson = 0;

        double HNAMPersonIdCd = 0;

        List<alias> aliasList = new List<alias>();

        aliasList.Add(new alias(){Alias_Entity_Alias_Type_Cd = 1, Alias_Pool_Cd = 2});

        aliasList.Add(new alias(){Alias_Entity_Alias_Type_Cd = 3, Alias_Pool_Cd = 4});

        aliasList.Add(new alias(){Alias_Entity_Alias_Type_Cd = 5, Alias_Pool_Cd = 6});

        aliasList.Add(new alias(){Alias_Entity_Alias_Type_Cd = 3, Alias_Pool_Cd = 7});

        HNAMPersonIdCd = 3;

        personAliasPoolForRelatedPerson = aliasList.Find(alias => alias.Alias_Entity_Alias_Type_Cd == HNAMPersonIdCd).Alias_Pool_Cd;

        Console.WriteLine($"personAliasPoolForRelatedPerson = {personAliasPoolForRelatedPerson}");

        HNAMPersonIdCd = 5;

        personAliasPoolForRelatedPerson = aliasList.Find(alias => alias.Alias_Entity_Alias_Type_Cd == HNAMPersonIdCd)?.Alias_Pool_Cd ?? personAliasPoolForRelatedPerson;

        Console.WriteLine($"personAliasPoolForRelatedPerson = {personAliasPoolForRelatedPerson}");

    }

}