using System;

public class Program

{

    public static T Process<T>(Func<T> getresponse) where T : Parent, new()

    {

        try { return getresponse(); }

        catch { return new T() { I = 5 }; }

    }

    public static void Main()

    {

        var x = Process(() => new Child(9));

        Console.WriteLine(x.I.ToString());

        var y = Process(() => new Child(0));

        Console.WriteLine(y?.I.ToString() ?? "null");

    }

}

​

public class Parent

{

    public Parent() { }

    public Parent(int i) { I = i; }

    public int I { get; set; }

}

​

public class Child : Parent

{

    public Child() { }

    public Child(int j) : base(j) { if (j == 0) throw new ArgumentException("Helolo world"); }

}