C# Online Compiler | .NET Fiddle

using System;
					
public class Program
{
	
	public class Product
	{
		public string Code { get;set;}
		public string Name { get;set;}
		public string Description { get;set;}
		public int Price { get;set;}
		
		public Product(string Code, string Name, string Description, int Price)
		{
			if(String.IsNullOrWhiteSpace(Code))
				throw new ArgumentNullException($"{nameof(this.Code)} cannot be empty");
			else
				this.Code =Code;
			
			if(String.IsNullOrWhiteSpace(Name))
				throw new ArgumentNullException($"{nameof(this.Name)} cannot be empty");
			else
				this.Name= Name;
			
			if(String.IsNullOrWhiteSpace(Description))
				throw new ArgumentNullException($"{nameof(this.Description)} cannot be empty");
			else
				this.Description = Description;
			
			if(Price <=0 )
				throw new ArgumentNullException($"{nameof(this.Price)} should be greater than 0");
			else
				this.Price= Price;
				
		}
		
		public void DisplayValues()
		{
			Console.WriteLine($"{nameof(this.Code)} - {this.Code}");
			Console.WriteLine($"{nameof(this.Name)} - {this.Name}");	
			Console.WriteLine($"{nameof(this.Description)} - {this.Description}");
			Console.WriteLine($"{nameof(this.Price)} - {this.Price}");
		}
	}
	
	public static void Main()
	{
		try
		{
			Console.WriteLine("With null value");
			Product prod1 = new Product(null, null,null,2);
			prod1.DisplayValues();
		}
		catch(Exception e)
		{
			Console.WriteLine(e.Message);
		}
							  
		Console.WriteLine("\nWithout null values");
		
		Product prod2 = new Product("640", "Nokia 640 XL","Nokia 640 XL LTE",15000);
		prod2.DisplayValues();
		
		
		
	}
}

 
using System;
                    
public class Program
{
    
    public class Product
    {
        public string Code { get;set;}
        public string Name { get;set;}
        public string Description { get;set;}
        public int Price { get;set;}
        
        public Product(string Code, string Name, string Description, int Price)
        {
            if(String.IsNullOrWhiteSpace(Code))
                throw new ArgumentNullException($"{nameof(this.Code)} cannot be empty");
            else
                this.Code =Code;
            
            if(String.IsNullOrWhiteSpace(Name))
                throw new ArgumentNullException($"{nameof(this.Name)} cannot be empty");
            else
                this.Name= Name;
            

Cached Result

Площадь первого прямоугольника равна 600, площадь второго прямоугольника равна 1035