C# Online Compiler | .NET Fiddle

using System;
					
public class Program
{
	public static void Main()
	{
		try
		{
			DoSomething();
		}
		catch(NotImplementedException e)
		{
			throw;
		}
	}
	
	public static void DoSomething()
	{
		throw new NotImplementedException("Something went wrong");
	}	
}

Compilation error (line 19, col 21): The type or namespace name 'DatItem' could not be found (are you missing a using directive or an assembly reference?)