using System;

using System.Linq;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        List<NotaFiscal> notasExcel =  GetNotasExcel();

        List<NotaFiscal> notasConsisaNet =  GetNotasConsisaNet();

        List<string> chavesExcept = notasConsisaNet.Select(x => x.Chave).Except(notasExcel.Select(x=>x.Chave)).ToList();

        List<NotaFiscal> notasExcept = notasConsisaNet.Where(x => chavesExcept.Contains(x.Chave)).ToList();

        Console.WriteLine("Notas ConsisaNET:");

        notasConsisaNet.ForEach(x => Console.WriteLine(x.Chave +", "+ x.Emitente+", "+ x.Total.ToString("C2")));

        Console.WriteLine("".PadRight(50,'-'));

        Console.WriteLine("Notas Excel:");

        notasExcel.ForEach(x => Console.WriteLine(x.Chave +", "+ x.Emitente+", "+ x.Total.ToString("C2")));

        Console.WriteLine("".PadRight(50,'-'));

        chavesExcept.ForEach(x => Console.WriteLine("Chave está no Consisa e não está no excel: "+ x ));

        notasExcept.ForEach(x => Console.WriteLine("Objeto Nota Fiscal que está no Consisa e não está no excel: "+ x.Chave +", "+ x.Emitente+", "+ x.Total.ToString("C2")));

    }

    public static List<NotaFiscal> GetNotasExcel()

    {

        List<NotaFiscal> notas = new List<NotaFiscal>();

        notas.Add(new NotaFiscal(){ Chave = "123456ABC", Emitente = "Empresa A", Total = 10 });

        notas.Add(new NotaFiscal(){ Chave = "223456DEF", Emitente = "Empresa B", Total = 20 });

        notas.Add(new NotaFiscal(){ Chave = "423456JKL", Emitente = "Empresa D", Total = 40 });

        notas.Add(new NotaFiscal(){ Chave = "623456PQR", Emitente = "Empresa F", Total = 60 });

        notas.Add(new NotaFiscal(){ Chave = "723456STU", Emitente = "Empresa G", Total = 70 });

        notas.Add(new NotaFiscal(){ Chave = "823456VWX", Emitente = "Empresa H", Total = 80 });

        return notas;

    }

    public static List<NotaFiscal> GetNotasConsisaNet()

    {

        List<NotaFiscal> notas = new List<NotaFiscal>();

        notas.Add(new NotaFiscal(){ Chave = "123456ABC", Emitente = "Empresa A", Total = 10 });

        notas.Add(new NotaFiscal(){ Chave = "223456DEF", Emitente = "Empresa B", Total = 20 });

        notas.Add(new NotaFiscal(){ Chave = "323456GHI", Emitente = "Empresa C", Total = 30 });

        notas.Add(new NotaFiscal(){ Chave = "423456JKL", Emitente = "Empresa D", Total = 40 });

        notas.Add(new NotaFiscal(){ Chave = "523456MNO", Emitente = "Empresa E", Total = 50 });

        notas.Add(new NotaFiscal(){ Chave = "623456PQR", Emitente = "Empresa F", Total = 60 });

        notas.Add(new NotaFiscal(){ Chave = "723456STU", Emitente = "Empresa G", Total = 70 });

        notas.Add(new NotaFiscal(){ Chave = "823456VWX", Emitente = "Empresa H", Total = 80 });

        return notas;

    }

}

​

​

public class NotaFiscal

{

    public string Chave {get;set;}

    public string Emitente {get;set;}

    public decimal Total {get;set;}

}