Merge Excel Sheets, Color Problem

using System;
using System.Collections.Generic;
//using System.Linq;
using System.Text;
using Microsoft.Office.Interop.Excel;
using System.Threading;
using System.Globalization;
using Office = Microsoft.Office.Core;
using Microsoft.Office.Core;


namespace TestExcel
{
    class Program
    {
        static void Main(string[] args)
        {
            Application xlApp = null;
            Workbook xlWorkBook = null;
            Workbook xlWorkBookChild = null;
            Workbooks xlWorkBooks = null;
            Worksheet xlWorkSheet = null;
            Sheets xlSheetChild;
            List<string> listaFicheiros = new List<string>();

            LanguageSettings xpto2;
            try
            {
                xlApp = new Application();


                Thread.CurrentThread.CurrentCulture = new CultureInfo("en-US");

                xlWorkBook = xlApp.Workbooks.Add(XlWBATemplate.xlWBATWorksheet);


                listaFicheiros.Add(@"\\filePath\file.xls");

                listaFicheiros.Add(@"\\filePath\file2.xls");


                foreach (string fileToParse in listaFicheiros)
                {
                    xlWorkBookChild = xlApp.Workbooks.Open(fileToParse, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing,
                                                    Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);

                    xlSheetChild = xlWorkBookChild.Sheets;

                    if (fileToParse.Contains("MIS_PPP_ALL"))
                    {
                        xlWorkBook.set_Colors(Type.Missing, xlWorkBookChild.get_Colors(Type.Missing));
                    }


                    foreach (Worksheet xlWorkSheetChild in xlSheetChild)
                    {
                        // Get the last sheet
                        xlWorkSheet = (Worksheet)xlWorkBook.Worksheets[xlWorkBook.Worksheets.Count];
                        //xlWorkBook.Worksheets.Add(Type.Missing, xlWorkSheet);


                        xlWorkSheetChild.Copy(Type.Missing, xlWorkSheet);



                    }

                    //xlWorkBook.set_Colors(Type.Missing, xlWorkBookChild.get_Colors(Type.Missing));
                    xlWorkBookChild.Close();
                }


                //Microsoft.Office.Interop.Excel.Workbook _ColorsType c =


                //xlWorkBook.Colors = Workbook_ColorsType.Colors;
                xlWorkBook.SaveAs(@"C:\Users\tiago.palhota\Desktop\Excel Testing\tiago", XlFileFormat.xlWorkbookDefault, Type.Missing, Type.Missing, Type.Missing, Type.Missing, XlSaveAsAccessMode.xlExclusive, Type.Missing, Type.Missing, Type.Missing, Type.Missing, Type.Missing);

                xlWorkBook.Close();
                xlApp.Quit();


                //Console.ReadLine();

            }
            catch (Exception ex)
            {

                throw;
            }
            finally
            {
                xlApp.Quit();

            }

        }
    }
}