ReadExcelFile.cs

using System;
using System.IO;

namespace SpreadsheetImporter
{
    class Program
    {
        static void Main(string[] args)
        {
            ReadFile(@"C:\temp\jam2.xls");
            Console.ReadLine();
        }

        private static void ReadFile(string filePath)
        {
            try
            {
                Console.WriteLine($"Content of file is: {File.ReadAllText(filePath)}");
            }
            catch(IOException)
            {
                Console.WriteLine($"File {filePath} is already open, please close");
            }
            catch (Exception ex)
            {
                Console.WriteLine($"Something has gone wrong, see execption message: {ex.Message}");
            }
        }

    }
}