using System;
using System.IO;

var filePath = @"C:\tmp\file.txt";
var file = new FileInfo(filePath); 

//file size
var fileSize = file.Length;

//file modification date
var dateChanges = file.LastWriteTime;

//file creation date
var creationDate = file.CreationTime;

//is read only file
var isReadOnly = file.IsReadOnly;

//file extension
var extension = Path.GetExtension(filePath);

//file name
var fileName = Path.GetFileName(filePath);

//file name without extension
var fileNameOnly = Path.GetFileNameWithoutExtension(filePath);

//file directory
var fileDir = Path.GetDirectoryName(filePath);

Console.WriteLine(fileSize);
Console.WriteLine(dateChanges);
Console.WriteLine(creationDate);
Console.WriteLine(isReadOnly);
Console.WriteLine(extension);
Console.WriteLine(fileName);
Console.WriteLine(fileNameOnly);
Console.WriteLine(fileDir);