C# - Finding the common files between two directories

StickyMcGinty

Lads,

I'm have two directory paths, and i'm looking for a way to find the FileInfo objects that are common and the fileInfo objects that arn't between the two directories.

Does anyone know how to go about this? I'm looking for way way of finding the intersection of the two directories if you get me...

Thanks in advance!

fasty

What sort of container do you keep the FileInfo objects in? Are you using .Net 3.5? You might be able to use LINQ to do this very quickly.

StickyMcGinty

yup, using .NET 3.5

I'm keeping them in a FileInfo array so i can iterate through them quickly.

Then I want to be able to pass the common FileInfo objects accross methods.

I've googled LINQ and it looks like it might help me out, but I cant seem to design my own file comparer? I want to compare files by name, md5 hash and date modified.

Thankjs for the help so far fasty.

fasty

If they're in arrays, then you're sorted.

Given two arrays of FileInfo objects fileInfo1 and fileInfo2...

var folderDiff = (from f1 in fileInfo1 select f1.FullName).Except(from f2 in fileInfo2 select f2.FullName);

... you will be returned a container with all the differences based on filename.

I don't have time to test, but I'm I don't think you'll be able to compare FileInfo objects directly, since they'd have different paths, but you could use anonymous types to pull the filename, modified date etc in the select part of the LINQ expression.

StickyMcGinty

fasty, thank you so much man.

I'll give it a go anyway, the way i'm implementing it now is ridiculously complicated, thanks again!

fasty

No worries! BTW, I just had a mess about and it's Intersect to see what's common between two LINQ expressions!

Excuse the quick and dirty sample full of static methods.

using System;
using System.IO;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace FileCompareWithLinq
{
    class Program
    {
        static FileInfo[] ListDirectory(string path)
        {
            return (new DirectoryInfo(path)).GetFiles();
        }

        static void Main(string[] args)
        {
            FileInfo[] fileList1 = ListDirectory("C:\\Path\\One\\Here");
            FileInfo[] fileList2 = ListDirectory("C:\\Path\\Two\\Here");

            var filediff = (from f1 in fileList1 select f1.Name).Intersect(from f2 in fileList2 select f2.Name);

            foreach (String s in filediff)
                Console.WriteLine(s);

            Console.ReadLine();
        }
    }
}

StickyMcGinty

cheers my man, just threw together the same myself and i re-searched the array to get the FileInfo object so I can perform any comparision I want.

This problem was kickin my ass all day too, so thanks again!

Ginger

For more LINQ stuff, download LINQPad (its free)

Allows to write quick and custom LINQ code very easily