How do you list and filter files using LINQ?

Question

Anubhav Kumar · Answer

To list and filter files using LINQ, you can combine System.IO with LINQ queries to efficiently query file metadata (like name, size, extension, etc.).
Example: List All Files in a Directory
using System.IO;
using System.Linq;
string folderPath = @"C:\Uploads";
var files = Directory.GetFiles(folderPath)
    .Select(f =andgt; new FileInfo(f))
    .ToList();
Filter Examples Using LINQ
1. Filter by Extension
var pdfFiles = files
    .Where(f =andgt; f.Extension.Equals(".pdf", StringComparison.OrdinalIgnoreCase))
    .ToList();
2. Filter by File Size (e.g., files andgt; 1 MB)
var largeFiles = files
    .Where(f =andgt; f.Length andgt; 1 * 1024 * 1024) // andgt; 1MB
    .ToList();
3. Filter by Creation Date
var recentFiles = files
    .Where(f =andgt; f.CreationTime andgt;= DateTime.Today.AddDays(-7)) // last 7 days
    .ToList();
4. Filter by Name Pattern
var matchingFiles = files
    .Where(f =andgt; f.Name.Contains("report", StringComparison.OrdinalIgnoreCase))
    .ToList();
5. Combine Filters
var filtered = files
    .Where(f =andgt;
        f.Extension == ".txt" andand
        f.Length andlt; 500_000 andand
        f.CreationTime andgt; DateTime.Today.AddMonths(-1))
    .ToList();
Project to Custom DTO
var fileList = files.Select(f =andgt; new
{
    f.Name,
    f.Extension,
    SizeKB = f.Length / 1024,
    Created = f.CreationTime
}).ToList();
Bonus: Recursive File Listing
var allFiles = Directory.GetFiles(folderPath, "*.*", SearchOption.AllDirectories)
    .Select(f =andgt; new FileInfo(f))
    .ToList();

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How do you list and filter files using LINQ?

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1 Answers

Example: List All Files in a Directory

Filter Examples Using LINQ

1. Filter by Extension

2. Filter by File Size (e.g., files > 1 MB)

3. Filter by Creation Date

4. Filter by Name Pattern

5. Combine Filters

Project to Custom DTO

Bonus: Recursive File Listing

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