How Can I Efficiently Use Directory.GetFiles() to Retrieve Multiple File Types?

Efficiently Fetching Multiple File Types Using Directory.GetFiles()

Need to retrieve files of different types from a directory efficiently? Directory.GetFiles() is a handy tool, but it has limitations when dealing with multiple file extensions. While using "|" or ";" as delimiters in the search pattern doesn't work, there are effective workarounds.

Solutions for .NET 4.0 and Above

For optimal performance in newer .NET versions, leverage Directory.EnumerateFiles() combined with LINQ:

<code class="language-csharp">var files = Directory.EnumerateFiles("C:\path", "*.*", SearchOption.AllDirectories)
    .Where(s => s.EndsWith(".mp3") || s.EndsWith(".jpg"));</code>

This approach first retrieves all files iteratively (improving performance compared to loading everything at once) and then filters the results using a lambda expression to keep only .mp3 and .jpg files.

Workaround for Older .NET Versions

If you're working with older .NET versions, you can adapt the solution using Directory.GetFiles():

<code class="language-csharp">var files = Directory.GetFiles("C:\path", "*.*", SearchOption.AllDirectories)
    .Where(s => s.EndsWith(".mp3") || s.EndsWith(".jpg"));</code>

This loads all files initially, then applies the same LINQ filter.

Important Notes

• Performance: While convenient, Directory.EnumerateFiles() might introduce a slight performance overhead in extremely large directories compared to a highly optimized custom solution. For performance-critical applications, manual iteration may be preferable.
• Path Syntax: Always enclose your directory path in double quotes ("C:path") to avoid errors.

This refined approach provides a clear and efficient solution for retrieving multiple file types using Directory.GetFiles() or its more efficient counterpart, Directory.EnumerateFiles(), depending on your .NET framework version.

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