DirectoryInfoExtensions

Extension methods for System.IO.DirectoryInfo that add directory hierarchy checks.

Definition

Namespace: Paragon Assembly: Paragon.dll

public static class DirectoryInfoExtensions

Methods

HasSubDirectory

Determines whether subDirectory is a descendant of parentDirectory by walking up the subDirectory's parent chain and comparing full paths.

public static bool HasSubDirectory(this DirectoryInfo parentDirectory, DirectoryInfo subDirectory)

Parameter	Type	Description
parentDirectory	DirectoryInfo	The potential parent directory
subDirectory	DirectoryInfo	The directory to check as a descendant

Returns: true if any ancestor of subDirectory matches parentDirectory; false otherwise.

Behavior:

• Trims trailing path separators (\, /) before comparison for cross-platform consistency

• Compares the FullName of each ancestor — this is a string equality check, not a filesystem-level check

• Starts from subDirectory.Parent (not subDirectory itself), so parent.HasSubDirectory(parent) returns false

Common Pitfalls

Case sensitivity varies by platform. FullName comparison is case-sensitive on Linux and case-insensitive on Windows. On case-sensitive filesystems, HasSubDirectory may return false for paths that differ only in casing.

Symlinks are not resolved. The comparison uses FullName as reported by DirectoryInfo, which does not resolve symbolic links. Two paths pointing to the same physical directory via symlinks will not match.

Examples

using System.IO;
using Paragon;

var assets = new DirectoryInfo("Assets");
var scripts = new DirectoryInfo("Assets/Scripts/Player");

bool isChild = assets.HasSubDirectory(scripts); // true
bool isSelf  = assets.HasSubDirectory(assets);  // false

See Also

• Extensions — extension system overview