Introduction

Meziantou.Framework.FullPath provides the FullPath type: the absolute path of a file or a folder. It replaces the strings that applications usually pass around to represent paths.

A string can hold a relative path, which silently depends on the current directory, a path with a trailing separator or with .. segments, or a path that two parts of the code compare with a different case sensitivity. A FullPath cannot: it is resolved and normalized when it is created, and it compares paths the same way everywhere.

What you can do with it

• Create paths from strings, from FileInfo and DirectoryInfo, from the current directory, the temporary folder and the special folders, and combine them with the / operator. See Creating paths.
• Read and change the parts of a path: the name, the extension, the parent folder. See Names, extensions and parents.
• Compare paths with the case sensitivity of the operating system or the one you choose, check that a path is inside a folder, and compute relative paths. See Comparing paths.
• Find a parent folder, such as the root of the Git repository. See Finding ancestors.
• Resolve symbolic links and get the canonical path of a file. See Symbolic links.
• Serialize paths to JSON, including with the System.Text.Json source generator. See Serialization.
• Use the Windows-specific features: reserved device names, extended-length paths, known folders. See Platform-specific features.
• Find the string paths to convert: the package includes an analyzer and code fixes. See Analyzer.

Principles

• Always absolute. FullPath.FromPath resolves a relative path against the current directory once, when the path is created, so later changes of the current directory do not change it.
• Normalized. . and .. segments are resolved and the trailing separator is removed, so two spellings of the same path give equal values.
• A string when you need one. FullPath converts implicitly to string, so you can pass it to File, Directory, FileStream and any other API that takes a path.
• Compared like the operating system does. Comparisons are ordinal. They ignore case on Windows, macOS, iOS and tvOS, and are case-sensitive elsewhere, unless you choose otherwise.
• An explicit empty value. default(FullPath) is FullPath.Empty, the absence of a path. It is never the current directory.
• Immutable. FullPath is a read-only struct: every method that changes a path returns a new value.

FullPath only computes paths: creating, combining or comparing paths never accesses the file system. The methods that do access it say so, such as CreateParentDirectory, CreateTempFile or the symbolic link methods.

Namespace

All the types are in the Meziantou.Framework namespace:

Next steps

• Getting started: install the package and write your first program.
• Analyzer: convert existing code that uses strings.