Resolving relative paths with wildcards in C#

Question

In C#, if I have a directory path and a relative file path with wildcard, e.g.

"c:\foo\bar" and "..\blah\*.cpp"

Is there a simple way to get the list of absolute file paths? e.g.

{ "c:\foo\blah\a.cpp", "c:\foo\blah\b.cpp" }

Background

There is a source code tree, where any directory can contain a build definition file. This file uses relative paths with wildcards to specify a list of source files. The task is to generate a list of absolute paths of all source files for each one of these build definition files.

Clypeus

System.IO.Directory.EnumerateFiles allows you to specify wildcards in the searchpattern param, see: msdn.microsoft.com/en-us/library/dd413233.aspx and will return absolute paths – Verdieverdigris

@Polity, System.ArgumentException: Search pattern cannot contain ".." to move up directories – Clypeus

Answer 1

You can get the absolute path first and then enumerate the files inside the directory matching the wildcard:

// input
string rootDir = @"c:\foo\bar"; 
string originalPattern = @"..\blah\*.cpp";

// Get directory and file parts of complete relative pattern
string pattern = Path.GetFileName (originalPattern); 
string relDir = originalPattern.Substring ( 0, originalPattern.Length - pattern.Length );
// Get absolute path (root+relative)
string absPath = Path.GetFullPath ( Path.Combine ( rootDir ,relDir ) );

// Search files mathing the pattern
string[] files = Directory.GetFiles ( absPath, pattern, SearchOption.TopDirectoryOnly );

Outplay

Path.GetFullPath() throws ArgumentException: Illegal characters in path, if the path contains any wildcard. – Clypeus

You're right, I updated my code so that the relative search pattern is first divided into directory- and file-information and afterwards the absolute path is determined – Outplay

It works! Even better, rather than string relDir = originalPattern.Substring ( 0, originalPattern.Length - pattern.Length ); We can use string relDir = Path.GetDirectoryName(originalPattern); – Clypeus

This works well, but only when no wildcards are used in the directory names of the relative path, like in the specific example provided by the question. – Preach

Answer 2

It's simple.

using System.IO;
      .
      .
      .
string[] files = Directory.GetFiles(@"c:\", "*.txt", SearchOption.TopDirectoryOnly);

Eachelle