Current Working Directory with PowerShell and .Net Calls

A question that occasionally comes up is, “Why doesn’t PowerShell change the [Environment]::CurrentDirectory while I navigate around the shell?”  This is always in the context of using a relative file path while working with the .Net framework.

One of the difficult aspects of this comes from the fact that PowerShell supports multiple pipelines of execution.  Although it’s not directly exposed yet, users will soon be able to suspend jobs to the background, and other concurrent tasks.

The current directory affects the entire process, so if we change the directory as you navigate around the shell, you risk corrupting the environment of jobs you have running in the background.

When you use filenames in .Net methods, the best practice is to use fully-qualified path names.  The Resolve-Path cmdlet makes this easy:

[C:\temp]
PS:37 > $reader = new-object System.Xml.XmlTextReader baseline.xml

[C:\temp]
PS:38 > $reader.BaseURI
file:///C:/Documents and Settings/<user>/baseline.xml

[C:\temp]
PS:37 > $reader = new-object System.Xml.XmlTextReader (resolve-path baseline.xml)

[C:\temp]
PS:38 > $reader.BaseURI
file:///C:/temp/baseline.xml

 

3 Responses to “Current Working Directory with PowerShell and .Net Calls”

  1. Burt Harris writes:

    Thanks for explaining the logic behind this Lee, it’s been really puzzling me.

    Resolve-path works great for cases where the file already exists, but fails when I’m trying to create a new file. It would be great if you’d provide an example with XmlTextWriter.

  2. Jeffrey Snover writes:

    PSMDTAG:FAQ: Current Directory – why doesn’t the PROCESS’s current directory change when I do a CD?

    Jeffrey Snover [MSFT]
    Windows PowerShell/Aspen Architect
    Visit the Windows PowerShell Team blog at: http://blogs.msdn.com/PowerShell
    Visit the Windows PowerShell ScriptCenter at: http://www.microsoft.com/technet/scriptcenter/hubs/msh.mspx

  3. PowerShell and Path | Sladescross's Blog writes:

    […] https://www.leeholmes.com/blog/2006/06/26/current-working-directory-with-powershell-and-net-calls/ […]

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