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Loading and Exporting Formatting Data

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Once you've created your formatting file, you need to update the format data of the session by loading your files into the current session. PowerShell loads a predefined set of formats. Once the format data of the current session is updated, PowerShell uses that data to display the .NET objects associated with the views defined in the loaded formats. There's no limit to the number of formats that you can load into the current session. You can also export the format data in the current session back to a formatting file.

Loading format data

Formatting files can be loaded into the current session using the following methods:

  • You can import the formatting file into the current session from the command line. Use the Update-FormatData cmdlet as described in the following procedure.

  • You can create a module manifest that references your formatting file. Modules allow you to package your formatting files for distribution. Use the New-ModuleManifest cmdlet to create the manifest, and the Import-Module cmdlet to load the module into the current session. For more information about modules, see Writing a Windows PowerShell Module.

  • You can create a snap-in that references your formatting file. Use the System.Management.Automation.PSSnapIn.Formats to reference your formatting files. However, best practice recommendation is to use modules to package cmdlets and associated formatting and types files.

  • If you're invoking commands programmatically, you can add formatting files to the initial session state of the runspace where the commands are run. For more information, see the System.Management.Automation.Runspaces.SessionStateFormatEntry class.

When a formatting file is loaded, it's added to an internal list that PowerShell uses to choose the view used when displaying objects in the host. You can prepend your formatting file to the beginning of the list, or you can append it to the end of the list.

Knowing where your formatting file is added to this list is important.

  • If you're loading a formatting file that defines the only view for an object, you can use any of the methods described previously.

  • If you're loading a formatting file that defines a view for an object that has an existing view defined, it must be added to the beginning of the list. You must use the Update-FormatData cmdlet and prepend your file to the beginning of the list.

Storing Your Formatting File

You can store formatting files anywhere on disk. However, it's recommended that you store them in the same folder as your profile script.

Use the following command to determine the location of your profile script.

Split-Path -Path $PROFILE -Parent

Loading a format file

  1. Store your formatting file to disk.

  2. Run the Update-FormatData cmdlet using one of the following commands.

    If you're changing how an object is displayed, use the following command to add your formatting file to the front of the list.

    Update-FormatData -PrependPath PathToFormattingFile

    Use the following command to add your formatting file to the end of the list.

    Update-FormatData -AppendPath PathToFormattingFile

    Note

    Once format data has been loaded in a session it can't be removed. You must open a new session without the format data loaded.

Exporting format data

PowerShell includes format definitions for many .NET types. You can use the Get-FormatData cmdlet to view the format data that's loaded in the current session. You can export the format data for a type to a file using the Export-FormatData cmdlet.

The following commands export the format data for the System.Guid type to a file named System.Guid.format.ps1xml in the current directory.

Get-FormatData System.Guid | Export-FormatData -Path ./System.Guid.format.ps1xml
Get-Content ./System.Guid.format.ps1xml

<?xml version="1.0" encoding="utf-8"?>
<Configuration>
  <ViewDefinitions>
    <View>
      <Name>System.Guid</Name>
      <ViewSelectedBy>
        <TypeName>System.Guid</TypeName>
      </ViewSelectedBy>
      <TableControl>
        <TableHeaders />
        <TableRowEntries>
          <TableRowEntry>
            <TableColumnItems>
              <TableColumnItem>
                <PropertyName>Guid</PropertyName>
              </TableColumnItem>
            </TableColumnItems>
          </TableRowEntry>
        </TableRowEntries>
      </TableControl>
    </View>
  </ViewDefinitions>
</Configuration>

You can edit the exported file create a custom format definition for that type.