Muokkaa

Jaa

about_Function_Provider

  • Artikkeli

Provider name

Function

Drives

Function:

Capabilities

ShouldProcess

Short description

Provides access to the functions defined in PowerShell.

Detailed description

The PowerShell Function provider lets you get, add, change, clear, and delete the functions and filters in PowerShell.

A function is a named block of code that performs an action. When you type the function name, the code in the function runs. A filter is a named block of code that establishes conditions for an action. You can type the name of the filter in place of the condition, such as in a Where-Object command.

The Function drive is a flat namespace that contains only the function and filter objects. Neither functions nor filters have child items.

The Function provider supports the following cmdlets, which are covered in this article.

Types exposed by this provider

Each function is an instance of the System.Management.Automation.FunctionInfo class. Each filter is an instance of the System.Management.Automation.FilterInfo class.

The Function provider exposes its data store in the Function: drive. To work with functions, you can change your location to the Function: drive (Set-Location Function:). Or, you can work from another PowerShell drive. To reference a function from another location, use the drive name (Function:) in the path.

Set-Location Function:

To return to a file system drive, type the drive name. For example, type:

Set-Location C:

You can also work with the Function provider from any other PowerShell drive. To reference a function from another location, use the drive name Function: in the path.

Note

PowerShell uses aliases to allow you a familiar way to work with provider paths. Commands such as dir and ls are now aliases for Get-ChildItem, cd is an alias for Set-Location. and pwd is an alias for Get-Location.

Getting functions

This command gets the list of all the functions in the current session. You can use this command from any PowerShell drive.

Get-ChildItem -Path Function:

The Function provider has no containers, so the above command has the same effect when used with Get-ChildItem.

Get-ChildItem -Path Function:

You can retrieve a function's definition by accessing the Definition property, as shown below.

(Get-Item -Path function:more).Definition

You can also retrieve a function's definition using its provider path prefixed by the dollar sign ($).

$function:more

To retrieve the definition for a function that has a dash (-) in the name, wrap the value after the dollar sign in curly braces.

${function:Clear-Host}

Getting selected functions

This command gets the man function from the Function: drive. It uses the Get-Item cmdlet to get the function. The pipeline operator (|) sends the result to Format-Table. The -Wrap parameter directs text that does not fit on the line onto the next line. The -Autosize parameter resizes the table columns to accommodate the text.

Get-Item -Path man | Format-Table -Wrap -Autosize

Working with Function provider paths

These commands both get the function named c:. The first command can be used in any drive. The second command is used in the Function: drive. Because the name ends in a colon, which is the syntax for a drive, you must qualify the path with the drive name. Within the Function: drive, you can use either format. In the second command, the dot (.) represents the current location.

PS C:\> Get-Item -Path Function:c:
PS Function:\> Get-Item -Path .\c:

Creating a function

This command uses the New-Item cmdlet to create a function called Win32:. The expression in braces is the script block that is represented by the function name.

New-Item -Path Function:Win32: -Value {Set-Location C:\Windows\System32}

You can also create a function by typing it at the PowerShell command line. For example, tpe Function:Win32: {Set-Location C:\Windows\System32}. If you are in the Function: drive, you can omit the drive name.

Deleting a function

This command deletes the more function from the current session.

Remove-Item Function:more

Changing a function

This command uses the Set-Item cmdlet to change the prompt function so that it displays the time before the path.

Set-Item -Path Function:prompt -Value {
  'PS '+ (Get-Date -Format t) + " " + (Get-Location) + '> '
  }

Rename a function

This command uses the Rename-Item cmdlet to change the name of the help function to gh.

Rename-Item -Path Function:help -NewName gh

Copying a function

This command copies the prompt function to oldPrompt, effectively creating a new name for the script block that is associated with the prompt function. You can use this to save the original prompt function if you plan to change it. The Options property of the new function has a value of None. To change the value of the Options property, use Set-Item.

Copy-Item -Path Function:prompt -Destination Function:oldPrompt

Dynamic parameters

Dynamic parameters are cmdlet parameters that are added by a PowerShell provider and are available only when the cmdlet is being used in the provider-enabled drive.

Options <[System.Management.Automation.ScopedItemOptions]>

Determines the value of the Options property of a function.

  • None: No options. None is the default.
  • Constant: The function cannot be deleted, and its properties cannot be changed. Constant is available only when you are creating a function. You cannot change the option of an existing function to Constant.
  • Private: The function is visible only in the current scope
  • (not in child scopes).
  • ReadOnly: The properties of the function cannot be changed except by using the -Force parameter. You can use Remove-Item to delete the function.
  • AllScope: The function is copied to any new scopes that are created.

Cmdlets supported

Using the pipeline

Provider cmdlets accept pipeline input. You can use the pipeline to simplify task by sending provider data from one cmdlet to another provider cmdlet. To read more about how to use the pipeline with provider cmdlets, see the cmdlet references provided throughout this article.

Getting help

Beginning in Windows PowerShell 3.0, you can get customized help topics for provider cmdlets that explain how those cmdlets behave in a file system drive.

To get the help topics that are customized for the file system drive, run a Get-Help command in a file system drive or use the -Path parameter of Get-Help to specify a file system drive.

Get-Help Get-ChildItem

Get-Help Get-ChildItem -Path function:

See also