Muokkaa

Jaa

about_Functions_Advanced

  • Artikkeli

Short description

Introduces advanced functions that are a way to create cmdlets using scripts.

Long description

A cmdlet is a single command that participates in the pipeline semantics of PowerShell. This includes binary cmdlets, PowerShell advanced script functions, CDXML, and Workflows.

Advanced functions allow you create cmdlets that are written as a PowerShell function. Advanced functions make it easier to create cmdlets without having to write and compile a binary cmdlet. Binary cmdlets are .NET classes that are written in a .NET language such as C#.

Advanced functions use the CmdletBinding attribute to identify them as functions that act like cmdlets. The CmdletBinding attribute is similar to the Cmdlet attribute that's used in compiled cmdlet classes to identify the class as a cmdlet. For more information about this attribute, see about_Functions_CmdletBindingAttribute.

The parameters of the function are variables declared in the param() statement. You can use the optional [Parameter()] attribute alone or in combination with the [Alias()] attribute or any of the parameter validation attributes. For more information about how to declare parameters, see about_Functions_Advanced_Parameters.

The following example shows a function that accepts a name and then prints a greeting using the supplied name. Also notice that this function defines a name that includes a verb (Send) and noun (Greeting) pair like the verb-noun pair of a compiled cmdlet. However, functions aren't required to have a verb-noun name.

function Send-Greeting
{
    [CmdletBinding()]
    param(
        [Parameter(Mandatory=$true)]
        [string] $Name
    )

    process
    {
        Write-Host ("Hello " + $Name + "!")
    }
}

This function performs the work in the process block, which is equivalent to the ProcessingRecord method used in compiled cmdlets. The process block and the other named blocks are described in about_Functions_Advanced_Methods.

Advanced functions differ from compiled cmdlets in the following ways:

  • Advanced function parameter binding doesn't throw an exception when an array of strings is bound to a Boolean parameter.
  • The ValidateSet attribute and the ValidatePattern attribute can't pass named parameters.
  • Advanced functions can't be used in transactions.

See also