Mastering Windows PowerShell Scripting - Third Edition

Input object types

If a type is defined for the InputObject variable, the command will only work if the input pipeline contains that object type. An error will be thrown when a different object type is passed. The following example modifies the command to accept pipeline input from Get-Process; it expects objects of the System.Diagnostics.Process type only:

function Get-InputObject {    [CmdletBinding()]    param (        [Parameter(Mandatory, ValueFromPipeline)]        [System.Diagnostics.Process]$InputObject    )    process {        'Process name {0}' -f $InputObject.Name    }}