PowerShell: Object Type, Properties, Methods

PowerShell commands input (parameter args) and output are all .NET objects. Each .NET object has a type, and members (“member” means properties and methods.). It's critical to understand this to master PowerShell.

• A command may output multiple objects.
• Each object has a type.
• The number of objects and type depends on the command parameter. For example, dir -name may return many objects but all of type System.String, but dir may return many objects, some of type System.IO.FileInfo, some of type System.IO.DirectoryInfo.

Find a Object's Type: Get-Member

To find the object type(s) of a command's output, pipe it to Get-Member. For each object type, Get-Member shows it only once in its output.

• gm is alias of Get-Member

examples:

"abc" | gm
# System.String

dir | gm
# System.IO.DirectoryInfo, System.IO.FileInfo

Get-Date | gm
# System.DateTime

Get Object Type programatically

To get a object type programatically, use .getType() method.

"abc".getType().ToString()
# "System.String"

if you have potentially multiple objects, pipe it to foreach.

dir | ForEach-Object {$_.getType().ToString()}
# System.IO.DirectoryInfo or System.IO.FileInfo

Get-Date | ForEach-Object {$_.getType().ToString()}
# System.DateTime

List Properties of a Given Object Type

dir -file | gm -MemberType Properties

List Methods of a Given Object Type

dir -file | gm -MemberType Method

Show Property Values of a Object

Show all properties and their values of a output object

Get-Date | select -Property *

dir -file | select -First 1 | select -Property *

• select is alias of Select-Object