NAME
Add-Member
SYNOPSIS
Adds custom properties and methods to an instance of a Windows PowerShell object.SYNTAX
Add-Member [-MemberType] {AliasProperty | CodeProperty | Property | NoteProperty | ScriptProperty | Properties |
PropertySet | Method | CodeMethod | ScriptMethod | Methods | ParameterizedProperty | MemberSet | Event | Dynamic |All} [-Name]
[[-Value] [-TypeName
] [ ] Add-Member [-NotePropertyName]
[-NotePropertyValue] [-TypeName
] [ ] Add-Member [-NotePropertyMembers]
[[-Force] -InputObject [-PassThru] [-TypeName ] ] Add-Member -InputObject
[-PassThru] -TypeName [ ] DESCRIPTION
The Add-Member cmdlet lets you add members (properties and methods) to an instance of a Windows PowerShell object.
For instance, you can add a NoteProperty member that contains a description of the object or a ScriptMethod member that runs a script to change the object.To use Add-Member , pipe the object to Add-Member , or use the InputObject parameter to specify the object. Use
the MemberType parameter to specify the type of member that you want to add, use the Name parameter to assign a
name to the new member, and use the Value parameter to set the value of the member. The properties and methods that you add are added only to the particular instance of the object that you specify.Add-Member does not change the object type. To create a new object type, use the Add-Type cmdlet. You can also use
the Export-Clixml cmdlet to save the instance of the object, including the additional members, in a file. Then you
can use the Import-Clixml cmdlet to re-create the instance of the object from the information that is stored in
the exported file.Beginning in Windows PowerShell 3.0, Add-Member has new features that make it easier to add note properties to
objects. You can use the NotePropertyName and NotePropertyValue parameters to define a note property or use the
NotePropertyMembers parameter, which takes a hash table of note property names and values. Also, beginning in Windows PowerShell 3.0, the PassThru parameter, which generates an output object, is neededless frequently. Add-Member now adds the new members directly to the input object of more types. For more
information, see the PassThru parameter description.PARAMETERS
-Force [
Indicates that this cmdlet adds a new member even the object has a custom member with the same name. You cannot use the Force parameter to replace a standard member of a type. Required? false Position? named Default value False Accept pipeline input? False Accept wildcard characters? false] -InputObject
Specifies the object to which the new member is added. Enter a variable that contains the objects, or type a command or expression that gets the objects. Required? true Position? named Default value None Accept pipeline input? True (ByValue) Accept wildcard characters? false-MemberType
Specifies the type of the member to add. This parameter is required. The acceptable values for this parameter are:- NoteProperty
- AliasProperty
- ScriptProperty
- CodeProperty
- ScriptMethod
- CopyMethod
For information about these values, see PSMemberTypes Enumerationhttp://msdn.microsoft.com/en-us/library/window
s/desktop/system.management.automation.psmembertypes(v=vs.85).aspx (http://msdn.microsoft.com/en-us/library/win
dows/desktop/system.management.automation.psmembertypes(v=vs.85).aspx). Not all objects have every type of member. If you specify a member type that the object does not have, Windows PowerShell returns an error. Required? true Position? 0 Default value None Accept pipeline input? False Accept wildcard characters? false-Name
Specifies the name of the member that this cmdlet adds. Required? true Position? 1 Default value None Accept pipeline input? False Accept wildcard characters? false-NotePropertyMembers
Specifies a hash table or ordered dictionary of note property names and values. Type a hash table or dictionary in which the keys are note property names and the values are note property values. For more information about hash tables and ordered dictionaries in Windows PowerShell, see about_Hash_Tables. This parameter was introduced in Windows PowerShell 3.0. Required? true Position? 0 Default value None Accept pipeline input? False Accept wildcard characters? false-NotePropertyName
Specifies the note property name. Use this parameter with the NotePropertyValue parameter. This parameter is optional. This parameter was introduced in Windows PowerShell 3.0. Required? true Position? 0 Default value None Accept pipeline input? False Accept wildcard characters? false-NotePropertyValue
Specifies the note property value.Use this parameter with the NotePropertyName parameter. This parameter is optional.
This parameter was introduced in Windows PowerShell 3.0. Required? true Position? 1 Default value None Accept pipeline input? False Accept wildcard characters? false-PassThru [
Returns an object representing the item with which you are working. By default, this cmdlet does not generate any output.] For most objects, Add-Member adds the new members to the input object. However, when the input object is a
string, Add-Member cannot add the member to the input object. For these objects, use the PassThru parameter to
create an output object.In Windows PowerShell 2.0, Add-Member added members only to the PSObject wrapper of objects, not to the
object. Use the PassThru parameter to create an output object for any object that has a PSObject wrapper. Required? false Position? named Default value False Accept pipeline input? False Accept wildcard characters? false-SecondValue
Specifies optional additional information about AliasProperty , ScriptProperty , CodeProperty , or CodeMethod
members. If used when adding an AliasProperty, this parameter must be a data type. A conversion to the
specified data type is added to the value of the AliasProperty. For example, if you add an AliasProperty that
provides an alternate name for a string property, you can also specify a SecondValue parameter of System.Int32 to indicate that the value of that string property should be converted to an integer when accessed by usingthe corresponding AliasProperty.
You can use the SecondValue parameter to specify an additional ScriptBlock when adding a ScriptProperty member. In that case, the first ScriptBlock, specified in the Value parameter, is used to get the value of a variable. The second ScriptBlock, specified in the SecondValue parameter, is used to set the value of a variable. Required? false Position? 3 Default value None Accept pipeline input? False Accept wildcard characters? false-TypeName
Specifies a name for the type. When the type is a class in the System namespace or a type that has a type accelerator, you can enter the short name of the type. Otherwise, the full type name is required. This parameter is effective only when the input object is a PSObject . This parameter was introduced in Windows PowerShell 3.0. Required? true Position? named Default value None Accept pipeline input? False Accept wildcard characters? false-Value
Specifies the initial value of the added member. If you add an AliasProperty , CodeProperty , ScriptProperty
or CodeMethod member, you can supply optional, additional information by using the SecondValue parameter. Required? false Position? 2 Default value None Accept pipeline input? False Accept wildcard characters? falseThis cmdlet supports the common parameters: Verbose, Debug, ErrorAction, ErrorVariable, WarningAction, WarningVariable, OutBuffer, PipelineVariable, and OutVariable. For more information, see about_CommonParameters (https:/go.microsoft.com/fwlink/?LinkID=113216). INPUTS
System.Management.Automation.PSObject You can pipe any object type to this cmdlet.OUTPUTS
None or System.ObjectWhen you use the PassThru parameter, this cmdlet returns the newly-extended object. Otherwise, this cmdlet
does not generate any output.NOTES
* You can add members only to PSObject objects. To determine whether an object is a PSObject object, use the
"is" operator. For instance, to test an object stored in the $obj variable, type `$obj -is [PSObject]`.
The names of the MemberType , Name , Value , and SecondValue parameters are optional. If you omit the
parameter names, the unnamed parameter values must appear in this order: MemberType , Name , Value , and
SecondValue . If you include the parameter names, the parameters can appear in any order.You can use the $this automatic variable in script blocks that define the values of new properties and
methods. The $this variable refers to the instance of the object to which the properties and methods are being
added. For more information about the $this variable, see about_Automatic_Variables.
*
Example 1: Add a note property to a PSObject
PS C:\>$A = dir c:\ps-test\test.txt
PS C:\> $A | Add-Member -NotePropertyName Status -NotePropertyValue Done
PS C:\> $A | Add-Member Status Done
PS C:\> $A.StatusDone
These commands add the Status note property with a value of "Done" to the FileInfo object that represents the Test.txt file.The first command uses the Get-ChildItem cmdlet (alias = "dir) to get the Test.txt file. It saves it in the $a
variable.The second and third commands add the note property to the object in $a. The third command omits the optional
parameter names, so the parameter values must be in the correct Name-Value order. These commands are equivalent
and can be used interchangeably.The fourth command uses dot notation to get the value of the Status property of the object in $a. As the output
shows, the value is "Done".Example 2: Add an alias property to a PSObject
PS C:\>$A = dir c:\ps-test\test.txt
PS C:\> $A | Add-Member -MemberType AliasProperty -Name FileLength -Value Length
PS C:\> $A.FileLength2394
These commands add the FileLength alias property to the object that represents the Test.txt file. The new property is an alias for the Length property.The first command use the Get-ChildItem cmdlet (alias = "dir") to get the Test.txt file.
The second command adds the FileLength alias property. The third command uses dot notation to get the value of the new FileLength property.Example 3: Add a StringUse note property to a string
PS C:\>$A = "A string"PS C:\> $A = $A | Add-Member @{StringUse="Display"} -PassThru
PS C:\> $A.StringUseDisplay
These commands add the StringUse note property to a string. Because Add-Member cannot add types to String input
objects, the command uses the PassThru parameter to generate an output object. The last command in the example displays the new property. The command uses the NotePropertyMembers parameter, but omits the parameter name, which is optional. The value of the NotePropertyMembers parameter is a hash table. The key is the note property name, StringUse , and the value is the note property value, Display.Example 4: Add a script method to a string object
PS C:\>$A = "This is a string."
PS C:\>$A = Add-Member -InputObject $A -MemberType ScriptMethod -Name "PadBoth" -Value {$P =
$this.PadLeft($this.Length + 1); $p.PadRight($p.Length + 1)} -PassThru
PS C:\>$A.Padboth()
This is a string. These commands add the PadBoth script method to a string object.The first command creates a string and saves it in the $A variable.
The second command adds the Padboth script method to the object in the $A variable. The Value parameter defines
the new script method. It uses the PadRight and PadLeft methods of a string to add one space the left and one space to the right of the string.The Value parameter also uses the $This automatic variable, which represents the current object. The $This
variable is valid only in script blocks that define new properties and methods.The command includes the PassThru parameter, which directs Add-Member to return an instance of the object that
includes the new script property. By default, Add-Member adds members to PSObject s and does not generate any
output.The third command uses dot notation to call the new PadBoth script method on the object in the $A variable.
Example 5: Add an alias property to an event
PS C:\>$Event = Get-EventLog -LogName System -Newest 1
PS C:\>$Event.TimeWritten | Get-MemberTypeName: System.DateTime
Name MemberType Definition
---- ---------- ----------
Add Method System.DateTime Add(System.TimeSpan value) AddDays Method System.DateTime AddDays(double value) AddHours Method System.DateTime AddHours(double value) AddMilliseconds Method System.DateTime AddMilliseconds(double value) AddMinutes Method System.DateTime AddMinutes(double value)...PS C:\>Add-Member -InputObject $Event -MemberType AliasProperty -Name When -Value TimeWritten -SecondValue
System.StringPS C:\>$Event.When | Get-MemberTypeName: System.String
Name MemberType Definition
---- ---------- ----------
Clone Method System.Object Clone() CompareTo Method int CompareTo(System.Object value), int CompareTo(string strB) Contains Method bool Contains(string value) These commands add the When alias property to an event in the System event log. The event is an EventLogEntryobject that is returned by the Get-EventLog cmdlet.
The When alias property is an alias for the TimeWritten property of the object. The SecondValue parameter is used to specify that the property value should be converted to type System.String when accessed by using theAliasProperty . The TimeWritten property is a DateTime object.
The first command uses the Get-EventLog cmdlet to get the newest event in the System event log. It stores the
event in the $Event variable.
To demonstrate that the TimeWritten property is a DateTime type, the second command uses dot notation to get theTimeWritten property of that event and pipes it to the Get-Member cmdlet.
The third command uses the Add-Member cmdlet to add the When alias property to the object instance in the $Event
variable. The Name parameter assigns the name, When, and the Value parameter specifies that When is an alias for
the TimeWritten property. The SecondValue parameter indicates that the value that the When method returns should be cast to a System.String type. The fourth command uses dot notation to call the new When method. The command pipes the method value to theGet-Member cmdlet to confirm that it has returned a string.
Example 6: Copy all properties of an object to another
PS C:\>function Copy-Property ($From, $To)
{ foreach ($p in Get-Member -InputObject $From -MemberType Property)
{ Add-Member -InputObject $To -MemberType NoteProperty -Name $p.Name
-Value $From.$($p.Name) -Force $To.$($p.Name) = $From.$($p.Name)
} } This function copies all of the properties of one object to another object. The first command in the function declares the function name and lists its parameters.The ForEach loop uses the Get-Member cmdlet to get each of the properties of the From object. The commands within
the ForEach loop are performed in series on each of the properties.The Add-Member command adds the property of the From object to the To object as a NoteProperty. It uses the Force
parameter to add members with the same member name. The last command in the function gives the new property the same name as the original property.Example 7: Create a custom object
PS C:\>$Asset = New-Object -TypeName PSObject
PS C:\>$d = [ordered]@{Name="Server30";System="Server Core";PSVersion="4.0"}
PS C:\>$Asset | Add-Member -NotePropertyMembers $d -TypeName Asset
PS C:\>$Asset | Get-Member TypeName: Asset
Name MemberType Definition
---- ---------- ----------
Equals Method bool Equals(System.Object obj) GetHashCode Method int GetHashCode() GetType Method type GetType() ToString Method string ToString()Name NoteProperty System.String Name=Server30
PSVersion NoteProperty System.String PSVersion=4.0 System NoteProperty System.String System=Server Core This example creates the Asset custom object.The first command uses the New-Object cmdlet to create a PSObject . The command saves the PSObject in the $Asset
variable. The second command uses the [ordered] type accelerator to create an ordered dictionary of names and values. Thecommand saves the result in the $D variable.
The third command uses the NotePropertyMembers parameter of the Add-Member cmdlet to add the dictionary in the $D
variable to the PSObject . It uses the TypeName property to assign a new name, Asset, to the PSObject .
The fourth command sends the new Asset object in the $Asset variable to the Get-Member cmdlet. The output shows
that the object has a type name of "Asset" and the note properties that we defined in the ordered dictionary.RELATED LINKS
Online Version: http://go.microsoft.com/fwlink/?LinkId=821748Export-Clixml
Get-Member
Import-Clixml
New-Object