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Wednesday, December 5, 2012

How to find if a property in a custom object has a NULL NoteProperty

This was a bit of a different problem.  How to find if a property in a custom object has a NULL value.  The client had a collection of objects that they gathered from their environment with PowerShell.  They needed a way to find out if any of the NoteProperties had a NULL value.  I created the function below.  You send it the collection of objects you are interested in probing for a NULL property value and it will return the index number of the object in the collection that has one.

 

Function Find-NullProperty

{

    [cmdletbinding(HelpUri="http://get-help-jason-yoder.blogspot.com/2012/10/find-nullproperty.html")]

    Param (

        [Parameter(Mandatory=$True)]$Object

    )

    # Check to see if an object has any NULL values in

    # its properties.

 

    # Create an object to output to the calling statement.

    $Output = @()

 

    # Index number to return for to denote the instance of an object

    # (should multiple instances be sent) that the Null value if found

    # in.

    $Index = -1

 

    # Extract the names of the properties of the object.

    $PropNames = (($Object | GM) |

      Where {$_.MemberType -eq "NoteProperty"} |

      Select-Object -Property Name).Name

 

    #Cycle through each object

    ForEach ($Obj in $Object)

    {

        # Increment the Index.

        $Index++

 

        # Set to $True is a $Null value

        #is found in a property.

        $NullFound = $False

 

        ForEach ($Prop in $PropNames)

        {     

            If ($Obj.$Prop -contains $Null)

            {

                $NullFound = $True

            }    

        }

        If ($NullFound)

        {

            # Create the object to be returned.

            $Obj = New-Object -TypeName PSObject

           

            # Add object members

            $Obj | Add-Member `

                    -MemberType NoteProperty `

                    -Name "Index" `

                    -Value $Index

           

            # Send the object to the output array.

            $Output += $Obj 

        }

    }

    Write-Output $Output

<#

.SYNOPSIS

Indicates if an object has a property that is $NULL

 

.DESCRIPTION

Search through a collection of custom objects and returns the index

number of any instance that has a $NULL value in a NoteProperty

 

.PARAMETER Object

The Object, or collection of objects that may contain a NULL value

in a note property.

 

.EXAMPLE

Find-NullProperty $Object

 

 Index

 -----

     1

     2

 

Returns the index number of instance of a collection of object in which

a NoteProperty has a NULL value.

 

.NOTES

Provided without warranty or support.

Author: Jason Yoder.

#>

}

 

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