Reply To: Testing for property existance

I assume you’re using Set-StrictMode, if you’re getting errors when you try to access a non-existent property. By default, PowerShell just returns $null when you do that.

To test for the existence of a property, you can use the PSObject.Properties table:

$testObject = New-Object psobject -Property @{
    SomeProperty = 'SomeValue'
}

if ($testObject.PSObject.Properties['SomeProperty'])
{
    Write-Host "SomeProperty: $($testObject.SomeProperty)"
}

if ($testObject.PSObject.Properties['BogusProperty'])
{
    Write-Host "BogusProperty: $($testObject.BogusProperty)"
}

Edit: Get-Member works too, as Don mentioned:

if (Get-Member -InputObject $testObject -Name SomeProperty -MemberType Properties)
{
    Write-Host "SomeProperty: $($testObject.SomeProperty)"
}