How to read Item's media field properties using SPE

Question

I have an item where we have a "Article Thumbnail" field(Media type) and an image is inserted from Media Library.

Now I need to check for Alt text in Item's media properties. I am trying with below script and finding an odd behavior. When I browse for Item's field, I see an empty alt. But when I do selection for that field, it is going to its media library item and fetching me the alt. So, how to get correct Item's Image alt ?

To be more clear, see the highlighted part (Alternate Text and Default Alternate Text)

Answer 1

You'll want to either cast the field to the proper field type or use the PSFields collection to access it for you.

Read more here.

Example: The following gets the home item of a site, accesses the HeroImage field and expands the Alt text.

$item = Get-Item -Path "master:" -ID "{961563FC-3445-4558-BF3A-06DF06BA6298}"
$item.PSFields.HeroImage.Alt

Update

Based on your revised requirements here is what I've learned.

When accessing the Alt field on the ImageField type the text is first extracted from the xml in the field followed by a fallback to the text on the media item. Doesn't appear that the Alt property provides a way to know whether or not it's the default value.

You could try something like the following:

$item = Get-Item -Path "master:" -ID "{961563FC-3445-4558-BF3A-06DF06BA6298}"
$detectedValue = $item.PSFields.HeroImage.Alt
$defaultValue = $item.PSFields.HeroImage.MediaItem["Alt"]

if($defaultValue -ne $detectedValue) {
    Write-Host "This has been overridden"
} else {
    Write-Host "This is the default value"
}

$rawValue = $item.PSFields.HeroImage.GetAttribute("alt")
if($detectedValue -ne $rawValue) {
    Write-Host "It's showing the default value"
}

"ABC" is stored in $rawValue and $detectedValue. If I cleared it out $detectedValue would match $defaultValue and $rawValue would be blank.

Answer 2

You can cast your item media field into ImageField in PowerShell and it will give you all the properties of this field. Here is the example code.

# Get the item using the ID
$item = Get-Item -Path "master:" -ID "{110D559F-DEA5-42EA-9C1C-8A5DF7E70EF9}"

# Pass your field name. In the example below it is Image and cast into the ImageField
$imageField = [Sitecore.Data.Fields.ImageField]$item.Fields["Image"] 

You will get all the properties like this.

If your field doesn't have the alt value set then you could go to the Image Item using the mediaid and get the value from there. Here is the example code.

# Get the actual Sitecore Image item by passing the mediaID (see your raw value of the image field)
$imageItem = Get-Item -Path master: -ID $imageField.mediaID

# Get the Alt value from the Image Item
$altValue = $imageItem.Fields["Alt"].Value

Hope this makes sense.