In Umbraco 13, the media picker has some server-side validation to check whether a media has been selected if the property is marked as mandatory. When the user clicks the Save and publish button, a call is made to the

/umbraco/backoffice/umbracoapi/content/PostSave

, and part of the response looks like this:

json
{
  ...
  "ModelState": {
    "_Properties.image2.invariant.null.value": [
      "Value cannot be empty"
    ]
  }
  ...
}

Anyone know where this validation is handled? I haven't been able to find it anywhere in the code related to the media picker.

Possibly... https://github.com/umbraco/Umbraco-CMS/blob/release-13.3.2/src/Umbraco.Infrastructure/PropertyEditors/MediaPicker3PropertyEditor.cs

internal class MediaPicker3PropertyValueEditor : DataValueEditor, IDataValueReference

https://github.com/umbraco/Umbraco-CMS/blob/release-13.3.2/src/Umbraco.Core/PropertyEditors/DataValueEditor.cs

public virtual IValueRequiredValidator RequiredValidator => new RequiredValidator(_localizedTextService);

https://github.com/umbraco/Umbraco-CMS/blob/release-13.3.2/src/Umbraco.Core/PropertyEditors/Validators/RequiredValidator.cs

Great spot 👍 Now I just need to figure out why required validation doesn't work for my custom media picker (which extends

MediaPicker3PropertyEditor

😮