Prevent saving properties in sitecore with custom validator in C#

Recently I had a requirement that when under certain conditions a Sitecore field should become readonly. To accomplish this requirement I created a new ReadOnlyWhenXYZValidator. The requirement stated that the validator should stop a user from saving the item if the field had changed. Here is how I accomplished it.

What I decided to do was create a custom validator that can be applied to each property that should become readonly once a condition is met.

[Serializable]
public class ReadOnlyWhenXYZValidator : StandardValidator
{
    public ReadOnlyWhenXYZValidator()
        : base()
    {
    }

    public ReadOnlyWhenXYZValidator(SerializationInfo info, StreamingContext context)
        : base(info, context)
    {
    }

    public override string Name
    {
        get { 
            return Sitecore.StringUtil.GetString(this.Parameters["ValidatorName"], 
                                                 this.GetType().ToString()); }
    }

    protected override ValidatorResult GetMaxValidatorResult()
    {
        return GetFailedResult(ValidatorResult.Error);
    }

    protected override ValidatorResult Evaluate()
    {
        Item item = this.GetItem();
        // The following will need to be replaced with your own logic to 
        // retrieve if an item should be readonly...
        var isReadOnly= ShouldBeReadOnly(item.ID.Guid);
        if (isReadOnly)
        {
            bool propertyHasChanged = HasPropertyChanged();
            if (propertyHasChanged)
            {
                this.Text = String.Format(
                   "Field '{0}' is readonly and cannot be updated",
                   this.GetFieldDisplayName());

                // Fatal Error is required in order to prevent saving
                return ValidatorResult.FatalError;
            }  
        }
        this.Text = "Valid";
        return ValidatorResult.Valid;
    }

    /// <summary>
    /// Returns a value indicating if the property value has changed
    /// </summary>
    private bool HasPropertyChanged()
    {
        var value = GetControlValidationValue();
        var contentItem = Sitecore.Context.ContentDatabase.GetItem(GetItem().ID);
        if (contentItem == null)
        {
            return false;
        }

        var oldValue = contentItem[GetField().ID];
        //Check if current value is different from an old value
        return value != oldValue;
    }
}

Notice I am returning a ValidatorResult.FatalError. This is the only ValidatorResult that prevents a user from saving an item, so although it sounds over the top, is required.

Once complete, simply tell Sitecore to run the validator against the fields you wish to validate. This is done by firstly adding a new Validation Rule to System > Settings > Validation Rules > Field Rules or a sub folder of that.

Once added, simply navigate to your field definitions and, within the Validation Rules section, add your custom validator to each of the folllowing:

• Quick Action Bar
• Validate Button
• Validator Bar
• Workflow

Once complete load your items and you should find you can't save items that match the condition you have. I hope this helps. Don't forget to share this article if you found it helpful.