Hi

I like the idea of using these methods for building up validation errors and passing them back to the UI, but I'm finding things a little tricky.

I have created a validator class (inheriting from ValidatorBase) and overridden the ValidateEntityBeforeSave() method. In here I perform my validation, and for each validation error I call SetEntityFieldError(). However this in itself doesn't prevent the entity from being saved, so I also have to throw an ORMEntityValidationException after all this validation code if any errors occurred, to prevent the entity from being saved, but this feels a bit unnecessary. Is there a better technique? (I'm using the Adapter model).

Also, I want to display these errors in the UI, so I figured that I could catch the ORMEntityValidationException, grab the entity in question (which is a property of the exception) then interrogate the DataErrorInfoError/DataErrorInfoErrorsPerField properties, however they are protected. I could create a partial class for the entity and create some public properties which wrap these protected properties to make them accessible to the UI, but again this seems a bit of an unnecessary overhead.

Does anyone have experiences and advice for using these methods?

Thanks in advance

Andy

Hello,

throwing an exception allow you to know exactly what happend because in your ORMEntityValidationException you can defined a custom message and show it directly in your UI.

Hi

The problem is I want to return all of an entity's validation errors, and thought the SetEntityFieldError would be the way to go. This is my code:

        protected override void OnBeforeEntitySave()
        {
            bool isValid = true;

            if (Title == null)
            {
                SetEntityFieldError(
                    Fields[(int)DocumentFieldIndex.Title].Name,
                    "Title must be specified",
                    true);
                isValid = false;
            }
            if (Price < 0)
            {
                SetEntityFieldError(
                    Fields[(int)DocumentFieldIndex.Price].Name,
                    "Price must be a valid amount.",
                    true);
                isValid = false;
            }
            // ...etc...

            if (!isValid)
            {
                throw new ORMEntityValidationException("Document validation failure", this);
            }
        }

As you can see I'm building up a list of entity field errors, then throwing an exception if there were any, to prevent the save from going ahead.

In my UI I do something like this:

try
{
     Call busines tier save logic to save the entity
}
catch (ORMEntityValidationException eve)
{
    // Here I want to extract the errors in eve.EntityValidated.DataErrorInfoErrorsPerField
    // and display in a label, but that property is protected!
}

As mentioned in my previous post, I could extend the entity with a partial class that contains a new public property to expose what's in DataErrorInfoErrorsPerField, but this seems a bit unnecessary! Is there a better way of doing all this?

Thanks again

Andrew

Well, might be ignorant from me but can't you not build a string of messages, let's say pipe delimited, and then parse it (split it) out in UI and display messages, something like:

errror = message1|message2|message3

throw new ORMEntityValidationException(error,Me)

UI dim errors() as string = error.split("|"c)

I would have preferred to use the properties and methods already provided by the entity classes, but I can't understand why the LLBLGen team chose to make the DataErrorInfoError & DataErrorInfoErrorsPerField properties protected. Used in conjunction with the SetEntityError & SetEntityFieldError methods it seemed a good way of passing validation messages back to the UI tier.

Apologies, I've just realised that in my UI I can do the following to extract the errors via the IDataErrorInfo interface (assuming the same validation code as quoted in my earlier msg):

            catch (ORMEntityValidationException eve)
            {
                IDataErrorInfo dataError = (IDataErrorInfo)eve.EntityValidated;
                // do something with the field-level errors, e.g. dataError["Price"]
            }

Thanks for everyone's input though. This area of the LLBLGen documentation is a little vague (as is the .Net documentation on IDataErrorInfo - very little on the 'net either). Perhaps some better examples would be useful...

Andy