As an update, this is what I have done to make it work, but I'd still love to know if there is another way to do this and I'm barking up the wrong tree ...

So when my application starts, each module will look in my database store to find if there are any formats registered against entity properties in their namespace. For each entity and property, a method is called on my base entity (the one all IdeaBlade entities inherit from).   This method saves the property name and format required in a dictionary, and once per entity only adds a property interceptor action for the whole entity.  Then finally when a property on the entity is set, the action is called and it loops through the dictionary and adds verifiers for each of the properties that need formats.  Then the property interceptor action is removed.

Here is example code:  This would be called from Module.Initialize() (hard-coded values for example purposes only)

EntityBase entity = (EntityBase)Type.GetType("Courier").GetConstructor(new

Type[0] { }).Invoke(newobject[0] { });

entity.RegisterPropertyInterceptor("Code", "^[0-9]{4}$");

entity.RegisterPropertyInterceptor("AccountNumber", "^[A-Z]{3}[-][0-9]{2}$");

Then this is inside my EntityBase class:

#region Property Formatting

private Dictionary<string, PropertyFormatting> propertyFormatInterceptorList = new Dictionary<string, PropertyFormatting>();

internal class PropertyFormatting

{

private readonly string format;

private readonly string formatMessage;                

internal PropertyFormatting(string format, string formatMessage, bool verifierIsLoaded)

{

this.format = format;

this.formatMessage = formatMessage;

}

internal string Format { get { return this.format; } }

internal string FormatMessage { get { return this.formatMessage; } }

}

public void RegisterFormatPropertyInterceptor(string propertyName, string format, string formatMessage)

{

string entityPropertyInterceptorKey = String.Format("{0}", this.EntityAspect.Entity.ToString());

if (!propertyFormatInterceptorList.ContainsKey(propertyName))

{

if (this.EntityAspect.EntityMetadata.EntityProperties.Where(ep => ep.Name == propertyName).FirstOrDefault() != null)

{

propertyFormatInterceptorList.Add(propertyName, new PropertyFormatting(format, formatMessage, false));                           

List<PropertyInterceptorAction<PropertyInterceptorArgs<Entity, Object>>> actions = PropertyInterceptorManager.CurrentInstance

.GetActions<PropertyInterceptorArgs<Entity, Object>>(this.GetType(), null, PropertyInterceptorMode.BeforeSet)

.ToList();

if (actions.Where(a => a.Key == entityPropertyInterceptorKey).FirstOrDefault() == null)

{

PropertyInterceptorManager.CurrentInstance.AddAction(

new PropertyInterceptorAction<PropertyInterceptorArgs<Entity, Object>>(

this.GetType(),

null,

PropertyInterceptorMode.BeforeSet,

new Action<PropertyInterceptorArgs<Entity, Object>>(PropertyFormatInterceptor),

0.0,

entityPropertyInterceptorKey));

}

}

}

}

public void PropertyFormatInterceptor(PropertyInterceptorArgs<Entity, Object> args)

{

if (args.Instance.EntityAspect.EntityManager != null && args.Instance.EntityAspect.EntityManager.VerifierEngine != null)

{

// This should only be called once

foreach (var propertyFormatter in this.propertyFormatInterceptorList)

{

PropertyFormatting propertyFormatting = propertyFormatter.Value;

Verifier formatVerifier = new RegexVerifier(this.GetType(), propertyFormatter.Key, true, new NamedRegexPattern(propertyFormatting.FormatMessage, propertyFormatting.Format));

formatVerifier.VerifierOptions.ShouldExitOnBeforeSetError = true;

formatVerifier.VerifierOptions.ExecutionModes = IdeaBlade.Validation.VerifierExecutionModes.InstanceAndOnBeforeSetTriggers;

args.Instance.EntityAspect.EntityManager.VerifierEngine.AddVerifier(formatVerifier);

}

string entityPropertyInterceptorKey = String.Format("{0}", args.Instance.EntityAspect.Entity.ToString());

List<PropertyInterceptorAction<PropertyInterceptorArgs<Entity, Object>>> actions = PropertyInterceptorManager.CurrentInstance

.GetActions<PropertyInterceptorArgs<Entity, Object>>(this.GetType(), null, PropertyInterceptorMode.BeforeSet)

.ToList();

foreach (var action in actions.Where(a => a.Key == entityPropertyInterceptorKey))

{

PropertyInterceptorManager.CurrentInstance.RemoveAction(action);

}

}

}

#endregion

I have one final problem now, but it's to do with the UI (WPF) not IdeaBlade.  The problem is that a UI textbox is bound to the entity property.  Now I have the UI text box go red and the tooltip show the validation error message when the user types in the wrong thing, BUT the UI will still display what the user has typed in even though the actual entity property is something else.  So if anyone has any answers for this that would also be a help :)