I think I have it mostly figured out now. Will just have to do some testing later on.

My code now adds a 'broken rule' to the business object if the delete will fail on a FK constraint.

       /// <summary>
        /// Checks for possible FK constraint violations prior to deleting a record
        /// If return is FALSE the delete is aborted
        /// </summary>
        /// <param name="entity"></param>
        /// <returns>bool</returns>
        protected override bool HookPreDeleteEntity(SQLTracGrpEntity entity)
        {

            bool bReturn = base.HookPreDeleteEntity(entity);

            if (bReturn)
            {
                // check to see if this type is used by a group or resource
                string sCommand = "[dbo].[sp_SQLTrac_CanDeleteGrp]";

                if ((int)this.ExecSprocScalar(sCommand, this.CreateParameter("@GrpID", (object)entity.GrpID, DbType.Int16)) == 0 )
                {
                    this.Rules.EntityPropertyDisplayName = "Group - "+entity.GrpName;

                    string sMsg = "Unable to delete " + this.Rules.EntityPropertyDisplayName;
                    sMsg += ".  This group is contains resource entries and/or child groups.";


                    this.Rules.AddErrorProviderBrokenRule("GrpName", sMsg);
                    
                    bReturn = false;
                }



            }

            return bReturn;
        }

So if the DeleteEntity() method returns a false, I can check the rules collection and pick up the message.

Tim