第一章(2):Nettiers實體層,抽像類EntityBaseCore

        ///EntityBaseCore:所有數據庫表實體類的父類(抽像類),定義了所有實體類必須要實現的行爲
        /// <summary>
        /// The base object for each database table entity.
        /// </summary>
        ///繼承接口IEntity(見第一章), INotifyPropertyChanged(向客戶端發出某一屬性值已更改的通知), IDataErrorInfo(提供用戶界面可以綁定的自定義錯誤信息), IDeserializationCallback(示在完成整個對象圖形的反序列化時通知類)
        [Serializable]//實體爲可序列化
        public abstract partial class EntityBaseCore : IEntity, INotifyPropertyChanged, IDataErrorInfo, IDeserializationCallback
        {
                #region Constructors
                /// <summary>
                /// Initializes a new instance of the <see cref="T:EntityBaseCore"/> class.
                /// </summary>
                protected EntityBaseCore()
                {
                }
              #endregion
            /// <summary>
            /// Determines whether the entity is being tracked by the Locator.
            /// </summary>
                [NonSerialized]
                private bool isEntityTracked = false;
                /// <summary>
                /// Suppresses Entity Events from Firing,
                /// useful when loading the entities from the database.
                /// </summary>
            [NonSerialized]
                private bool suppressEntityEvents = false;
                /// <summary>
                ///  Used by in place editing of databinding features for new inserted row.
                /// Indicates that we are in the middle of an IBinding insert transaction.
                /// </summary>
                [NonSerialized]
                protected bool bindingIsNew = true;
                ///<summary>
                ///  The actual hashcode of the entity.
                ///</summary>
                private string entityHashCode;
                /// <summary>
                ///        The name of the underlying database table.
                /// </summary>
                public abstract string TableName { get;}
                /// <summary>
                ///                The name of the underlying database table's columns.
                /// </summary>
                /// <value>A string array that holds the columns names.</value>
                public abstract string[] TableColumns {get;}
                //private bool _isDeleted = false;
                /// <summary>
                ///         True if object has been <see cref="MarkToDelete"/>. ReadOnly.
                /// </summary>
                [BrowsableAttribute(false), XmlIgnoreAttribute()]
                public virtual bool IsDeleted
                {
                        get { return this.EntityState == EntityState.Deleted; }
                }
                //private bool _isDirty = false;
                /// <summary>
                ///                Indicates if the object has been modified from its original state.
                /// </summary>
                /// <remarks>True if object has been modified from its original state; otherwise False;</remarks>
                [BrowsableAttribute(false), XmlIgnoreAttribute()]
                public virtual bool IsDirty
                {
                        get { return this.EntityState != EntityState.Unchanged; }
                }
                //private bool _isNew = true;
                /// <summary>
                ///                Indicates if the object is new.
                /// </summary>
                /// <remarks>True if objectis new; otherwise False;</remarks>
                [BrowsableAttribute(false), XmlIgnoreAttribute()]
                public virtual bool IsNew
                {
                        get { return this.EntityState == EntityState.Added; }
                        set { this.EntityState = EntityState.Added; }
                }
                //private EntityState state = EntityState.Unchanged ;
                /// <summary>
                ///                Indicates state of object
                /// </summary>
                /// <remarks>0=Unchanged, 1=Added, 2=Changed</remarks>
                [BrowsableAttribute(false), XmlIgnoreAttribute()]
                public abstract EntityState EntityState { get; set; }
                /// <summary>
                /// Accepts the changes made to this object.
                /// </summary>
                /// <remarks>
                /// After calling this method <see cref="IsDirty"/> and <see cref="IsNew"/> are false. <see cref="IsDeleted"/> flag remain unchanged as it is handled by the parent List.
                /// </remarks>
                public virtual void AcceptChanges()
                {
                        this.bindingIsNew = false;
                        EntityState = EntityState.Unchanged;
                        OnPropertyChanged(string.Empty);
                }
                ///<summary>
                ///  Revert all changes and restore original values.  To be implemented in concrete class.
                ///</summary>
                public abstract void CancelChanges();
                ///<summary>
                ///   Marks entity to be deleted.
                ///</summary>
                public virtual void MarkToDelete()
                {
                        if (this.EntityState != EntityState.Added)
                                this.EntityState = EntityState.Deleted ;
                }
                ///<summary>
                ///   Remove the "isDeleted" mark from the entity.
                ///</summary>
                public virtual void RemoveDeleteMark()
                {
                        if (this.EntityState != EntityState.Added)
                        {
                                this.EntityState = EntityState.Changed ;
                        }
                }
                /// <summary>
        /// Gets or sets the parent collection.
        /// </summary>
        /// <value>The parent collection.</value>
                [XmlIgnore]
                public abstract object ParentCollection{get;set;}
                #region Common Columns
                #endregion
                /// <summary>
                /// Object that contains data to associate with this object
                /// </summary>
                [NonSerialized]
                private object tag;
                /// <summary>
                ///     Gets or sets the object that contains supplemental data about this object.
                /// </summary>
                /// <value>Object</value>
                [System.ComponentModel.Bindable(false)]//指定成員不用於綁定
                [LocalizableAttribute(false)]
                [DescriptionAttribute("Object containing data to be associated with this object")]
                public virtual object Tag
                {
                        get
                        {
                                return this.tag;
                        }
                        set
                        {
                                if (this.tag == value)
                                        return;
                                this.tag = value;
                        }
                }
                /// <summary>
                /// Determines whether this entity is being tracked.
                /// </summary>
                [System.ComponentModel.Bindable(false)]
                [BrowsableAttribute(false), XmlIgnoreAttribute()]
                public bool IsEntityTracked
                {
                        get
                        {
                                return isEntityTracked;
                        }
                        set
                        {
                                isEntityTracked = value;
                        }
                }
                /// <summary>
                /// Determines whether this entity is to suppress events while set to true.
                /// </summary>
                [System.ComponentModel.Bindable(false)]
                [BrowsableAttribute(false), XmlIgnoreAttribute()]
                public bool SuppressEntityEvents
                {
                        get
                        {
                                return suppressEntityEvents;
                        }
                        set
                        {
                                suppressEntityEvents = value;
                        }
                }
                ///<summary>
                /// Provides the tracking key for the <see cref="EntityLocator"/>
                ///</summary>
                [XmlIgnoreAttribute(), BrowsableAttribute(false)]
                public abstract string EntityTrackingKey {        get; set; }
                ///<summary>
                /// Provides a unique HashCode throughout the lifetime of the entity.
                ///</summary>
                public override int GetHashCode()
                {
                        if (entityHashCode == null)
                                entityHashCode = Guid.NewGuid().ToString();
                        return entityHashCode.GetHashCode();
                }
                #region INotifyPropertyChanged Members
                /// <summary>
                /// Event to indicate that a property has changed.
                /// </summary>
                [field:NonSerialized]
                public event PropertyChangedEventHandler PropertyChanged;
                /// <summary>
                /// Called when a property is changed
                /// </summary>
                /// <param name="propertyName">The name of the property that has changed.</param>
                protected virtual void OnPropertyChanged(string propertyName)
                {
                        if (!suppressEntityEvents)
                        {
                                OnPropertyChanged(new PropertyChangedEventArgs(propertyName));
                        }
                }
                /// <summary>
                /// Called when a property is changed
                /// </summary>
                /// <param name="e">PropertyChangedEventArgs</param>
                protected virtual void OnPropertyChanged(PropertyChangedEventArgs e)
                {
                        if (!suppressEntityEvents)
                        {
                                //Validate the property
                         ValidationRules.ValidateRules(e.PropertyName);
                                if (null != PropertyChanged)
                                {
                                        PropertyChanged(this, e);
                                }
                        }
                }
                #endregion
                #region IDataErrorInfo Members
                /// <summary>
                /// Gets an error message indicating what is wrong with this object.
                /// </summary>
                /// <value></value>
                /// <returns>An error message indicating what is wrong with this object. The default is an empty string ("").</returns>
                public string Error
                {
                        get
                        {
                                string errorDescription = string.Empty;
                                if (!IsValid)
                                {
                                        errorDescription = ValidationRules.GetBrokenRules().ToString();
                                }
                                return errorDescription;
                        }
                }
                /// <summary>
                /// Gets the <see cref="T:String"/> with the specified column name.
                /// </summary>
                /// <value></value>
                public string this[string columnName]
                {
                        get
                        {
                                string errorDescription = string.Empty;
                                if (!IsValid)
                                {
                                         errorDescription = ValidationRules.GetBrokenRules().GetPropertyErrorDescriptions(columnName);
                                }
                                return errorDescription;
                        }
                }
              #endregion
              #region Validation
                [NonSerialized]
             private Validation.ValidationRules _validationRules;
                /// <summary>
                /// Returns the list of <see cref="Validation.ValidationRules"/> associated with this object.
                /// </summary>
                [XmlIgnoreAttribute()]
                protected Validation.ValidationRules ValidationRules
                {
                        get
                        {
                                if (_validationRules == null)
                                {
                                        _validationRules = new Validation.ValidationRules(this);
                                        //lazy init the rules as well.
                                        AddValidationRules();
                                }
                                return _validationRules;
                        }
                }
                /// <summary>
                /// Assigns validation rules to this object.
                /// </summary>
                /// <remarks>
                /// This method can be overridden in a derived class to add custom validation rules.
                ///</remarks>
                protected virtual void AddValidationRules()
                {
                }
                /// <summary>
                /// Returns a list of all the validation rules that failed.
                /// </summary>
                /// <returns><see cref="Validation.BrokenRulesList" /></returns>
                [XmlIgnoreAttribute()]
                public virtual Validation.BrokenRulesList BrokenRulesList
                {
                        get
                        {
                                return ValidationRules.GetBrokenRules();
                        }
                }
                /// <summary>
                /// Adds a rule to the list of validated rules.
                /// </summary>
                /// <param name="handler">The method that implements the rule.</param>
                /// <param name="propertyName">
                /// The name of the property on the target object where the rule implementation can retrieve
                /// the value to be validated.
                /// </param>
                public void AddValidationRuleHandler(Validation.ValidationRuleHandler handler, String propertyName)
                {
                   ValidationRules.AddRule(handler, propertyName);
                }
                /// <summary>
                /// Adds a rule to the list of validated rules.
                /// </summary>
                /// <remarks>
                /// </remarks>
                /// <param name="handler">The method that implements the rule.</param>
                /// <param name="args">
                /// A <see cref="Validation.ValidationRuleArgs"/> object specifying the property name and other arguments
                /// passed to the rule method
                /// </param>
                public void AddValidationRuleHandler(Validation.ValidationRuleHandler handler, Validation.ValidationRuleArgs args)
                {
                    ValidationRules.AddRule(handler, args);
                }
                /// <summary>
                /// Returns <see langword="true" /> if the object is valid,
                /// <see langword="false" /> if the object validation rules that have indicated failure.
                /// </summary>
                [Browsable(false)]
                public virtual bool IsValid
                {
                        get
                        {
                                Validate();
                                return ValidationRules.IsValid;
                        }
                }
                /// <summary>
                /// Force this object to validate itself using the assigned business rules.
                /// </summary>
                /// <remarks>Validates all properties.</remarks>
                public void Validate()
                {
                        ValidationRules.ValidateRules();
                }
                /// <summary>
                /// Force the object to validate itself using the assigned business rules.
                /// </summary>
                /// <param name="propertyName">Name of the property to validate.</param>
                public void Validate(string propertyName)
                {
                        ValidationRules.ValidateRules(propertyName);
                }
                /// <summary>
                /// Force the object to validate itself using the assigned business rules.
                /// </summary>
                /// <param name="column">Column enumeration representing the column to validate.</param>
                public void Validate(System.Enum column)
                {
                        Validate(column.ToString());
                }
              #endregion
                #region IDeserializationCallback Members
                        /// <summary>
                        /// Runs when the entire object graph has been deserialized.
                        /// </summary>
                        /// <param name="sender">The object that initiated the callback. The functionality for this parameter is not currently implemented.</param>
                        public void OnDeserialization(object sender)
                        {
                                if(!suppressEntityEvents)
                                {
                                        ValidationRules.Target = this;
                                        AddValidationRules();
                                }
                        }
                #endregion
        }
第一章(2):Nettiers實體層,抽像類EntityBaseCore

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