.NET Framework 4.5.2+
.NET Framework 4.5.2+
.NET Standard 2.0+

PersistentBase.AfterConstruction() Method

Invoked when the current object is about to be initialized after its creation.

Namespace: DevExpress.Xpo

Assembly: DevExpress.Xpo.v20.2.dll

Declaration

public virtual void AfterConstruction()
Public Overridable Sub AfterConstruction

Remarks

Override this method in your PersistentBase descendants to add custom initialization logic to your persistent objects (see the code example below).

using DevExpress.Xpo;

...
public class MyDataObject : XPObject {
    public MyDataObject()
        : base() {
        // This constructor is used when an object is loaded from a persistent storage.
        // Do not place any code here.
    }

    public MyDataObject(Session session)
        : base(session) {
        // This constructor is used when an object is loaded from a persistent storage.
        // Do not place any code here.
    }

    public override void AfterConstruction() {
        base.AfterConstruction();
        // Place your initialization code here.
    }
}

The base AfterConstruction method implementation includes only functionality relevant for persistent objects associated with UnitOfWork. In essence, the default implementation marks the current object to be saved to a data store if both of the following conditions are met:

  • the current object is associated with a unit of work;
  • the current object is persistent (see XPTypeInfo.IsPersistent).

Examples

The example below demonstrated how to automatically populate the CreatedBy, CreatedOn, UpdatedBy, and UpdatedOn properties (audit columns) in a business class.

using DevExpress.Xpo;  
...

namespace YourSolutionName.BusinessObjects {  
    [DefaultClassOptions]  
    public class Contact : BaseObject {  
        public Contact(Session session)  
            : base(session) {  
        }  
        // Get a current active user
        User GetCurrentUser() {  
            return Session.GetObjectByKey<User>(SecuritySystem.CurrentUserId);  
        }  
        // Automatically fill the CreatedOn and CreatedBy columns 
        // when a current user creates a new Contact item.
        public override void AfterConstruction() {  
            base.AfterConstruction();  
            CreatedOn = DateTime.Now;  
            CreatedBy = GetCurrentUser();  
        }  
        // Automatically fill the UpdatedOn and UpdatedBy columns 
        // when a current user saves a modified Contact item.
        protected override void OnSaving() {  
            base.OnSaving();  
            UpdatedOn = DateTime.Now;  
            UpdatedBy = GetCurrentUser();  
        }

        protected override void OnChanged(string propertyName, object oldValue, object newValue) {
            base.OnChanged(propertyName, oldValue, newValue);
            if(!IsLoading) {
                switch(propertyName) {
                    // Run custom code when the "Email" property value is changed.
                    case nameof(Email):
                        UpdateContacts();
                        break;
                }
            }
        }

        User createdBy;  
        public User CreatedBy {  
            get { return createdBy; }  
            set { SetPropertyValue("CreatedBy", ref createdBy, value); }  
        }  
        DateTime createdOn;  
        public DateTime CreatedOn {  
            get { return createdOn; }  
            set { SetPropertyValue("CreatedOn", ref createdOn, value); }  
        }  
        User updatedBy;  
        public User UpdatedBy {  
            get { return updatedBy; }  
            set { SetPropertyValue("UpdatedBy", ref updatedBy, value); }  
        }  
        DateTime updatedOn;  
        public DateTime UpdatedOn {  
            get { return updatedOn; }  
            set { SetPropertyValue("UpdatedOn", ref updatedOn, value); }  
        }  
    }  
}  
See Also