CSLA .NET discussion

Re: How to make IsDirty working with private backing fields

RockfordLhotka — Wed, 28 Mar 2012 20:23:42 GMT

You may not have to modify CSLA as much as override OnPropertyChanging or OnPropertyChanged or perhaps best is PropertyHasChanged. That way you'll know that the property has changed and you can write code to compare with the original value or whatever other value you are storing.

Re: How to make IsDirty working with private backing fields

Miroslav Galajda — Wed, 28 Mar 2012 09:17:18 GMT

What I've previously described is business requirement that I can't do without. I need to intergraph reference as data and be able to detect if the object with a such reference has changed if there is set another reference.

Then it remains on me nothing more than to modify CSLA.

Re: How to make IsDirty working with private backing fields

JonnyBee — Tue, 27 Mar 2012 19:02:12 GMT

Hi.

I prefer to use a Key value for the "data" reference (usually a managed property).

The intergraph reference should not be part of the "undo" operation (and thus should not be viewed as a "data" property).
So my preference is to regard intergraph references as navigation property only to get additional values on that referenced object.

Also, this allows the Key value to be part of an Undo operation and after the undo operation you should reestablish/verify the intergraph reference based on the (possible reverted) Key value.

I believe the same goes if you have a remote data portal - intergraph references needs to be reestablished after the object graph is deserialized.
My projects are typically edge applications so I may be wrong about the remote data portal.

See also Using Csla 4 - Creating Business Objects section "Maintaining a reference" on page 36.

Re: How to make IsDirty working with private backing fields

Miroslav Galajda — Tue, 27 Mar 2012 18:25:10 GMT

I will describe the problem more closely.

The last example I used was just the modified version of yours.

The child property in my context is actually only a reference to a child in the object tree in another subtree.

So I have businessbindinglistbase in one subtree and I have reference to one of the items in that list in another part of the object tree.

And the behavior is that I can select any of the item from that child list and assign it to another child as a reference.

This is refered in the csla book as an Inter-Graph Reference.

All I want to do is use this style of reference while using the custom field data with previously described change detection.

Is it possible?

Thank you

Yours sincerely

Miroslav Galajda

Re: How to make IsDirty working with private backing fields

JonnyBee — Tue, 27 Mar 2012 16:35:11 GMT

That is not how IsDirty should be handled!

You should NOT change/set new child object into parent object and expect that to change "IsSelfDirty". When a child object implements "ITrackStatus" then IsDirty is propagated down to the child object itself.

If the child has IsNew then by default - Csla will consider the object as Dirty.

You are using the CustomFieldData that is NOT a supported addin in CSLA. The purpose of CustomFieldData is to change the IsDirty check to test foractual changes in fields. Ie Edit field with new value = dirty, edit field to old value = not Dirty.

Take f.ex: LazyLoading a child from a datasource (maybe even another data source) should not make the object tree dirty. Only if any of the property values is changed should the object tree become dirty.

Re: How to make IsDirty working with private backing fields

Miroslav Galajda — Tue, 27 Mar 2012 15:51:45 GMT

Thank you, but I don't know how would it help me.

Maybe we don't understand each other.

When I return to your example where PropertyGetSet class has a PropertyGetSetChild as Child.

What I want to do is that I change the child reference in the root object and I want to use it as general principle so I don't want to override IsDirty in each case to include each child.

var obj = PropertyGetSet.Fetch();

Assert.IsFalse(obj.IsDirty);
obj.Child = Child.NewChild(); // set the new child instance
Assert.IsTrue(obj.IsDirty);

So expected result is that obj detects the change without modifying IsDirty in the PropertyGetSet class (obj).

Re: How to make IsDirty working with private backing fields

JonnyBee — Tue, 27 Mar 2012 12:58:49 GMT

Hi.

Change to use this code

        public override bool IsSelfDirty
        {
            get
            {
                if (IsDeleted) return true;
 
                foreach (var registeredProperty in this.FieldManager.GetRegisteredProperties())
                {
                    // skip private backing fields 
                    if ((registeredProperty.RelationshipType & RelationshipTypes.PrivateField) == RelationshipTypes.PrivateField) 
                        continue;
 
                    // skip fields that have not been set yet
                    if (!FieldManager.FieldExists(registeredProperty) continue; 

                    // skip child objects that implement ITrackStatus
                    var fieldData = FieldManager.GetFieldData(registeredProperty);
                    if (fieldData.Value is ITrackStatus) continue; 
 
                    if (FieldManager.IsFieldDirty(registeredProperty))
                    {
                        return true;
                    }
                }
                return false;
            }
        }

and override IsSelfDirty in your business object to return

        public override bool IsSelfDirty
        {
            get { return base.IsSelfDirty || _child.IsDirty; }
        }

And you do not have to override IsDirty in your BO.:

Re: How to make IsDirty working with private backing fields

Miroslav Galajda — Tue, 27 Mar 2012 09:45:28 GMT

Well, finally I found the reason why your code is working well and my not.

I've incorporated the "Custom FieldData Classes" into my business layer from the article by Jason Bock: http://jasonbock.net/jb/Default.aspx?blog=entry.9cc70d85bef34e2b9a683ba82615f8a3.

The reason I've used this is to have the feature of determining whether the value was changed against the original value, e.g. you change the property several times to different values but finally you change it to the original value so the object should not indicate that IsDirty is true.

The main problem with the solution provided by Jason Bock, is that it uses the FieldData to check the dirty flag, and unfortunatelly properties implemented as private backing fields bypass the FieldManager.

There is overriden IsSelfDirty property as following:

    public override bool IsSelfDirty
    {
        get
        {
            var isSelfDirty = false;

            foreach(var registeredProperty in this.FieldManager.GetRegisteredProperties())
            {
                if(registeredProperty.RelationshipType.HasFlag(RelationshipTypes.Child) &&
                    this.FieldManager.IsFieldDirty(registeredProperty))
                {
                    isSelfDirty = true;
                    break;
                }
            }

            return isSelfDirty;
        }
    }

Original implementation, in CSLA, simply returns _isDirty field, which is correctly set to true.

Do you have any suggestions?

Thank you

Yours sincerely

Miroslav Galajda

Re: How to make IsDirty working with private backing fields

JonnyBee — Tue, 27 Mar 2012 05:24:01 GMT

Actually, there is 2 important procedures:

OnAddEventHooks
OnRemoveEventHooks

The purpose is to make the "parent" observe events in the child object and raise own events to notify UI / listeners of chenges.
This is necessary for the

ChildChanged event
BusyChanged
PropertyChanged
ListChanged (SL)
CollectionChanged
ChildChanged

events to work as expected.

It's necessary to make UI helpers like PropertyStatus / ObjectStatus / ReadWriteAuthorization to work as expected as they hook into one or more of these events.

Not exactly sure when these made it into the framework but they do exist in Csla 3.6 and forward.

Re: How to make IsDirty working with private backing fields

Tiago Freitas Leal — Tue, 27 Mar 2012 00:51:52 GMT

JonnyBee:

If your child is a BusinessObject then you need to make sure to call OnAddEventHooks when object is set and in OnDeserialized:

Hi Jonny,

Must have missed the OnAddEventHooks thing . When was it introduced? Reading code documentation it's not clear what its purpose. Can you shed some light on the subject?

Re: How to make IsDirty working with private backing fields

Miroslav Galajda — Mon, 26 Mar 2012 20:08:15 GMT

Hi,

Yes I have the problem with child object. Thanks I will try.

Yours sincerely

Miroslav Galajda

Re: How to make IsDirty working with private backing fields

JonnyBee — Mon, 26 Mar 2012 19:54:11 GMT

These tests run OK:

namespace MyTestProject
{
    public class PropertyGetSet : Csla.BusinessBase<PropertyGetSet>
    {
        public static readonly PropertyInfo<string> NameProperty = RegisterProperty<string>(c => c.Name,
                                                                                            RelationshipTypes.
                                                                                                PrivateField);

        private string _name = NameProperty.DefaultValue;

        public string Name
        {
            get { return GetProperty(NameProperty, _name); }
            set { SetProperty(NameProperty, ref _name, value); }
        }

        public static readonly PropertyInfo<PropertyGetSetChild> ChildProperty = RegisterProperty<PropertyGetSetChild>(c => c.Child, RelationshipTypes.PrivateField);
        private PropertyGetSetChild _child = ChildProperty.DefaultValue;
        public PropertyGetSetChild Child
        {
            get { return GetProperty(ChildProperty, _child); }
            set { SetProperty(ChildProperty, ref _child, value); }
        }

        public static PropertyGetSet Fetch()
        {
            return DataPortal.Fetch<PropertyGetSet>();
        }

        public override bool IsDirty
        {
            get { return base.IsDirty || _child.IsDirty; }
        }

        public override bool IsValid
        {
            get { return base.IsValid || _child.IsDirty; }
        }

        public void DataPortal_Fetch()
        {
            _child = PropertyGetSetChild.Fetch();
            OnAddEventHooks(_child);
            MarkClean();
        }

        protected override void OnDeserialized(System.Runtime.Serialization.StreamingContext context)
        {
            base.OnDeserialized(context);
            OnAddEventHooks(_child);
        }
    }

    public class PropertyGetSetChild : Csla.BusinessBase<PropertyGetSetChild>
    {
        public static readonly PropertyInfo<string> Name2Property = RegisterProperty<string>(c => c.Name2,
                                                                                            RelationshipTypes.
                                                                                                PrivateField);

        private string _name2 = Name2Property.DefaultValue;

        public string Name2
        {
            get { return GetProperty(Name2Property, _name2); }
            set { SetProperty(Name2Property, ref _name2, value); }
        }

        public static PropertyGetSetChild Fetch()
        {
            return DataPortal.FetchChild<PropertyGetSetChild>(null);
        }

        public void Child_Fetch(object criteria)
        {
            MarkClean();
        }
    }

    [TestClass]
    public class TestPropertyGetSet
    {
        [TestMethod]
        public void IsDirtyAfterPropertySet()
        {
            var obj = PropertyGetSet.Fetch();
            Assert.IsFalse(obj.IsDirty);
            obj.Name = "Miroslav";
            Assert.IsTrue(obj.IsDirty);
        }

        [TestMethod]
        public void IsDirtyAfterChildPropertySet()
        {
            var obj = PropertyGetSet.Fetch();
            Assert.IsFalse(obj.IsDirty);
            obj.Child.Name2 = "Miroslav";
            Assert.IsTrue(obj.IsDirty);
        }
    }
}

Re: How to make IsDirty working with private backing fields

JonnyBee — Mon, 26 Mar 2012 19:49:41 GMT

If your child is a BusinessObject then you need to make sure to call OnAddEventHooks when object is set and in OnDeserialized:

        public void DataPortal_Fetch()
        {
            _child = PropertyGetSetChild.Fetch();
            OnAddEventHooks(_child);
            MarkClean();
        }

        protected override void OnDeserialized(System.Runtime.Serialization.StreamingContext context)
        {
            base.OnDeserialized(context);
            OnAddEventHooks(_child);
        }

and override IsValid and IsDirty in the parent object:

        public override bool IsDirty
        {
            get { return base.IsDirty || _child.IsDirty; }
        }

        public override bool IsValid
        {
            get { return base.IsValid || _child.IsDirty; }
        }

Re: How to make IsDirty working with private backing fields

JonnyBee — Mon, 26 Mar 2012 19:28:19 GMT

This code runs as expected and makes the object dirty:

Re: How to make IsDirty working with private backing fields

Miroslav Galajda — Mon, 26 Mar 2012 18:08:40 GMT

Hi, this is exactly how I'm using it.

As I described the situation in the question, this API doesn't help and doesn't work that way.

I've debug version of CSLA 4.2 and it doesn't go through FieldManager so it can't store possible detected change.

Any other suggestions?

Thank you

Yours sincerely

Miroslav Galajda