Collections

San posted on Thursday, September 15, 2011

Hi, All

I am new to CSLA. Actually I can access child collections in parent page but how can i access child collection in child validation class.

E..g., I have a requirement based on previous data entered i have to run some validations.

Thanks,

San

Curelom replied on Thursday, September 15, 2011

I'm not quite sure what you are asking.  Could you provide some more details?

San replied on Thursday, September 15, 2011

Actually I have a requirement where it should trigger some validation rules.

for e.g., user can enter multiple records for a month.

Let say user entered 3 records for jan month, each record has a unique id.

On 1st record user entered age as 67 and on 2nd record there is a drop-down list which user picked 1st record unique id and entered age as 34. so I should throw and error message saying age is not equal.

Thanks!

San

Curelom replied on Thursday, September 15, 2011

I have done something similar to this. I had a scenario where the start date and end date values couldn't intersect. Don't know if my solution is the prefered way to do it. Structure of my objects is Transportation - TransportationRateList - TransportationRate. I made a object Business Rule like below. Note that it isn't a property business rule, but a rule to be used on the TransportationRate object. In the transportation Rate object I add the rule

public class DateSpansDoNotIntersectRule : BusinessRule {
        protected override void Execute(RuleContext context) {
            var target = (TransportationRate)context.Target;
            TransportationRateList targetList = target.Parent as TransportationRateList;
            DateSpan ds = new DateSpan(target.StartDate, target.EndDate);
 
            if (targetList != null) {
                //get list of datespans that we need to check
                var q = (from t in targetList
                         where t != target
                               && t.FreightMethod == target.FreightMethod
                               && t.Pallet == target.Pallet
                               && ds.Intersect(new DateSpan(t.StartDate, t.EndDate)) != null
                         select t).FirstOrDefault();
 
                if (q != null)
                    context.AddErrorResult("Effective Date spans cannot intersect.");
            }
        } 
    }

BusinessRules.AddRule(new DateSpansDoNotIntersectRule());

One of the problems with the PropertyStatus control is that it doesn't work for object Business Rules, only rules on properties.  

For me to get this to work I had to expose the accessiblity of Broken Rules Collection

        public IEnumerable<BrokenRule> BusinessObjectErrors {
            get {
                if (this.BrokenRulesCollection.Where(b => String.IsNullOrEmpty(b.Property)).Count() > 0) {
                    return this.BrokenRulesCollection.Where(b => String.IsNullOrEmpty(b.Property));
                }
                return null;
            }
        }
then I bound a column to the BusinessObjectErrors and set the data template for the column
   <DataTemplate>
        <ItemsControl ItemsSource="{Binding}" Margin="4" Padding="4">
            <ItemsControl.Template>
                <ControlTemplate TargetType="{x:Type ItemsControl}" >
                    <ItemsPresenter/>
                </ControlTemplate>
            </ItemsControl.Template>
            <ItemsControl.ItemTemplate>
                <DataTemplate>
                    <Border BorderBrush="{StaticResource BorderErrorBrush}" BorderThickness="1"
                            CornerRadius="10"
                            Background="{StaticResource BackgroundErrorBrush}">
                        <StackPanel Orientation="Horizontal" Background="Transparent">
                            <Image Source="{StaticResource Horizon_Image_Error}" ToolTip="{Binding Path=Description}" MaxHeight="12" MaxWidth="12"/>
                        </StackPanel>
                    </Border>
                </DataTemplate>
            </ItemsControl.ItemTemplate>
            <ItemsControl.ItemsPanel>
                <ItemsPanelTemplate>
                    <WrapPanel IsItemsHost="True" Orientation="Vertical" Margin="4" />
                    <!--Background="Yellow"-->
                </ItemsPanelTemplate>
            </ItemsControl.ItemsPanel>
        </ItemsControl>
    </DataTemplate>

 

You will also have to take into account property status changes.

San replied on Thursday, September 15, 2011

I really appreciate your reponse, but i would like to get previous data through collections.

Curelom replied on Thursday, September 15, 2011

You can't have business rules on the collections themselves.

San replied on Monday, September 19, 2011

Is there any other way to implement the functionality.

-San

Curelom replied on Monday, September 19, 2011

I haven't found another way except for what I detailed earlier in these posts.