Learn More





DNN Community Blog

The Community Blog is a personal opinion of community members and by no means the official standpoint of DNN Corp or DNN Platform. This is a place to express personal thoughts about DNNPlatform, the community and its ecosystem. Do you have useful information that you would like to share with the DNN Community in a featured article or blog? If so, please contact .

The use of the Community Blog is covered by our Community Blog Guidelines - please read before commenting or posting.

4.6.0 A Sneak Peek (4) - IHydratable part 2

This is the fourth article on some of the features in the upcoming 4.6.0 release.  In this article I continue the discussion on the new interface - IHydratable.  In the previous blog I discussed the use of the new "Fill" method.  In this article I focus on the new property KeyID.

If you implement IHydratable on your Business Entity class (xxxInfo) then you will be required to add the KeyID property.  This property should be the property that maps to the Primary Key field in the corresponding database table.  In most situations (especially when you already have an entity class) you will already have a property that represents the primary key in your database.  In this scenario the KeyID will need to "wrap" the existing property. eg for Annoucnements whose primary key property is currently ItemID this would be:

        Public Property KeyID() As Integer Implements IHydratable.KeyID
                Return ItemId
            End Get
            Set(ByVal value As Integer)
                ItemId = value
            End Set
        End Property

So what does this new property do? Why is it included in this interface?  The answer lies in the new CBO method FillDictionary(Of T As IHydratable).  A Dictionary is a generic keyed collection which allows you to lookup the value based a key.  This new CBO class allows you to fill a generic dictionary in the same way as the other CBO methods allow you to return ArrayLists or generic Lists.

        Public Shared Function FillDictionary(Of T As IHydratable)(ByVal dr As IDataReader, ByRef objToFill As IDictionary(Of Integer, T)) As IDictionary(Of Integer, T)
            Dim objFillObject As T
            ' iterate datareader
            While dr.Read
                ' fill business object
                objFillObject = CreateObject(Of T)(dr)
                ' add to dictionary
                If objFillObject IsNot Nothing Then
                    objToFill.Add(objFillObject.KeyID, objFillObject)
                End If
            End While
            ' close datareader
            If Not dr Is Nothing Then
            End If
            Return objToFill
        End Function

The KeyID property provides a known property that can be used as the key to this Dictionary.

Ok - so that is why IHydratable has the KeyID.  So what?  Well the answer to this question is that a Dictionary is very useful when implementing caching in a Module.  In this scenario a developer could create a Business Layer method to fetch all the items, fill a Dictionary and cache the dictionary.  To retrieve an individual item now involves fetching the Dictionary from the cache, and using the KeyID to retrieve a specific item.

BTW - I will be providing more information on this interface and how it can help module developers in my OpenForce Europe talk on Module Development - so see you there.



There are currently no comments, be the first to post one.

Comment Form

Only registered users may post comments.


2sic Daniel Mettler (124)
Aderson Oliveira (15)
Alec Whittington (11)
Alex Shirley (10)
Andrew Nurse (30)
Anthony Glenwright (5)
Antonio Chagoury (28)
Ash Prasad (21)
Ben Schmidt (1)
Benjamin Hermann (25)
Benoit Sarton (9)
Beth Firebaugh (12)
Bill Walker (36)
Bob Kruger (5)
Brian Dukes (2)
Brice Snow (1)
Bruce Chapman (20)
Bryan Andrews (1)
cathal connolly (55)
Charles Nurse (163)
Chris Hammond (203)
Chris Paterra (55)
Clinton Patterson (28)
Cuong Dang (21)
Daniel Bartholomew (2)
Dave Buckner (2)
David Poindexter (3)
David Rodriguez (2)
Doug Howell (11)
Erik van Ballegoij (30)
Ernst Peter Tamminga (74)
Geoff Barlow (6)
Gifford Watkins (3)
Gilles Le Pigocher (3)
Ian Robinson (7)
Israel Martinez (17)
Jan Blomquist (2)
Jan Jonas (3)
Jaspreet Bhatia (1)
Jenni Merrifield (6)
Joe Brinkman (269)
John Mitchell (1)
Jon Henning (14)
Jonathan Sheely (4)
Jordan Coopersmith (1)
Joseph Craig (2)
Kan Ma (1)
Keivan Beigi (3)
Ken Grierson (10)
Kevin Schreiner (6)
Leigh Pointer (31)
Lorraine Young (60)
Malik Khan (1)
Matthias Schlomann (15)
Mauricio Márquez (5)
Michael Doxsey (7)
Michael Tobisch (3)
Michael Washington (202)
Mike Horton (19)
Mitchel Sellers (28)
Nathan Rover (3)
Navin V Nagiah (14)
Néstor Sánchez (31)
Nik Kalyani (14)
Peter Donker (52)
Philip Beadle (135)
Philipp Becker (4)
Richard Dumas (22)
Robert J Collins (5)
Roger Selwyn (8)
Ruben Lopez (1)
Ryan Martinez (1)
Salar Golestanian (4)
Sanjay Mehrotra (9)
Scott McCulloch (1)
Scott S (11)
Scott Wilkinson (3)
Scott Willhite (97)
Sebastian Leupold (80)
Shaun Walker (237)
Shawn Mehaffie (17)
Stefan Cullmann (12)
Stefan Kamphuis (12)
Steve Fabian (31)
Timo Breumelhof (24)
Tony Henrich (3)
Torsten Weggen (2)
Vicenç Masanas (27)
Vincent Nguyen (3)
Vitaly Kozadayev (6)
Will Morgenweck (37)
Will Strohl (163)
William Severance (5)
Try Evoq
For Free
Start Free Trial
a Demo
See Evoq Live
Need More Information?