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Πρόσφατες Δημοσιεύσεις
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In this post you are going to see how you can use on more of eXpand powerfull features. 4 different ways for creating calculated runtime properties are avaliable. XPO way –>Using Code Take a note at the CreateCalculabeMember extension method at the code bellow public class CreateRuntimeCalculatedFieldController : ViewController { public override void CustomizeTypesInfo ( DevExpress . ExpressApp . DC . ITypesInfo typesInfo) { base . CustomizeTypesInfo (typesInfo); var classInfo = XafTypesInfo . XpoTypeInfoSource . XPDictionary . GetClassInfo ( typeof ( Customer )); Διαβάστε περισσότερα »...
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In this post I would like to present you with a very simple example on how to create a simple web service that access data from a database. Then we will create a consuming application that will consume the web service. I will use VS 2010 Ultimate edition...( read more )...
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ModelDifference module is one of the powerfull modules of eXpand . It really helps in managing your application models. Scenario Your application has been already distributed to your client and you no longer have access to the production database. Your client admin is responsible for that. But since development never stops as you know, you client asked for some model modification and some new application models (lets say 10) have been developed by your team and you want to sent them to the admin to update the application. eXpand IO module is the right one for the job Step1—Create a serialization graph to configure which objects/values you are going to export In order to create a serialization graph for an object type you have 1st to create a Serialization Configuration Διαβάστε περισσότερα »...
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Xaf provides a very easy to configure navigation system and in this post i will speak about expand approach to make Xaf’s navigation system behave better than the one provided by default. To enable eXpand extended navigation behaviour one can use the ViewShortcutProccesor attribute either at BO level or at View level as shown in the next image Now what this ViewShortcutProccesor can do to speed up your development? Navigate to a detailview using a ReadOnlyParameter the above readonly parameter taken from eXpand feature center and is defined as public class ExternalApplicationKeyParameter : ReadOnlyParameter { public ExternalApplicationKeyParameter () : base ( "ExternalApplicationKey" Διαβάστε περισσότερα »...
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Last week two security researchers, Thai Duong and Juliano Rizzo, have discovered a bug in the default encryption mechanism used to protect the cookies normally used to implement Forms Authentication in ASP.NET. Using their tool (the Padding Oracle Exploit Tool or POET), they can repeatedly modify an ASP.NET Forms Authentication cookie encrypted using AES and, by examining the errors Διαβάστε περισσότερα »...
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http://highscalability.com/blog/2010/9/5/hilarious-video-relational-database-vs-nosql-fanbois.html...
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Παρακάτω θα φτιάξουμε βήμα-βήμα ένα Notification box για το silverlight, χρησιμοποιώντας μία ελαφρώς παραλλαγμένη έκδοση του style που βρίσκεται ήδη στη νέα έκδοση Silverlight 4, που εισήγαγε το συγκεκριμένο control. Η λειτουργικότητα θα είναι επίσης ελαφρώς διαφορετική, αφήνοντας στην ευθύνη του silverlight control την λειτουργία του αυτόματου ελέγχου, για το αν υπάρχουν ή όχι notifications για τον χρήστη. Σκοπός είναι, καθώς θα καταγράφουμε βήμα βήμα την πορεία κατασκευής του control, θα καταλαβαίνουμε παράλληλα Διαβάστε περισσότερα »...
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DevExpress has the best support center I have ever seen, their Code Central really rocks and its fill with hundredths' of samples. One of them is is How to implement the MemberLevel security manually (for example, to deny the 'Read' access for declared properties of some business class, and allow access for the inherited properties eXpand has the above example as a module since its version 9 and you can use it by using the Xpand.ExpressApp.MemberLevelSecurity.dll assembly following the standard procedure for registering a xaf module. But in v10 we have boost it a little bit and we have make it conditional so now you can apply multiple Member Access Permissions to a member and by using the criteria member you can force the permission to be applied only to objects Διαβάστε περισσότερα »...
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Introduction In this tutorial blog post we will discover how easy it is to implement a simple puzzle game in Windows Phone 7 using the XNA 4.0 platform. The game consists of a single image, split randomly in 15 tiles (each of them having the same dimensions). The player has to move the tiles one by one (using the “empty” tile), attempting to recreate the original image. The starting Διαβάστε περισσότερα »...
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Given my previous post Simple maths can boost your app performance did some more thoughts over it in this post .Net compiler says no!! An attribute argument must be a constant expression, typeof expression or array creation expression of an attribute parameter type public class CustomAttribute : Attribute { public CriteriaOperator CriteriaOperator { get ; set ; } public CustomAttribute( CriteriaOperator criteriaOperator) { CriteriaOperator = criteriaOperator; } } [ CustomAttribute ( CriteriaOperator .Parse( "Name=?" , "eXpand" ))] public class Class1 { } the above cannot be compiled BUT XAF SAYS YES Why? Διαβάστε περισσότερα »...
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Sad but true... This article might read a bit cruel, but being a Greek I was astonished by how accurately it describes the sick situation in Greece, a situation which made me in 2009 try my luck some place else.... Διαβάστε περισσότερα »...
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Ο SQL Server 2008 R2, όπως και οι προηγούμενες εκδόσεις, είναι διαθέσιμος σε 32Bit και 64bit έκδοση. Υπάρχουν δύο τύποι αναβάθμισης που μπορείτε να κάνετε είτε από τον wizard από το CD εγκατάστασης είτε από command prompt αν σας αρέσει να παιδεύεστε :) 1ος: “In-place upgrade” Όπως μαρτυράει και το όνομα, αντικαθιστά το υπάρχον SQL Server instance μαζί με όλα τα data με τις νέες εκδόσεις του SQL Server 2008 R2. Αυτό σημαίνει ότι δεν χρειάζεται να κάνετε κάποιο migrate των δεδομένων μετά την αναβάθμιση αλλά ένα backup πριν πάντα είναι εκ των ουκ άνευ :) Μπορείτε, όπως φαίνεται και από την εικόνα, να κάνετε αντικατάσταση ενός ήδη υπάρχον sql instance αρκεί να είναι από SQL Server 2000 και άνω. Αν έχετε παλαιότερη και θέλετε να κάνετε αναβάθμιση θα πρέπει πρώτα να Διαβάστε περισσότερα »...
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How do they all connect? Well it boils down to the following questions: If I am using Entity Framework in a Desktop application when should I open the Context and for how long should I keep it open? I have ComboBoxes that will be used to select values for the Reference Properties of my Entity Framework objects. How am I going to achieve this? Should I bind to Reference Properties or should I include the Foreign Keys in my model (option named “Include Foreign Key columns in the model”) and bind to Διαβάστε περισσότερα »...
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Do I really need to say that dealing with irrationality is an exercise in futility? No, I don't think so, but of course no one talker will admit himself as being irrational or holding irrational beliefs. It's always the other... Διαβάστε περισσότερα »...
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Some years ago (before Xaf was born) you have bought an ERP for your company and you are not satisfied with its Analysis,Reporting,PIvoting,Sceduling etv capabilities and you wish the creator of your ERP to have use Xaf instead. If you are looking for the most painful way to map your ERP database into a Xaf application expand framework has the solution for you its called WorldCreator SqlDBMapper module. That module can map any Sql server database into a Xaf application. Bellow I demo how you can use it. Create an empty eXpand solution or use an existing one and navigate to the persistent assembly listview create a new persistent assembly info object, for the sake of the demo i will map NorthWind database, Use the Tools/Map Database action to connect to a database Διαβάστε περισσότερα »...
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Εδώ και κάποιες μέρες προσπαθούσα να εντοπίσω σε έναν server σε μια από της OLTP βάσεις που έχουμε, για πιο λόγο υπάρχουν θέματα σχετικά με την ταχύτητα και την απόδοση του συστήματος (να πω βέβαια ότι ο προκάτοχος μου δεν ασχολείτο με τέτοια θέματα...), είπα λοιπόν να το δω εγώ αφου οι άνθρωποι εδώ δεν έχουν και την καλύτερη εμπειρία σε θέματα SQL. Ο κατασκευαστής του προγράμματος βέβαια έλεγε ότι δεν φταίει η βάση σε επίπεδο σχεδιασμού ούτε σε επίπεδο administration καθώς είχε Auto Create Statistics & Auto Update Statistics set to True, κάτι με το οποίο διαφωνώ κατά κανόνα, και ότι έτσι όλα είναι θα έπρεπε να είναι ΟΚ. Άρα μάλλον είναι θέμα system. O systemας μου εδώ έσκιζε τα πτυχία του (MCSE) ότι δεν είναι θέμα system. Μετά από αρκετό ψάξιμο τελικά αποφάσισα Διαβάστε περισσότερα »...
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Xaf provides methods in your controllers to enable you to customize the types that is using. I am speaking about the CustomizeTypesInfo method internal class MyClass : ViewController { public override void CustomizeTypesInfo(DevExpress.ExpressApp.DC. ITypesInfo typesInfo) { base .CustomizeTypesInfo(typesInfo); } } The thing is that using such decoupled approach can be very dangerous and resource consuming. Take the following example . Say you have 10 classes and you want to customize 2 of them . You also want to decouple the customization logic. Then you probably write one controller like internal class MyController1 : ViewController { public Διαβάστε περισσότερα »...
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Έχετε ποτέ αναρωτηθεί τι σημαίνουν όλα αυτά τα εικονίδια στο Execution Plan που παράγεται στο SQL Server Management Studio; Εδώ είναι η απάντηση... http://msdn.microsoft.com/en-us/library/ms175913.aspx Ελπίζω να μην τα έχετε όλα σε ένα query :) tnt V. Διαβάστε περισσότερα »...
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Συνεχίζοντας τις περιπέτειες μου στον χώρο του monadic memoization, αποφάσισα να εμπλουτίσω την προηγουμενη προσπάθειά μου με το Continuation Monad, έτσι ώστε να έχω tail calls και να αποφύγω "περίεργα" stack overflows. Η ιδέα είναι να συνδυάσω το State Monad με το Continuation Monad (StateT Monad Transformer) και ως "δια μαγείας" όλα να δουλέψουν. type StateContMonad<'s, 'a, 'r> = StateContMonad of ('s -> ('s -> 'a -> 'r) -> 'r) type StateContBuilder() = member self.Return value = StateContMonad (fun state k -> k state value) member self.Bind(StateContMonad contStateMonad, f) = StateContMonad (fun state k -> contStateMonad state (fun state' value -> let (StateContMonad contMonad') = f value in contMonad' state' k)) member self.Delay( f : unit -> StateContMonad<'s, 'a, 'r> ) = StateContMonad (fun state k -> let (StateContMonad contStateMonad) = f () in contStateMonad state k) let memo = new StateContBuilder() // val Y : (('a -> 'b) -> 'a -> 'b) -> 'a -> 'b...
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Introduction In this blog post, we are going to see the classic Frogger game ported to Windows Phone 7. The game was created by Ionian University professor K. Anagnostou and his students (you can read more on prof. Anagnostou’s blog post here ). He also gave me the kind permission to port his source code from PC to Windows Phone 7, and he also suggested that I could use an accelerometer Διαβάστε περισσότερα »...
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Some of my colleagues are often reluctant to use ASP.NET 2.0 profile provider to store profile data for their web applications. The main reason for this is the fact that the default SqlProfileProvider that ships with ASP.NET 2.0 “blobicizes” Profile data using string, XML or binary serialization prior to storing information in SQL Server. This obviously puts a rather large overhead Διαβάστε περισσότερα »...
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Introduction The Windows Phone 7 emulator that gets installed when you download and install the developer tools does not have any way to access an accelerometer. Although you can add a reference to Microsoft.Devices.Sensors, you will not get any values during application execution. Since I have a Freescale badge that comes with an accelerometer sensor (among others) that works with Διαβάστε περισσότερα »...
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eXpand have AdditionalViewControlsProvider module that has been design to allow you to add custom controls on a predefined position (Bottom,Top) using its logic architecture ruling system We wanted to add some power to it so in eXpand v10 one is able to position its custom controls any where in the view by setting the rule position to DetailViewItem Then use the Model editor to create an additionalviewcontrol detailview item Associate them with a rule like and finally use the Layout Designer to place them at any position in the View!!! so when you go to the specified view since your rules can be activated uppon any logic your controls visibility will be setup accordingly Διαβάστε περισσότερα »...
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