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Πρόσφατες Δημοσιεύσεις
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Installing Roslyn on a machine where I had local administrator rights worked without issues. At work though, the installer crashed and the following event was logged: Fault bucket , type 0 Event Name: CLR20r3 Response: Not available Cab Id: 0 Problem signature: P1: vsixinstaller.exe P2: 12.0.30324.0 P3: 532f5607 P4: System P5: 4.0.30319.18408 P6: 52311185 P7: 1cf7 P8: 75 P9: System.UriFormatException P10: To overcome this, open a Development command prompt with administrator priviledges, go to the folder where Roslyn is stored and execute: vsixinstaller "Roslyn End User Preview.vsix"...
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at System.IO.Path.GetInvalidPathChars one reads: The array returned from this method is not guaranteed to contain the complete set of characters that are invalid in file and directory names note: can also call this method from non-trusted Silverlight app – not as Intellisense tooltip wrongly says in Visual Studio 2013 with Silverlight 5.1 I just found […]...
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I was recently adding drop-files support to ClipFlair Studio, so I had to do some research on the related API that is available to Silverlight apps. Silverlight supports a limited set of Drag-and-Drop interaction with the operating system (supposedly for security reasons, but most probably because of the classic cross-platform implementation pains). For example it […]...
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With Global Windows Azure Bootcamp only a few days away I just received confirmation of Read more...
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Πριν μερικές μέρες έγραψα το πρώτο μέρος για το συγκεκριμένο θέμα στο οποίο έδειξα όλη την περιπτωσιολογία πάνω σε αυτό. Σήμερα θα σας εξηγήσω όσο απλούστερα γίνεται τι κρύβεται πίσω από την κουρτίνα. http://www.sqlschool.gr/blog/understanding-index-external-fragmentation-part-ii-the-explanation-967.aspx...
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In a previous article we had some talk concerning AJAX. We used AJAX to read some simple file. Even though this may have seemed to be quite nice it is but a simple example of what AJAX can do. Things are going to get more interesting in this article where we will be talking about AJAX requests. In other words, how to exchange data between an html page and a server page depending on the requests parameters. GET and POST HTTP Request Methods, describe what the request is about to do. If this isn't the first time you are dealing with the web, you might have probably heard of the two most common methods, GET and POST. Let's try to describe what these terms actually mean. To begin with, both requests contain information. For example whether we ask for the second page inside a forum or fill out and send a form in a contact page, we send information to the server. However you may be able to tell the difference between these requests. In the first example we are asking the server for...
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Είμαι σίγουρος ότι έχετε ακούσει ουκ ολίγες φορές ότι μια από τις αιτίες που μπορεί να μειώνει την απόδοση των queries μας σε μια database είναι το index fragmentation (εφόσον βέβαια έχουμε σωστούς indexes και σωστά στατιστικά για αυτούς και φυσικά έχουμε γράψει queries που έχουν where clause) και ότι τo χειρότερο είναι το external fragmentation. http://www.sqlschool.gr/blog/understanding-index-external-fragmentation-part-i-the-cases-965.aspx...
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It seems that CaptureMouse is behaving differently in WPF and Silverlight, in that in the former one it immediately calls OnLostMouseCapture at a Visual, whereas in Silverlight it doesn’t get called if the element didn’t have the mouse capture already (btw, in Silverlight that method is at a UIElement – there is no Visual ancestor […]...
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Introduction Every variable created in a .Net application can be either of value or reference type. C#'s value type consist of most basic types such as all numeric types, bools, enums and structs. All other types, such as strings, classes, interfaces etc, are reference types. At first you may guess that value types are simpler than reference types. A class for example can be much more complex than an integer. You may be right. However the actual reason we use this division, is the way such value types are copied, as well as the way they are stored in memory. Let's take a look at the memory part first. Memory allocation Supposing we declare an integer. int ValueTypeInteger = 0; What would we need to store its value? Just a single slot in memory where we will store 0 (and the variable's name). Now what if we had a class like this? class ReferenceTypeClass //Random class containing integer value { int _ReferenceTypeClass_Int;...
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copying from an e-mail I received from Skype support: Taking a screenshot on Windows desktop 1. On your keyboard, press the Print Screen (Prt Scr) key to take a screenshot of your entire desktop. To take a screenshot of an active window, press the Alt+Print Screen (Prt Scr) key combination. 2. Save a copy of […]...
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Testing is a part of every developers life. No matter how experienced a programmer you are, there are always times when, out of pressure or by mistake, something will go wrong. Sooner or later you will have to test your code to ensure that everything works according to plan. So, how can unit testing make our lives easier? Unit Testing is a tool that allows developers to easily test their source code and ensure that it works just fine, as if they had actually tested it. We are going to take a look at how it works, all the way from the beginning till you can create simple, yet effective, unit tests on your own. Getting started When testing, we compare the output of our project to what we are actually expecting to see. Supposing we create an application that sums up values. A simple test would be to try it out on two random numbers, 1 and 2. If the output is 3, our test was successful. However, the fact that we successfully got a 3, cannot ensure that by the time the projects is released,...
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Αυτή είναι μια από τις δημοφιλέστερες ερωτήσεις σχετικά με τον SQL Server. Ποιά είναι όμως η απάντησή της; http://www.sqlschool.gr/blog/what-is-the-proper-max-server-memory-setting-for-a-sql-server-with-n-gigabytes-of-installed-ram-963.aspx...
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Όλοι κάποια στιγμή έχουμε φτιάξει μια database είτε με το γραφικό περιβάλλον είτε με DDL statement (CREATE DATABASE). Για αυτούς που είναι λάτρεις του κώδικα και φτιάχνουν μια database με script υπάρχουν κάποια κρυφά μυστικά που είναι καλό να γνωρίζουν ;-) http://www.sqlschool.gr/blog/create-database-secrets-962.aspx...
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I have already written some articles concerning AJAX, now it's time to take another step and introduce JSON. Actually JSON is just a format - a standard - not a technique. However it is widely used in combination with AJAX in order to create asynchronous requests resulting in JSON data. What is JSON? JSON is a data format, nothing more nothing less. The same way we open a jpeg file and expect it to contain jpeg data, JSON data contains data in predefined form. The simplest example of that form would be { "ID" : 1 } Now, JSON is a format used to carry data, the same way XML does but in a more easy-to-read way to a human. Compare the XML with its JSON equivalent. < ID > 1 </ ID > { "ID" : 1 } JSON seems to be like reading a book in comparison to XML. JSON stands for JavaScript Object Notation. As you will see its contains use the form of an object. JSON was at first created for JavaScript, that's the reason this language is mentioned on its name. However,...
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Asynchronous programming has been a part of Microsoft's applications for a long time. However things tend to mature. .NET 4.5, released in August 2012, brought up C# 5 and VB 2012. And along came a new way of creating asynchronous methods. Instead of using multithreading or similar techniques, we now have access to an easier way using the key words async and await. Since a reader asked me, I am going to take a look at how these things work in today's article. What is asynchronous programming? The common way source code is handled, is synchronous (linear). That means that in order to accomplish two or more processes, that have nothing to do with each other (in other words, the sequence of these processes does not affect the result we get) we would have to wait for them all to complete one by one. Now, if the first process needed 10 seconds to complete and the second 5 seconds, the amount of time we would need to get the job done would be a total of 15 seconds. This way is no good because the second...
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Πριν από πολλά χρόνια είχα γράψει ένα σχετικό post με μια stored procedure. Με τα χρόνια αυτό άλλαζε καθώς οι ανάγκες και οι δυνατότητες άλλαζαν. Απλά σήμερα έτυχε να το χρησιμοποιήσω πάλι και λέω δε το μοιράζομαι με τον κόσμο όλο και κάποιος θα το χρειαστεί http://www.sqlschool.gr/blog/how-to-find-cpu-expensive-queries-961.aspx...
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Registrations for the Global Windows Azure bootcamp in Athens are now open. Now is the Read more...
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Ένα ερώτημα που όλους κάποια στιγμή έχει απασχολήσει και έχει δημιουργήσει ενδιαφέρουσες συζητήσεις είναι το που είναι καλύτερο να βάλω τα φίλτρα μου σε ένα join query, να τα βάλω στο where όπως θα έκανα ή να τα βάλω στο join; http://www.sqlschool.gr/blog/filtering-data-on-joins-or-to-where-clause-960.aspx...
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I was looking into some third-party code, upgrading it from Silverlight 4.x and was getting error ‘The member "Content" is not recognized or is not accessible’ at the following code part: Looking it up, found that you don’t need to bind the Content property of a ContentPresenter at all if you put it inside the […]...
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When was the last time you heard a website was hacked? Well, probably what you have heard of concerned some major properly secure website and the people who got access to it were no rookies. However this is no excuse for you to stand there waiting for a novice hacker to play around with your website. Let's go through a few of the most common and easy to handle techniques. Getting Started Web is a complicated thing. There are a lot of ways a malicious user may attack you. Just because between you and him lies the web. A user can create false responses, create false cookies or try to get access to your database. To begin with let's keep in mind that what we will be talking about is not the security of your web server. This is a whole new topic responsible of which is your host and not you. However you are responsible for what you have created. No host will be sorry you for your deleted database tables if you were not careful enough with your code. What's the whole idea of the attack? A nice way...
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Here are some DeepZoom image samples to enjoy via ClipFlair‘s Image component, in our ClipFlair Studio app (Silverlight-based): http://studio.clipflair.net/?image=http://static.seadragon.com/content/misc/blue-marble.dzi http://studio.clipflair.net/?image=http://static.seadragon.com/content/misc/earths-city-lights.dzi http://studio.clipflair.net/?image=http://static.seadragon.com/content/misc/carina-nebula.dzi http://studio.clipflair.net/?image=http://static.seadragon.com/content/misc/orion-nebula.dzi http://studio.clipflair.net/?image=http://static.seadragon.com/content/misc/contoso-fixster.dzi http://studio.clipflair.net/?image=http://static.seadragon.com/content/misc/milwaukee.dzi (hand-drawn pano, 1898) http://studio.clipflair.net/?image=http://static.seadragon.com/content/misc/last-fm.dzi http://studio.clipflair.net/?image=http://static.seadragon.com/content/misc/yosemite-panorama.dzi (try zooming onto the waterfall) http://studio.clipflair.net/?image=http://static.seadragon.com/content/misc/angkor-wat.dzi...
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In this article we are going to talk about abstract classes and interfaces. Both abstract classes and interfaces are a part of .Net's architecture and are not explicit of its web equivalent. They are a way of describing some characteristics a class may have in a way resembling the inheritance model. Yet, though these two may look similar there are a few significant differences and these will consist of the second part of the article. First there was inheritance I guess most developers know what inheritance is. Since a base class and an interface have much in common we'll go through the inheritance to reach the interface. In a few words inheritance is the connection between two classes when one of them gets the other one's characteristics. For example we can use the classes Parent and child. public class Parent { public string Name { get ; set ; } public void SetName() { Name =...
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Σαν DBA καθημερινά ερχόμαστε αντιμέτωποι με κάποιες περιπτώσεις δεν είναι εύκολο άμεσα να εντοπιστούν τα αίτια που τις δημιούργησαν. Εδώ έρχεται αυτό που χρόνια λέω και γράφω ότι πρέπει να γνωρίζουμε τα εσωτερικά του εργαλείου. Πρόσφατα δέχθηκα μια ερώτηση από έναν συνάδελφο που απετέλεσε το ερέθισμα για το post αυτό. http://www.sqlschool.gr/blog/update-statistics-and-trace-flag-2371-958.aspx...
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Τα τελευταία χρόνια έχει μεγάλη κουβέντα και μεγάλη χρήση από αρκετούς στην χρήση ORMs. Υπάρχουν αρκετά πλέον στην αγορά (EF, ΝHibernate κ.α.) και έτσι ο καθένας μπορεί να επιλέξει αυτό που του ταιριάζει. Αρκετές φορές έχω βρεθεί σε συζητήσεις σχετικά με αυτά και από αυτές έχω αποκτήσει την φήμη ότι είμαι από αυτούς που τα κατακρίνουν και στέκονται απέναντι τους. http://www.sqlschool.gr/blog/do-you-use-an-orm-please-learn-how-to-use-it-properly-957.aspx...
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Ένα ερώτημα που μου έχει τεθεί τόσες φορές που έχω χάσει πλέον τον αριθμό. Αλήθεια υπάρχει απάντηση σε αυτό; http://www.sqlschool.gr/blog/the-answer-on-question-which-is-the-best-database-is-it-depends-956.aspx...
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