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• Java Logger API

  - by Koppar

  This is a more like a tip rather than technical write up and serves as a quick intro for newbies. The logger API helps to diagnose application level or JDK level issues at runtime. There are 7 levels which decide the detailing in logging (SEVERE, WARNING, INFO, CONFIG, FINE, FINER, FINEST). Its best to start with highest level and as we narrow down, use more detailed logging for a specific area. SEVERE is the highest and FINEST is the lowest. This may not make sense until we understand some jargon. The Logger class provides the ability to stream messages to an output stream in a format that can be controlled by the user. What this translates to is, I can create a logger with this simple invocation and use it add debug messages in my class: import java.util.logging.*; private static final Logger focusLog = Logger.getLogger("java.awt.focus.KeyboardFocusManager"); if (focusLog.isLoggable(Level.FINEST)) { focusLog.log(Level.FINEST, "Calling peer setCurrentFocusOwner}); LogManager acts like a book keeper and all the getLogger calls are forwarded to LogManager. The LogManager itself is a singleton class object which gets statically initialized on JVM start up. More on this later. If there is no existing logger with the given name, a new one is created. If there is one (and not yet GC’ed), then the existing Logger object is returned. By default, a root logger is created on JVM start up. All anonymous loggers are made as the children of the root logger. Named loggers have the hierarchy as per their name resolutions. Eg: java.awt.focus is the parent logger for java.awt.focus.KeyboardFocusManager etc. Before logging any message, the logger checks for the log level specified. If null is specified, the log level of the parent logger will be set. However, if the log level is off, no log messages would be written, irrespective of the parent’s log level. All the messages that are posted to the Logger are handled as a LogRecord object.i.e. FocusLog.log would create a new LogRecord object with the log level and message as its data members). The level of logging and thread number are also tracked. LogRecord is passed on to all the registered Handlers. Handler is basically a means to output the messages. The output may be redirected to either a log file or console or a network logging service. The Handler classes use the LogManager properties to set filters and formatters. During initialization or JVM start up, LogManager looks for logging.properties file in jre/lib and sets the properties if the file is provided. An alternate location for properties file can also be specified by setting java.util.logging.config.file system property. This can be set in Java Control Panel ? Java ? Runtime parameters as -Djava.util.logging.config.file = <mylogfile> or passed as a command line parameter java -Djava.util.logging.config.file = C:/Sunita/myLog The redirection of logging depends on what is specified rather registered as a handler with JVM in the properties file. java.util.logging.ConsoleHandler sends the output to system.err and java.util.logging.FileHandler sends the output to file. File name of the log file can also be specified. If you prefer XML format output, in the configuration file, set java.util.logging.FileHandler.formatter = java.util.logging.XMLFormatter and if you prefer simple text, set set java.util.logging.FileHandler.formatter =java.util.logging.SimpleFormatter Below is the default logging Configuration file: ############################################################ # Default Logging Configuration File # You can use a different file by specifying a filename # with the java.util.logging.config.file system property. # For example java -Djava.util.logging.config.file=myfile ############################################################ ############################################################ # Global properties ############################################################ # "handlers" specifies a comma separated list of log Handler # classes. These handlers will be installed during VM startup. # Note that these classes must be on the system classpath. # By default we only configure a ConsoleHandler, which will only # show messages at the INFO and above levels. handlers= java.util.logging.ConsoleHandler # To also add the FileHandler, use the following line instead. #handlers= java.util.logging.FileHandler, java.util.logging.ConsoleHandler # Default global logging level. # This specifies which kinds of events are logged across # all loggers. For any given facility this global level # can be overriden by a facility specific level # Note that the ConsoleHandler also has a separate level # setting to limit messages printed to the console. .level= INFO ############################################################ # Handler specific properties. # Describes specific configuration info for Handlers. ############################################################ # default file output is in user's home directory. java.util.logging.FileHandler.pattern = %h/java%u.log java.util.logging.FileHandler.limit = 50000 java.util.logging.FileHandler.count = 1 java.util.logging.FileHandler.formatter = java.util.logging.XMLFormatter # Limit the message that are printed on the console to INFO and above. java.util.logging.ConsoleHandler.level = INFO java.util.logging.ConsoleHandler.formatter = java.util.logging.SimpleFormatter ############################################################ # Facility specific properties. # Provides extra control for each logger. ############################################################ # For example, set the com.xyz.foo logger to only log SEVERE # messages: com.xyz.foo.level = SEVERE Since I primarily use this method to track focus issues, here is how I get detailed awt focus related logging. Just set the logger name to java.awt.focus.level=FINEST and change the default log level to FINEST. Below is a basic sample program. The sample programs are from http://www2.cs.uic.edu/~sloan/CLASSES/java/ and have been modified to illustrate the logging API. By changing the .level property in the logging.properties file, one can control the output written to the logs. To play around with the example, try changing the levels in the logging.properties file and notice the difference in messages going to the log file. Example --------KeyboardReader.java------------------------------------------------------------------------------------- import java.io.*; import java.util.*; import java.util.logging.*; public class KeyboardReader { private static final Logger mylog = Logger.getLogger("samples.input"); public static void main (String[] args) throws java.io.IOException { String s1; String s2; double num1, num2, product; // set up the buffered reader to read from the keyboard BufferedReader br = new BufferedReader (new InputStreamReader (System.in)); System.out.println ("Enter a line of input"); s1 = br.readLine(); if (mylog.isLoggable(Level.SEVERE)) { mylog.log (Level.SEVERE,"The line entered is " + s1); } if (mylog.isLoggable(Level.INFO)) { mylog.log (Level.INFO,"The line has " + s1.length() + " characters"); } if (mylog.isLoggable(Level.FINE)) { mylog.log (Level.FINE,"Breaking the line into tokens we get:"); } int numTokens = 0; StringTokenizer st = new StringTokenizer (s1); while (st.hasMoreTokens()) { s2 = st.nextToken(); numTokens++; if (mylog.isLoggable(Level.FINEST)) { mylog.log (Level.FINEST, " Token " + numTokens + " is: " + s2); } } } } ----------MyFileReader.java---------------------------------------------------------------------------------------- import java.io.*; import java.util.*; import java.util.logging.*; public class MyFileReader extends KeyboardReader { private static final Logger mylog = Logger.getLogger("samples.input.file"); public static void main (String[] args) throws java.io.IOException { String s1; String s2; // set up the buffered reader to read from the keyboard BufferedReader br = new BufferedReader (new FileReader ("MyFileReader.txt")); s1 = br.readLine(); if (mylog.isLoggable(Level.SEVERE)) { mylog.log (Level.SEVERE,"ATTN The line is " + s1); } if (mylog.isLoggable(Level.INFO)) { mylog.log (Level.INFO, "The line has " + s1.length() + " characters"); } if (mylog.isLoggable(Level.FINE)) { mylog.log (Level.FINE,"Breaking the line into tokens we get:"); } int numTokens = 0; StringTokenizer st = new StringTokenizer (s1); while (st.hasMoreTokens()) { s2 = st.nextToken(); numTokens++; if (mylog.isLoggable(Level.FINEST)) { mylog.log (Level.FINEST,"Breaking the line into tokens we get:"); mylog.log (Level.FINEST," Token " + numTokens + " is: " + s2); } } //end of while } // end of main } // end of class ----------MyFileReader.txt------------------------------------------------------------------------------------------ My first logging example -------logging.properties------------------------------------------------------------------------------------------- handlers= java.util.logging.ConsoleHandler, java.util.logging.FileHandler .level= FINEST java.util.logging.FileHandler.pattern = java%u.log java.util.logging.FileHandler.limit = 50000 java.util.logging.FileHandler.count = 1 java.util.logging.FileHandler.formatter = java.util.logging.SimpleFormatter java.util.logging.ConsoleHandler.level = FINEST java.util.logging.ConsoleHandler.formatter = java.util.logging.SimpleFormatter java.awt.focus.level=ALL ------Output log------------------------------------------------------------------------------------------- May 21, 2012 11:44:55 AM MyFileReader main SEVERE: ATTN The line is My first logging example May 21, 2012 11:44:55 AM MyFileReader main INFO: The line has 24 characters May 21, 2012 11:44:55 AM MyFileReader main FINE: Breaking the line into tokens we get: May 21, 2012 11:44:55 AM MyFileReader main FINEST: Breaking the line into tokens we get: May 21, 2012 11:44:55 AM MyFileReader main FINEST: Token 1 is: My May 21, 2012 11:44:55 AM MyFileReader main FINEST: Breaking the line into tokens we get: May 21, 2012 11:44:55 AM MyFileReader main FINEST: Token 2 is: first May 21, 2012 11:44:55 AM MyFileReader main FINEST: Breaking the line into tokens we get: May 21, 2012 11:44:55 AM MyFileReader main FINEST: Token 3 is: logging May 21, 2012 11:44:55 AM MyFileReader main FINEST: Breaking the line into tokens we get: May 21, 2012 11:44:55 AM MyFileReader main FINEST: Token 4 is: example Invocation command: "C:\Program Files (x86)\Java\jdk1.6.0_29\bin\java.exe" -Djava.util.logging.config.file=logging.properties MyFileReader References Further technical details are available here: http://docs.oracle.com/javase/1.4.2/docs/guide/util/logging/overview.html#1.0 http://docs.oracle.com/javase/1.4.2/docs/api/java/util/logging/package-summary.html http://www2.cs.uic.edu/~sloan/CLASSES/java/

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• WPF ListView as a DataGrid – Part 2

  - by psheriff

  In my last blog post I showed you how to create GridViewColumn objects on the fly from the meta-data in a DataTable. By doing this you can create columns for a ListView at runtime instead of having to pre-define each ListView for each different DataTable. Well, many of us use collections of our classes and it would be nice to be able to do the same thing for our collection classes as well. This blog post will show you one approach for using collection classes as the source of the data for your ListView.  Figure 1: A List of Data using a ListView Load Property NamesYou could use reflection to gather the property names in your class, however there are two things wrong with this approach. First, reflection is too slow, and second you may not want to display all your properties from your class in the ListView. Instead of reflection you could just create your own custom collection class of PropertyHeader objects. Each PropertyHeader object will contain a property name and a header text value at a minimum. You could add a width property if you wanted as well. All you need to do is to create a collection of property header objects where each object represents one column in your ListView. Below is a simple example: PropertyHeaders coll = new PropertyHeaders(); coll.Add(new PropertyHeader("ProductId", "Product ID"));coll.Add(new PropertyHeader("ProductName", "Product Name"));coll.Add(new PropertyHeader("Price", "Price")); Once you have this collection created, you could pass this collection to a method that would create the GridViewColumn objects based on the information in this collection. Below is the full code for the PropertyHeader class. Besides the PropertyName and Header properties, there is a constructor that will allow you to set both properties when the object is created. C#public class PropertyHeader{  public PropertyHeader()  {  }   public PropertyHeader(string propertyName, string headerText)  {    PropertyName = propertyName;    HeaderText = headerText;  }   public string PropertyName { get; set; }  public string HeaderText { get; set; }} VB.NETPublic Class PropertyHeader  Public Sub New()  End Sub   Public Sub New(ByVal propName As String, ByVal header As String)    PropertyName = propName    HeaderText = header  End Sub   Private mPropertyName As String  Private mHeaderText As String   Public Property PropertyName() As String    Get      Return mPropertyName    End Get    Set(ByVal value As String)      mPropertyName = value    End Set  End Property   Public Property HeaderText() As String    Get      Return mHeaderText    End Get    Set(ByVal value As String)      mHeaderText = value    End Set  End PropertyEnd Class You can use a Generic List class to create a collection of PropertyHeader objects as shown in the following code. C#public class PropertyHeaders : List<PropertyHeader>{} VB.NETPublic Class PropertyHeaders  Inherits List(Of PropertyHeader)End Class Create Property Header Objects You need to create a method somewhere that will create and return a collection of PropertyHeader objects that will represent the columns you wish to add to your ListView prior to binding your collection class to that ListView. Below is a sample method called GetProperties that builds a list of PropertyHeader objects with properties and headers for a Product object. C#public PropertyHeaders GetProperties(){  PropertyHeaders coll = new PropertyHeaders();   coll.Add(new PropertyHeader("ProductId", "Product ID"));  coll.Add(new PropertyHeader("ProductName", "Product Name"));  coll.Add(new PropertyHeader("Price", "Price"));   return coll;} VB.NETPublic Function GetProperties() As PropertyHeaders  Dim coll As New PropertyHeaders()   coll.Add(New PropertyHeader("ProductId", "Product ID"))  coll.Add(New PropertyHeader("ProductName", "Product Name"))  coll.Add(New PropertyHeader("Price", "Price"))   Return collEnd Function WPFListViewCommon Class Now that you have a collection of PropertyHeader objects you need a method that will create a GridView and a collection of GridViewColumn objects based on this PropertyHeader collection. Below is a static/Shared method that you might put into a class called WPFListViewCommon. C#public static GridView CreateGridViewColumns(  PropertyHeaders properties){  GridView gv;  GridViewColumn gvc;   // Create the GridView  gv = new GridView();  gv.AllowsColumnReorder = true;   // Create the GridView Columns  foreach (PropertyHeader item in properties)  {    gvc = new GridViewColumn();    gvc.DisplayMemberBinding = new Binding(item.PropertyName);    gvc.Header = item.HeaderText;    gvc.Width = Double.NaN;    gv.Columns.Add(gvc);  }   return gv;} VB.NETPublic Shared Function CreateGridViewColumns( _    ByVal properties As PropertyHeaders) As GridView  Dim gv As GridView  Dim gvc As GridViewColumn   ' Create the GridView  gv = New GridView()  gv.AllowsColumnReorder = True   ' Create the GridView Columns  For Each item As PropertyHeader In properties    gvc = New GridViewColumn()    gvc.DisplayMemberBinding = New Binding(item.PropertyName)    gvc.Header = item.HeaderText    gvc.Width = [Double].NaN    gv.Columns.Add(gvc)  Next   Return gvEnd Function Build the Product Screen To build the window shown in Figure 1, you might write code like the following: C#private void CollectionSample(){  Product prod = new Product();   // Setup the GridView Columns  lstData.View = WPFListViewCommon.CreateGridViewColumns(       prod.GetProperties());  lstData.DataContext = prod.GetProducts();} VB.NETPrivate Sub CollectionSample()  Dim prod As New Product()   ' Setup the GridView Columns  lstData.View = WPFListViewCommon.CreateGridViewColumns( _       prod.GetProperties())  lstData.DataContext = prod.GetProducts()End Sub The Product class contains a method called GetProperties that returns a PropertyHeaders collection. You pass this collection to the WPFListViewCommon’s CreateGridViewColumns method and it will create a GridView for the ListView. When you then feed the DataContext property of the ListView the Product collection the appropriate columns have already been created and data bound. Summary In this blog you learned how to create a ListView that acts like a DataGrid using a collection class. While it does take a little code to do this, it is an alternative to creating each GridViewColumn in XAML. This gives you a lot of flexibility. You could even read in the property names and header text from an XML file for a truly configurable ListView. NOTE: You can download the complete sample code (in both VB and C#) at my website. http://www.pdsa.com/downloads. Choose Tips & Tricks, then "WPF ListView as a DataGrid – Part 2" from the drop-down. Good Luck with your Coding,Paul Sheriff ** SPECIAL OFFER FOR MY BLOG READERS **Visit http://www.pdsa.com/Event/Blog for a free eBook on "Fundamentals of N-Tier".  

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• Beware: Upgrade to ASP.NET MVC 2.0 with care if you use AntiForgeryToken

  - by James Crowley

  If you're thinking of upgrading to MVC 2.0, and you take advantage of the AntiForgeryToken support then be careful - you can easily kick out all active visitors after the upgrade until they restart their browser. Why's this?For the anti forgery validation to take place, ASP.NET MVC uses a session cookie called "__RequestVerificationToken_Lw__". This gets checked for and de-serialized on any page where there is an AntiForgeryToken() call. However, the format of this validation cookie has apparently changed between MVC 1.0 and MVC 2.0. What this means is that when you make to switch on your production server to MVC 2.0, suddenly all your visitors session cookies are invalid, resulting in calls to AntiForgeryToken() throwing exceptions (even on a standard GET request) when de-serializing it: [InvalidCastException: Unable to cast object of type 'System.Web.UI.Triplet' to type 'System.Object[]'.]   System.Web.Mvc.AntiForgeryDataSerializer.Deserialize(String serializedToken) +104[HttpAntiForgeryException (0x80004005): A required anti-forgery token was not supplied or was invalid.]   System.Web.Mvc.AntiForgeryDataSerializer.Deserialize(String serializedToken) +368   System.Web.Mvc.HtmlHelper.GetAntiForgeryTokenAndSetCookie(String salt, String domain, String path) +209   System.Web.Mvc.HtmlHelper.AntiForgeryToken(String salt, String domain, String path) +16   System.Web.Mvc.HtmlHelper.AntiForgeryToken() +10  <snip> So you've just kicked all your active users out of your site with exceptions until they think to restart their browser (to clear the session cookies). The only work around for now is to either write some code that wipes this cookie - or disable use of AntiForgeryToken() in your MVC 2.0 site until you're confident all session cookies will have expired. That in itself isn't very straightforward, given how frequently people tend to hibernate/standby their machines - the session cookie will only clear once the browser has been shut down and re-opened. Hope this helps someone out there!

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• First round playing with Memcached

  - by Shaun

  To be honest I have not been very interested in the caching before I’m going to a project which would be using the multi-site deployment and high connection and concurrency and very sensitive to the user experience. That means we must cache the output data for better performance. After looked for the Internet I finally focused on the Memcached. What’s the Memcached? I think the description on its main site gives us a very good and simple explanation. Free & open source, high-performance, distributed memory object caching system, generic in nature, but intended for use in speeding up dynamic web applications by alleviating database load. Memcached is an in-memory key-value store for small chunks of arbitrary data (strings, objects) from results of database calls, API calls, or page rendering. Memcached is simple yet powerful. Its simple design promotes quick deployment, ease of development, and solves many problems facing large data caches. Its API is available for most popular languages. The original Memcached was built on *nix system are is being widely used in the PHP world. Although it’s not a problem to use the Memcached installed on *nix system there are some windows version available fortunately. Since we are WISC (Windows – IIS – SQL Server – C#, which on the opposite of LAMP) it would be much easier for us to use the Memcached on Windows rather than *nix. I’m using the Memcached Win X64 version provided by NorthScale. There are also the x86 version and other operation system version.   Install Memcached Unpack the Memcached file to a folder on the machine you want it to be installed, we can see that there are only 3 files and the main file should be the “memcached.exe”. Memcached would be run on the server as a service. To install the service just open a command windows and navigate to the folder which contains the “memcached.exe”, let’s say “C:\Memcached\”, and then type “memcached.exe -d install”. If you are using Windows Vista and Windows 7 system please be execute the command through the administrator role. Right-click the command item in the start menu and use “Run as Administrator”, otherwise the Memcached would not be able to be installed successfully. Once installed successful we can type “memcached.exe -d start” to launch the service. Now it’s ready to be used. The default port of Memcached is 11211 but you can change it through the command argument. You can find the help by typing “memcached -h”.   Using Memcached Memcahed has many good and ready-to-use providers for vary program language. After compared and reviewed I chose the Memcached Providers. It’s built based on another 3rd party Memcached client named enyim.com Memcached Client. The Memcached Providers is very simple to set/get the cached objects through the Memcached servers and easy to be configured through the application configuration file (aka web.config and app.config). Let’s create a console application for the demonstration and add the 3 DLL files from the package of the Memcached Providers to the project reference. Then we need to add the configuration for the Memcached server. Create an App.config file and firstly add the section on top of it. Here we need three sections: the section for Memcached Providers, for enyim.com Memcached client and the log4net. 1: <configSections> 2: <section name="cacheProvider" 3: type="MemcachedProviders.Cache.CacheProviderSection, MemcachedProviders" 4: allowDefinition="MachineToApplication" 5: restartOnExternalChanges="true"/> 6: <sectionGroup name="enyim.com"> 7: <section name="memcached" 8: type="Enyim.Caching.Configuration.MemcachedClientSection, Enyim.Caching"/> 9: </sectionGroup> 10: <section name="log4net" 11: type="log4net.Config.Log4NetConfigurationSectionHandler,log4net"/> 12: </configSections> Then we will add the configuration for 3 of them in the App.config file. The Memcached server information would be defined under the enyim.com section since it will be responsible for connect to the Memcached server. Assuming I installed the Memcached on two servers with the default port, the configuration would be like this. 1: <enyim.com> 2: <memcached> 3: <servers> 4: <!-- put your own server(s) here--> 5: <add address="192.168.0.149" port="11211"/> 6: <add address="10.10.20.67" port="11211"/> 7: </servers> 8: <socketPool minPoolSize="10" maxPoolSize="100" connectionTimeout="00:00:10" deadTimeout="00:02:00"/> 9: </memcached> 10: </enyim.com> Memcached supports the multi-deployment which means you can install the Memcached on the servers as many as you need. The protocol of the Memcached responsible for routing the cached objects into the proper server. So it’s very easy to scale-out your system by Memcached. And then define the Memcached Providers configuration. The defaultExpireTime indicates how long the objected cached in the Memcached would be expired, the default value is 2000 ms. 1: <cacheProvider defaultProvider="MemcachedCacheProvider"> 2: <providers> 3: <add name="MemcachedCacheProvider" 4: type="MemcachedProviders.Cache.MemcachedCacheProvider, MemcachedProviders" 5: keySuffix="_MySuffix_" 6: defaultExpireTime="2000"/> 7: </providers> 8: </cacheProvider> The last configuration would be the log4net. 1: <log4net> 2: <!-- Define some output appenders --> 3: <appender name="ConsoleAppender" type="log4net.Appender.ConsoleAppender"> 4: <layout type="log4net.Layout.PatternLayout"> 5: <conversionPattern value="%date [%thread] %-5level %logger [%property{NDC}] - %message%newline"/> 6: </layout> 7: </appender> 8: <!--<threshold value="OFF" />--> 9: <!-- Setup the root category, add the appenders and set the default priority --> 10: <root> 11: <priority value="WARN"/> 12: <appender-ref ref="ConsoleAppender"> 13: <filter type="log4net.Filter.LevelRangeFilter"> 14: <levelMin value="WARN"/> 15: <levelMax value="FATAL"/> 16: </filter> 17: </appender-ref> 18: </root> 19: </log4net>   Get, Set and Remove the Cached Objects Once we finished the configuration it would be very simple to consume the Memcached servers. The Memcached Providers gives us a static class named DistCache that can be used to operate the Memcached servers. Get<T>: Retrieve the cached object from the Memcached servers. If failed it will return null or the default value. Add: Add an object with a unique key into the Memcached servers. Assuming that we have an operation that retrieve the email from the name which is time consuming. This is the operation that should be cached. The method would be like this. I utilized Thread.Sleep to simulate the long-time operation. 1: static string GetEmailByNameSlowly(string name) 2: { 3: Thread.Sleep(2000); 4: return name + "@ethos.com.cn"; 5: } Then in the real retrieving method we will firstly check whether the name, email information had been searched previously and cached. If yes we will just return them from the Memcached, otherwise we will invoke the slowly method to retrieve it and then cached. 1: static string GetEmailByName(string name) 2: { 3: var email = DistCache.Get<string>(name); 4: if (string.IsNullOrEmpty(email)) 5: { 6: Console.WriteLine("==> The name/email not be in memcached so need slow loading. (name = {0})==>", name); 7: email = GetEmailByNameSlowly(name); 8: DistCache.Add(name, email); 9: } 10: else 11: { 12: Console.WriteLine("==> The name/email had been in memcached. (name = {0})==>", name); 13: } 14: return email; 15: } Finally let’s finished the calling method and execute. 1: static void Main(string[] args) 2: { 3: var name = string.Empty; 4: while (name != "q") 5: { 6: Console.Write("==> Please enter the name to find the email: "); 7: name = Console.ReadLine(); 8:  9: var email = GetEmailByName(name); 10: Console.WriteLine("==> The email of {0} is {1}.", name, email); 11: } 12: } The first time I entered “ziyanxu” it takes about 2 seconds to get the email since there’s nothing cached. But the next time I entered “ziyanxu” it returned very quickly from the Memcached.   Summary In this post I explained a bit on why we need cache, what’s Memcached and how to use it through the C# application. The example is fairly simple but hopefully demonstrated on how to use it. Memcached is very easy and simple to be used since it gives you the full opportunity to consider what, when and how to cache the objects. And when using Memcached you don’t need to consider the cache servers. The Memcached would be like a huge object pool in front of you. The next step I’m thinking now are: What kind of data should be cached? And how to determined the key? How to implement the cache as a layer on top of the business layer so that the application will not notice that the cache is there. How to implement the cache by AOP so that the business logic no need to consider the cache. I will investigate on them in the future and will share my thoughts and results.   Hope this helps, Shaun All documents and related graphics, codes are provided "AS IS" without warranty of any kind. Copyright © Shaun Ziyan Xu. This work is licensed under the Creative Commons License.

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• Downloading a file over HTTP the SSIS way

  This post shows you how to download files from a web site whilst really making the most of the SSIS objects that are available. There is no task to do this, so we have to use the Script Task and some simple VB.NET or C# (if you have SQL Server 2008) code. Very often I see suggestions about how to use the .NET class System.Net.WebClient and of course this works, you can code pretty much anything you like in .NET. Here I’d just like to raise the profile of an alternative. This approach uses the HTTP Connection Manager, one of the stock connection managers, so you can use configurations and property expressions in the same way you would for all other connections. Settings like the security details that you would want to make configurable already are, but if you take the .NET route you have to write quite a lot of code to manage those values via package variables. Using the connection manager we get all of that flexibility for free. The screenshot below illustrate some of the options we have. Using the HttpClientConnection class makes for much simpler code as well. I have demonstrated two methods, DownloadFile which just downloads a file to disk, and DownloadData which downloads the file and retains it in memory. In each case we show a message box to note the completion of the download. You can download a sample package below, but first the code: Imports System Imports System.IO Imports System.Text Imports System.Windows.Forms Imports Microsoft.SqlServer.Dts.Runtime Public Class ScriptMain Public Sub Main() ' Get the unmanaged connection object, from the connection manager called "HTTP Connection Manager" Dim nativeObject As Object = Dts.Connections("HTTP Connection Manager").AcquireConnection(Nothing) ' Create a new HTTP client connection Dim connection As New HttpClientConnection(nativeObject) ' Download the file #1 ' Save the file from the connection manager to the local path specified Dim filename As String = "C:\Temp\Sample.txt" connection.DownloadFile(filename, True) ' Confirm file is there If File.Exists(filename) Then MessageBox.Show(String.Format("File {0} has been downloaded.", filename)) End If ' Download the file #2 ' Read the text file straight into memory Dim buffer As Byte() = connection.DownloadData() Dim data As String = Encoding.ASCII.GetString(buffer) ' Display the file contents MessageBox.Show(data) Dts.TaskResult = Dts.Results.Success End Sub End Class Sample Package HTTPDownload.dtsx (74KB)

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• Using Microsoft's Chart Controls In An ASP.NET Application: Serializing Chart Data

  In most usage scenarios, the data displayed in a Microsoft Chart control comes from some dynamic source, such as from a database query. The appearance of the chart can be modified dynamically, as well; past installments in this article series showed how to programmatically customize the axes, labels, and other appearance-related settings. However, it is possible to statically define the chart's data and appearance strictly through the control's declarative markup. One of the demos examined in the Getting Started article rendered a column chart with seven columns whose labels and values were defined statically in the <asp:Series> tag's <Points> collection. Given this functionality, it should come as no surprise that the Microsoft Chart Controls also support serialization. Serialization is the process of persisting the state of a control or an object to some other medium, such as to disk. Deserialization is the inverse process, and involves taking the persisted data and recreating the control or object. With just a few lines of code you can persist the appearance settings, the data, or both to a file on disk or to any stream. Likewise, it takes just a few lines of codes to reconstitute a chart from the persisted information. This article shows how to use the Microsoft Chart Control's serialization functionality by examining a demo application that allows users to create custom charts, specifying the data to plot and some appearance-related settings. The user can then save a "snapshot" of this chart, which persists its appearance and data to a record in a database. From another page, users can view these saved chart snapshots. Read on to learn more! Read More >

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• Exam 70-480 Study Material: Programming in HTML5 with JavaScript and CSS3

  - by Stacy Vicknair

  Here’s a list of sources of information for the different elements that comprise the 70-480 exam: General Resources http://www.w3schools.com (As pointed out in David Pallmann’s blog some of this content is unverified, but it is a decent source of information. For more about when it isn’t decent, see http://www.w3fools.com ) http://www.bloggedbychris.com/2012/09/19/microsoft-exam-70-480-study-guide/ (A guy who did a lot of what I did already, sadly I found this halfway through finishing my resources list. This list is expertly put together so I would recommend checking it out.) http://davidpallmann.blogspot.com/2012/08/microsoft-certification-exam-70-480.html http://pluralsight.com/training/Courses (Yes, this isn’t free, but if you look at the course listing there is an entire section on HTML5, CSS3 and Javascript. You can always try the trial!)   Some of the links I put below will overlap with the other resources above, but I tried to find explanations that looked beneficial to me on links outside those already mentioned.   Test Breakdown Implement and Manipulate Document Structures and Objects (24%) Create the document structure. o This objective may include but is not limited to: structure the UI by using semantic markup, including for search engines and screen readers (Section, Article, Nav, Header, Footer, and Aside); create a layout container in HTML http://www.w3schools.com/html/html5_new_elements.asp   Write code that interacts with UI controls. o This objective may include but is not limited to: programmatically add and modify HTML elements; implement media controls; implement HTML5 canvas and SVG graphics http://www.w3schools.com/html/html5_canvas.asp http://www.w3schools.com/html/html5_svg.asp   Apply styling to HTML elements programmatically. o This objective may include but is not limited to: change the location of an element; apply a transform; show and hide elements   Implement HTML5 APIs. o This objective may include but is not limited to: implement storage APIs, AppCache API, and Geolocation API http://www.w3schools.com/html/html5_geolocation.asp http://www.w3schools.com/html/html5_webstorage.asp http://www.w3schools.com/html/html5_app_cache.asp   Establish the scope of objects and variables. o This objective may include but is not limited to: define the lifetime of variables; keep objects out of the global namespace; use the “this” keyword to reference an object that fired an event; scope variables locally and globally http://robertnyman.com/2008/10/09/explaining-javascript-scope-and-closures/ http://www.quirksmode.org/js/this.html   Create and implement objects and methods. o This objective may include but is not limited to: implement native objects; create custom objects and custom properties for native objects using prototypes and functions; inherit from an object; implement native methods and create custom methods http://www.javascriptkit.com/javatutors/object.shtml http://www.crockford.com/javascript/inheritance.html http://stackoverflow.com/questions/1635116/javascript-class-method-vs-class-prototype-method http://www.javascriptkit.com/javatutors/proto.shtml     Implement Program Flow (25%) Implement program flow. o This objective may include but is not limited to: iterate across collections and array items; manage program decisions by using switch statements, if/then, and operators; evaluate expressions http://www.javascriptkit.com/jsref/looping.shtml http://www.javascriptkit.com/javatutors/varshort.shtml http://www.javascriptkit.com/javatutors/switch.shtml   Raise and handle an event. o This objective may include but is not limited to: handle common events exposed by DOM (OnBlur, OnFocus, OnClick); declare and handle bubbled events; handle an event by using an anonymous function http://dev.w3.org/2006/webapi/DOM-Level-3-Events/html/DOM3-Events.html http://javascript.info/tutorial/bubbling-and-capturing   Implement exception handling. o This objective may include but is not limited to: set and respond to error codes; throw an exception; request for null checks; implement try-catch-finally blocks http://www.javascriptkit.com/javatutors/trycatch.shtml   Implement a callback. o This objective may include but is not limited to: receive messages from the HTML5 WebSocket API; use jQuery to make an AJAX call; wire up an event; implement a callback by using anonymous functions; handle the “this” pointer http://www.w3.org/TR/2011/WD-websockets-20110419/ http://www.html5rocks.com/en/tutorials/websockets/basics/ http://api.jquery.com/jQuery.ajax/   Create a web worker process. o This objective may include but is not limited to: start and stop a web worker; pass data to a web worker; configure timeouts and intervals on the web worker; register an event listener for the web worker; limitations of a web worker https://developer.mozilla.org/en-US/docs/DOM/Using_web_workers http://www.html5rocks.com/en/tutorials/workers/basics/   Access and Secure Data (26%) Validate user input by using HTML5 elements. o This objective may include but is not limited to: choose the appropriate controls based on requirements; implement HTML input types and content attributes (for example, required) to collect user input http://diveintohtml5.info/forms.html   Validate user input by using JavaScript. o This objective may include but is not limited to: evaluate a regular expression to validate the input format; validate that you are getting the right kind of data type by using built-in functions; prevent code injection http://www.regular-expressions.info/javascript.html http://msdn.microsoft.com/en-us/library/66ztdbe6(v=vs.94).aspx https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Operators/typeof http://blog.stackoverflow.com/2008/06/safe-html-and-xss/ http://stackoverflow.com/questions/942011/how-to-prevent-javascript-injection-attacks-within-user-generated-html   Consume data. o This objective may include but is not limited to: consume JSON and XML data; retrieve data by using web services; load data or get data from other sources by using XMLHTTPRequest http://www.erichynds.com/jquery/working-with-xml-jquery-and-javascript/ http://www.webdevstuff.com/86/javascript-xmlhttprequest-object.html http://www.json.org/ http://stackoverflow.com/questions/4935632/how-to-parse-json-in-javascript   Serialize, deserialize, and transmit data. o This objective may include but is not limited to: binary data; text data (JSON, XML); implement the jQuery serialize method; Form.Submit; parse data; send data by using XMLHTTPRequest; sanitize input by using URI/form encoding http://api.jquery.com/serialize/ http://www.javascript-coder.com/javascript-form/javascript-form-submit.phtml http://stackoverflow.com/questions/327685/is-there-a-way-to-read-binary-data-into-javascript https://developer.mozilla.org/en-US/docs/JavaScript/Reference/Global_Objects/encodeURI     Use CSS3 in Applications (25%) Style HTML text properties. o This objective may include but is not limited to: apply styles to text appearance (color, bold, italics); apply styles to text font (WOFF and @font-face, size); apply styles to text alignment, spacing, and indentation; apply styles to text hyphenation; apply styles for a text drop shadow http://www.w3schools.com/css/css_text.asp http://www.w3schools.com/css/css_font.asp http://nicewebtype.com/notes/2009/10/30/how-to-use-css-font-face/ http://webdesign.about.com/od/beginningcss/p/aacss5text.htm http://www.w3.org/TR/css3-text/ http://www.css3.info/preview/box-shadow/   Style HTML box properties. o This objective may include but is not limited to: apply styles to alter appearance attributes (size, border and rounding border corners, outline, padding, margin); apply styles to alter graphic effects (transparency, opacity, background image, gradients, shadow, clipping); apply styles to establish and change an element’s position (static, relative, absolute, fixed) http://net.tutsplus.com/tutorials/html-css-techniques/10-css3-properties-you-need-to-be-familiar-with/ http://www.w3schools.com/css/css_image_transparency.asp http://www.w3schools.com/cssref/pr_background-image.asp http://ie.microsoft.com/testdrive/graphics/cssgradientbackgroundmaker/default.html http://www.w3.org/TR/CSS21/visufx.html http://www.barelyfitz.com/screencast/html-training/css/positioning/ http://davidwalsh.name/css-fixed-position   Create a flexible content layout. o This objective may include but is not limited to: implement a layout using a flexible box model; implement a layout using multi-column; implement a layout using position floating and exclusions; implement a layout using grid alignment; implement a layout using regions, grouping, and nesting http://www.html5rocks.com/en/tutorials/flexbox/quick/ http://www.css3.info/preview/multi-column-layout/ http://msdn.microsoft.com/en-us/library/ie/hh673558(v=vs.85).aspx http://dev.w3.org/csswg/css3-grid-layout/ http://dev.w3.org/csswg/css3-regions/   Create an animated and adaptive UI. o This objective may include but is not limited to: animate objects by applying CSS transitions; apply 3-D and 2-D transformations; adjust UI based on media queries (device adaptations for output formats, displays, and representations); hide or disable controls http://www.bloggedbychris.com/2012/09/19/microsoft-exam-70-480-study-guide/   Find elements by using CSS selectors and jQuery. o This objective may include but is not limited to: choose the correct selector to reference an element; define element, style, and attribute selectors; find elements by using pseudo-elements and pseudo-classes (for example, :before, :first-line, :first-letter, :target, :lang, :checked, :first-child) http://www.bloggedbychris.com/2012/09/19/microsoft-exam-70-480-study-guide/   Structure a CSS file by using CSS selectors. o This objective may include but is not limited to: reference elements correctly; implement inheritance; override inheritance by using !important; style an element based on pseudo-elements and pseudo-classes (for example, :before, :first-line, :first-letter, :target, :lang, :checked, :first-child) http://www.bloggedbychris.com/2012/09/19/microsoft-exam-70-480-study-guide/   Technorati Tags: 70-480,CSS3,HTML5,HTML,CSS,JavaScript,Certification

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• ASP.NET MVC Validation Complete

  - by Ricardo Peres

  OK, so let’s talk about validation. Most people are probably familiar with the out of the box validation attributes that MVC knows about, from the System.ComponentModel.DataAnnotations namespace, such as EnumDataTypeAttribute, RequiredAttribute, StringLengthAttribute, RangeAttribute, RegularExpressionAttribute and CompareAttribute from the System.Web.Mvc namespace. All of these validators inherit from ValidationAttribute and perform server as well as client-side validation. In order to use them, you must include the JavaScript files MicrosoftMvcValidation.js, jquery.validate.js or jquery.validate.unobtrusive.js, depending on whether you want to use Microsoft’s own library or jQuery. No significant difference exists, but jQuery is more extensible. You can also create your own attribute by inheriting from ValidationAttribute, but, if you want to have client-side behavior, you must also implement IClientValidatable (all of the out of the box validation attributes implement it) and supply your own JavaScript validation function that mimics its server-side counterpart. Of course, you must reference the JavaScript file where the declaration function is. Let’s see an example, validating even numbers. First, the validation attribute: 1: [Serializable] 2: [AttributeUsage(AttributeTargets.Property, AllowMultiple = false, Inherited = true)] 3: public class IsEvenAttribute : ValidationAttribute, IClientValidatable 4: { 5: protected override ValidationResult IsValid(Object value, ValidationContext validationContext) 6: { 7: Int32 v = Convert.ToInt32(value); 8:  9: if (v % 2 == 0) 10: { 11: return (ValidationResult.Success); 12: } 13: else 14: { 15: return (new ValidationResult("Value is not even")); 16: } 17: } 18:  19: #region IClientValidatable Members 20:  21: public IEnumerable<ModelClientValidationRule> GetClientValidationRules(ModelMetadata metadata, ControllerContext context) 22: { 23: yield return (new ModelClientValidationRule() { ValidationType = "iseven", ErrorMessage = "Value is not even" }); 24: } 25:  26: #endregion 27: } The iseven validation function is declared like this in JavaScript, using jQuery validation: 1: jQuery.validator.addMethod('iseven', function (value, element, params) 2: { 3: return (true); 4: return ((parseInt(value) % 2) == 0); 5: }); 6:  7: jQuery.validator.unobtrusive.adapters.add('iseven', [], function (options) 8: { 9: options.rules['iseven'] = options.params; 10: options.messages['iseven'] = options.message; 11: }); Do keep in mind that this is a simple example, for example, we are not using parameters, which may be required for some more advanced scenarios. As a side note, if you implement a custom validator that also requires a JavaScript function, you’ll probably want them together. One way to achieve this is by including the JavaScript file as an embedded resource on the same assembly where the custom attribute is declared. You do this by having its Build Action set as Embedded Resource inside Visual Studio: Then you have to declare an attribute at assembly level, perhaps in the AssemblyInfo.cs file: 1: [assembly: WebResource("SomeNamespace.IsEven.js", "text/javascript")] In your views, if you want to include a JavaScript file from an embedded resource you can use this code: 1: public static class UrlExtensions 2: { 3: private static readonly MethodInfo getResourceUrlMethod = typeof(AssemblyResourceLoader).GetMethod("GetWebResourceUrlInternal", BindingFlags.NonPublic | BindingFlags.Static); 4:  5: public static IHtmlString Resource<TType>(this UrlHelper url, String resourceName) 6: { 7: return (Resource(url, typeof(TType).Assembly.FullName, resourceName)); 8: } 9:  10: public static IHtmlString Resource(this UrlHelper url, String assemblyName, String resourceName) 11: { 12: String resourceUrl = getResourceUrlMethod.Invoke(null, new Object[] { Assembly.Load(assemblyName), resourceName, false, false, null }).ToString(); 13: return (new HtmlString(resourceUrl)); 14: } 15: } And on the view: 1: <script src="<%: this.Url.Resource("SomeAssembly", "SomeNamespace.IsEven.js") %>" type="text/javascript"></script> Then there’s the CustomValidationAttribute. It allows externalizing your validation logic to another class, so you have to tell which type and method to use. The method can be static as well as instance, if it is instance, the class cannot be abstract and must have a public parameterless constructor. It can be applied to a property as well as a class. It does not, however, support client-side validation. Let’s see an example declaration: 1: [CustomValidation(typeof(ProductValidator), "OnValidateName")] 2: public String Name 3: { 4: get; 5: set; 6: } The validation method needs this signature: 1: public static ValidationResult OnValidateName(String name) 2: { 3: if ((String.IsNullOrWhiteSpace(name) == false) && (name.Length <= 50)) 4: { 5: return (ValidationResult.Success); 6: } 7: else 8: { 9: return (new ValidationResult(String.Format("The name has an invalid value: {0}", name), new String[] { "Name" })); 10: } 11: } Note that it can be either static or instance and it must return a ValidationResult-derived class. ValidationResult.Success is null, so any non-null value is considered a validation error. The single method argument must match the property type to which the attribute is attached to or the class, in case it is applied to a class: 1: [CustomValidation(typeof(ProductValidator), "OnValidateProduct")] 2: public class Product 3: { 4: } The signature must thus be: 1: public static ValidationResult OnValidateProduct(Product product) 2: { 3: } Continuing with attribute-based validation, another possibility is RemoteAttribute. This allows specifying a controller and an action method just for performing the validation of a property or set of properties. This works in a client-side AJAX way and it can be very useful. Let’s see an example, starting with the attribute declaration and proceeding to the action method implementation: 1: [Remote("Validate", "Validation")] 2: public String Username 3: { 4: get; 5: set; 6: } The controller action method must contain an argument that can be bound to the property: 1: public ActionResult Validate(String username) 2: { 3: return (this.Json(true, JsonRequestBehavior.AllowGet)); 4: } If in your result JSON object you include a string instead of the true value, it will consider it as an error, and the validation will fail. This string will be displayed as the error message, if you have included it in your view. You can also use the remote validation approach for validating your entire entity, by including all of its properties as included fields in the attribute and having an action method that receives an entity instead of a single property: 1: [Remote("Validate", "Validation", AdditionalFields = "Price")] 2: public String Name 3: { 4: get; 5: set; 6: } 7:  8: public Decimal Price 9: { 10: get; 11: set; 12: } The action method will then be: 1: public ActionResult Validate(Product product) 2: { 3: return (this.Json("Product is not valid", JsonRequestBehavior.AllowGet)); 4: } Only the property to which the attribute is applied and the additional properties referenced by the AdditionalFields will be populated in the entity instance received by the validation method. The same rule previously stated applies, if you return anything other than true, it will be used as the validation error message for the entity. The remote validation is triggered automatically, but you can also call it explicitly. In the next example, I am causing the full entity validation, see the call to serialize(): 1: function validate() 2: { 3: var form = $('form'); 4: var data = form.serialize(); 5: var url = '<%: this.Url.Action("Validation", "Validate") %>'; 6:  7: var result = $.ajax 8: ( 9: { 10: type: 'POST', 11: url: url, 12: data: data, 13: async: false 14: } 15: ).responseText; 16:  17: if (result) 18: { 19: //error 20: } 21: } Finally, by implementing IValidatableObject, you can implement your validation logic on the object itself, that is, you make it self-validatable. This will only work server-side, that is, the ModelState.IsValid property will be set to false on the controller’s action method if the validation in unsuccessful. Let’s see how to implement it: 1: public class Product : IValidatableObject 2: { 3: public String Name 4: { 5: get; 6: set; 7: } 8:  9: public Decimal Price 10: { 11: get; 12: set; 13: } 14:  15: #region IValidatableObject Members 16: 17: public IEnumerable<ValidationResult> Validate(ValidationContext validationContext) 18: { 19: if ((String.IsNullOrWhiteSpace(this.Name) == true) || (this.Name.Length > 50)) 20: { 21: yield return (new ValidationResult(String.Format("The name has an invalid value: {0}", this.Name), new String[] { "Name" })); 22: } 23: 24: if ((this.Price <= 0) || (this.Price > 100)) 25: { 26: yield return (new ValidationResult(String.Format("The price has an invalid value: {0}", this.Price), new String[] { "Price" })); 27: } 28: } 29: 30: #endregion 31: } The errors returned will be matched against the model properties through the MemberNames property of the ValidationResult class and will be displayed in their proper labels, if present on the view. On the controller action method you can check for model validity by looking at ModelState.IsValid and you can get actual error messages and related properties by examining all of the entries in the ModelState dictionary: 1: Dictionary<String, String> errors = new Dictionary<String, String>(); 2:  3: foreach (KeyValuePair<String, ModelState> keyValue in this.ModelState) 4: { 5: String key = keyValue.Key; 6: ModelState modelState = keyValue.Value; 7:  8: foreach (ModelError error in modelState.Errors) 9: { 10: errors[key] = error.ErrorMessage; 11: } 12: } And these are the ways to perform date validation in ASP.NET MVC. Don’t forget to use them!

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• Time Warp

  - by Jesse

  It’s no secret that daylight savings time can wreak havoc on systems that rely heavily on dates. The system I work on is centered around recording dates and times, so naturally my co-workers and I have seen our fair share of date-related bugs. From time to time, however, we come across something that we haven’t seen before. A few weeks ago the following error message started showing up in our logs: “The supplied DateTime represents an invalid time. For example, when the clock is adjusted forward, any time in the period that is skipped is invalid.” This seemed very cryptic, especially since it was coming from areas of our application that are typically only concerned with capturing date-only (no explicit time component) from the user, like reports that take a “start date” and “end date” parameter. For these types of parameters we just leave off the time component when capturing the date values, so midnight is used as a “placeholder” time. How is midnight an “invalid time”? Globalization Is Hard Over the last couple of years our software has been rolled out to users in several countries outside of the United States, including Brazil. Brazil begins and ends daylight savings time at midnight on pre-determined days of the year. On October 16, 2011 at midnight many areas in Brazil began observing daylight savings time at which time their clocks were set forward one hour. This means that at the instant it became midnight on October 16, it actually became 1:00 AM, so any time between 12:00 AM and 12:59:59 AM never actually happened. Because we store all date values in the database in UTC, always adjust any “local” dates provided by a user to UTC before using them as filters in a query. The error we saw was thrown by .NET when trying to convert the Brazilian local time of 2011-10-16 12:00 AM to UTC since that local time never actually existed. We hadn’t experienced this same issue with any of our US customers because the daylight savings time changes in the US occur at 2:00 AM which doesn’t conflict with our “placeholder” time of midnight. Detecting Invalid Times In .NET you might use code similar to the following for converting a local time to UTC: var localDate = new DateTime(2011, 10, 16); //2011-10-16 @ midnight const string timeZoneId = "E. South America Standard Time"; //Windows system timezone Id for "Brasilia" timezone. var localTimeZone = TimeZoneInfo.FindSystemTimeZoneById(timeZoneId); var convertedDate = TimeZoneInfo.ConvertTimeToUtc(localDate, localTimeZone); The code above throws the “invalid time” exception referenced above. We could try to detect whether or not the local time is invalid with something like this: var localDate = new DateTime(2011, 10, 16); //2011-10-16 @ midnight const string timeZoneId = "E. South America Standard Time"; //Windows system timezone Id for "Brasilia" timezone. var localTimeZone = TimeZoneInfo.FindSystemTimeZoneById(timeZoneId); if (localTimeZone.IsInvalidTime(localDate)) localDate = localDate.AddHours(1); var convertedDate = TimeZoneInfo.ConvertTimeToUtc(localDate, localTimeZone); This code works in this particular scenario, but it hardly seems robust. It also does nothing to address the issue that can arise when dealing with the ambiguous times that fall around the end of daylight savings. When we roll the clocks back an hour they record the same hour on the same day twice in a row. To continue on with our Brazil example, on February 19, 2012 at 12:00 AM, it will immediately become February 18, 2012 at 11:00 PM all over again. In this scenario, how should we interpret February 18, 2011 11:30 PM? Enter Noda Time I heard about Noda Time, the .NET port of the Java library Joda Time, a little while back and filed it away in the back of my mind under the “sounds-like-it-might-be-useful-someday” category.  Let’s see how we might deal with the issue of invalid and ambiguous local times using Noda Time (note that as of this writing the samples below will only work using the latest code available from the Noda Time repo on Google Code. The NuGet package version 0.1.0 published 2011-08-19 will incorrectly report unambiguous times as being ambiguous) : var localDateTime = new LocalDateTime(2011, 10, 16, 0, 0); const string timeZoneId = "Brazil/East"; var timezone = DateTimeZone.ForId(timeZoneId); var localDateTimeMaping = timezone.MapLocalDateTime(localDateTime); ZonedDateTime unambiguousLocalDateTime; switch (localDateTimeMaping.Type) { case ZoneLocalMapping.ResultType.Unambiguous: unambiguousLocalDateTime = localDateTimeMaping.UnambiguousMapping; break; case ZoneLocalMapping.ResultType.Ambiguous: unambiguousLocalDateTime = localDateTimeMaping.EarlierMapping; break; case ZoneLocalMapping.ResultType.Skipped: unambiguousLocalDateTime = new ZonedDateTime( localDateTimeMaping.ZoneIntervalAfterTransition.Start, timezone); break; default: throw new InvalidOperationException(string.Format("Unexpected mapping result type: {0}", localDateTimeMaping.Type)); } var convertedDateTime = unambiguousLocalDateTime.ToInstant().ToDateTimeUtc(); Let’s break this sample down: I’m using the Noda Time ‘LocalDateTime’ object to represent the local date and time. I’ve provided the year, month, day, hour, and minute (zeros for the hour and minute here represent midnight). You can think of a ‘LocalDateTime’ as an “invalidated” date and time; there is no information available about the time zone that this date and time belong to, so Noda Time can’t make any guarantees about its ambiguity. The ‘timeZoneId’ in this sample is different than the ones above. In order to use the .NET TimeZoneInfo class we need to provide Windows time zone ids. Noda Time expects an Olson (tz / zoneinfo) time zone identifier and does not currently offer any means of mapping the Windows time zones to their Olson counterparts, though project owner Jon Skeet has said that some sort of mapping will be publicly accessible at some point in the future. I’m making use of the Noda Time ‘DateTimeZone.MapLocalDateTime’ method to disambiguate the original local date time value. This method returns an instance of the Noda Time object ‘ZoneLocalMapping’ containing information about the provided local date time maps to the provided time zone.  The disambiguated local date and time value will be stored in the ‘unambiguousLocalDateTime’ variable as an instance of the Noda Time ‘ZonedDateTime’ object. An instance of this object represents a completely unambiguous point in time and is comprised of a local date and time, a time zone, and an offset from UTC. Instances of ZonedDateTime can only be created from within the Noda Time assembly (the constructor is ‘internal’) to ensure to callers that each instance represents an unambiguous point in time. The value of the ‘unambiguousLocalDateTime’ might vary depending upon the ‘ResultType’ returned by the ‘MapLocalDateTime’ method. There are three possible outcomes: If the provided local date time is unambiguous in the provided time zone I can immediately set the ‘unambiguousLocalDateTime’ variable from the ‘Unambiguous Mapping’ property of the mapping returned by the ‘MapLocalDateTime’ method. If the provided local date time is ambiguous in the provided time zone (i.e. it falls in an hour that was repeated when moving clocks backward from Daylight Savings to Standard Time), I can use the ‘EarlierMapping’ property to get the earlier of the two possible local dates to define the unambiguous local date and time that I need. I could have also opted to use the ‘LaterMapping’ property in this case, or even returned an error and asked the user to specify the proper choice. The important thing to note here is that as the programmer I’ve been forced to deal with what appears to be an ambiguous date and time. If the provided local date time represents a skipped time (i.e. it falls in an hour that was skipped when moving clocks forward from Standard Time to Daylight Savings Time),  I have access to the time intervals that fell immediately before and immediately after the point in time that caused my date to be skipped. In this case I have opted to disambiguate my local date and time by moving it forward to the beginning of the interval immediately following the skipped period. Again, I could opt to use the end of the interval immediately preceding the skipped period, or raise an error depending on the needs of the application. The point of this code is to convert a local date and time to a UTC date and time for use in a SQL Server database, so the final ‘convertedDate’  variable (typed as a plain old .NET DateTime) has its value set from a Noda Time ‘Instant’. An 'Instant’ represents a number of ticks since 1970-01-01 at midnight (Unix epoch) and can easily be converted to a .NET DateTime in the UTC time zone using the ‘ToDateTimeUtc()’ method. This sample is admittedly contrived and could certainly use some refactoring, but I think it captures the general approach needed to take a local date and time and convert it to UTC with Noda Time. At first glance it might seem that Noda Time makes this “simple” code more complicated and verbose because it forces you to explicitly deal with the local date disambiguation, but I feel that the length and complexity of the Noda Time sample is proportionate to the complexity of the problem. Using TimeZoneInfo leaves you susceptible to overlooking ambiguous and skipped times that could result in run-time errors or (even worse) run-time data corruption in the form of a local date and time being adjusted to UTC incorrectly. I should point out that this research is my first look at Noda Time and I know that I’ve only scratched the surface of its full capabilities. I also think it’s safe to say that it’s still beta software for the time being so I’m not rushing out to use it production systems just yet, but I will definitely be tinkering with it more and keeping an eye on it as it progresses.

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• Exception Handling

  - by raghu.yadav

  Here is the few links on which andre had demonstrateddifferences-of-handling-jboexception-in handling-exceptions-in-oracle-ui-shell However in this post we can see how to display exception in popup being in the same page. I use similar usecase as andre however we'll not be using Exception Handling property from taskflow, instead we use popup and invoke the same programmatically. This is a dynamic region example where user can select jobs or locations links to edit the records of corresponding tables being in the same page and click commit to save changes. To generate exception we deliberately change commit to CommitAction in commit action binding code created in the bean (same as andre) and catch the exception and add brief description of exception into #{pageFlowScope.message}. Drop Popup component after Commit button and add dialog within in popup button, bind the popup component to backing bean and invoke the same in catch clause as shown below. public String Commit() { try{ BindingContainer bindings = getBindings(); OperationBinding operationBinding = bindings.getOperationBinding("CommitAction"); Object result = operationBinding.execute(); if (!operationBinding.getErrors().isEmpty()) { return null; } }catch (NullPointerException e) { setELValue("#{pageFlowScope.message}", "NullPointerException..."); e.printStackTrace(); String popupId = this.getPopup().getClientId(FacesContext.getCurrentInstance()); PatternsPublicUtil.invokePopup(popupId); } return null; } } private void setELValue(String el, String value) { FacesContext facesContext = FacesContext.getCurrentInstance(); ELContext elContext = facesContext.getELContext(); ExpressionFactory expressionFactory = facesContext.getApplication().getExpressionFactory(); ValueExpression valueExp = expressionFactory.createValueExpression(elContext, el, Object.class); valueExp.setValue(elContext, value); } .

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• What is Polymorphism?

  - by SAMIR BHOGAYTA

  * Polymorphism is one of the primary characteristics (concept) of object-oriented programming. * Poly means many and morph means form. Thus, polymorphism refers to being able to use many forms of a type without regard to the details. * Polymorphism is the characteristic of being able to assign a different meaning specifically, to allow an entity such as a variable, a function, or an object to have more than one form. * Polymorphism is the ability to process objects differently depending on their data types. * Polymorphism is the ability to redefine methods for derived classes. Types of Polymorphism * Compile time Polymorphism * Run time Polymorphism Compile time Polymorphism * Compile time Polymorphism also known as method overloading * Method overloading means having two or more methods with the same name but with different signatures Example of Compile time polymorphism public class Calculations { public int add(int x, int y) { return x+y; } public int add(int x, int y, int z) { return x+y+z; } } Run time Polymorphism * Run time Polymorphism also known as method overriding * Method overriding means having two or more methods with the same name , same signature but with different implementation Example of Run time Polymorphism class Circle { public int radius = 0; public double getArea() { return 3.14 * radius * radius } } class Sphere { public double getArea() { return 4 * 3.14 * radius * radius } }

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• Unity stuck in 2D mode, Nvidia Quadro graphics "unknown", Nvidia-Current active but not in use

  - by Jordan Lund

  I've seen this problem reported under several questions, but I haven't been able to resolve any of it so I thought I'd bring it all in under one umbrella. I started a new job and was given a Dell Precision M6400 laptop with Nvidia Quadro FX 2700M graphics card. It had a previous version of Ubuntu on it, but nobody had any passwords for it so I wiped the drive and did a fresh install of 11.10 from scratch. I didn't do any updates during installation, preferring to do them after boot. Updates ran fine and the system works... except Unity is in 2D mode. System Settings - Additional Drivers shows that Nvidia-Current is active but not in use. System Settings - System Info shows Graphics Driver Unknown, Experience Standard Nvidia X Server Settings is installed and working, re-writing the xorg.conf did nothing. /usr/lib/nux/unity_support_test -p OpenGL vendor string: NVIDIA Corporation OpenGL renderer string: Quadro FX 2700M/PCI/SSE2 OpenGL version string: 3.3.0 NVIDIA 285.05.09 Not software rendered: yes Not blacklisted: yes GLX fbconfig: yes GLX texture from pixmap: yes GL npot or rect textures: yes GL vertex program: yes GL fragment program: yes GL vertex buffer object: yes GL framebuffer object: yes GL version is 1.4+: yes Unity 3D supported: yes One suggestion was to do a sudo apt-get --purge remove nvidia* and that resulted in a scrambled screen on boot and a non-bootable installation. Pressing the Delete key on boot allowed me to access the recovery console and do a sudo apt-get install nvidia-current, which brought me back to a working, bootable system. Another suggestion was to edit /etc/default/grub and change the line reading "GRUB_CMDLINE_LINUX_DEFAULT="quiet splash" to read "GRUB_CMDLINE_LINUX_DEFAULT="quiet splash vmalloc=192MB" thus allocating more video RAM. I did that, followed by a sudo update-grub and a re-boot. No change. Created a brand new standard user and logged on with that account, no change.

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• Dynamic LINQ in an Assembly Near By

  - by Ricardo Peres

  You may recall my post on Dynamic LINQ. I said then that you had to download Microsoft's samples and compile the DynamicQuery project (or just grab my copy), but there's another way. It turns out Microsoft included the Dynamic LINQ classes in the System.Web.Extensions assembly, not the one from ASP.NET 2.0, but the one that was included with ASP.NET 3.5! The only problem is that all types are private: Here's how to use it: Assembly asm = typeof(UpdatePanel).Assembly; Type dynamicExpressionType = asm.GetType("System.Web.Query.Dynamic.DynamicExpression"); MethodInfo parseLambdaMethod = dynamicExpressionType.GetMethods(BindingFlags.Public | BindingFlags.Static).Where(m = (m.Name == "ParseLambda") && (m.GetParameters().Length == 2)).Single().MakeGenericMethod(typeof(DateTime), typeof(Boolean)); Func filterExpression = (parseLambdaMethod.Invoke(null, new Object [] { "Year == 2010", new Object [ 0 ] }) as Expression).Compile(); List list = new List { new DateTime(2010, 1, 1), new DateTime(1999, 1, 12), new DateTime(1900, 10, 10), new DateTime(1900, 2, 20), new DateTime(2012, 5, 5), new DateTime(2012, 1, 20) }; IEnumerable filteredDates = list.Where(filterExpression); SyntaxHighlighter.config.clipboardSwf = 'http://alexgorbatchev.com/pub/sh/2.0.320/scripts/clipboard.swf'; SyntaxHighlighter.brushes.CSharp.aliases = ['c#', 'c-sharp', 'csharp']; SyntaxHighlighter.all();

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• Is duck typing a subset of polymorphism

  - by Raynos

  From Polymorphism on WIkipedia In computer science, polymorphism is a programming language feature that allows values of different data types to be handled using a uniform interface. From duck typing on Wikipedia In computer programming with object-oriented programming languages, duck typing is a style of dynamic typing in which an object's current set of methods and properties determines the valid semantics, rather than its inheritance from a particular class or implementation of a specific interface. My interpretation is that based on duck typing, the objects methods/properties determine the valid semantics. Meaning that the objects current shape determines the interface it upholds. From polymorphism you can say a function is polymorphic if it accepts multiple different data types as long as they uphold an interface. So if a function can duck type, it can accept multiple different data types and operate on them as long as those data types have the correct methods/properties and thus uphold the interface. (Usage of the term interface is meant not as a code construct but more as a descriptive, documenting construct) What is the correct relationship between ducktyping and polymorphism ? If a language can duck type, does it mean it can do polymorphism ?

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• General Overview of Design Pattern Types

  Typically most software engineering design patterns fall into one of three categories in regards to types. Three types of software design patterns include: Creational Type Patterns Structural Type Patterns Behavioral Type Patterns The Creational Pattern type is geared toward defining the preferred methods for creating new instances of objects. An example of this type is the Singleton Pattern. The Singleton Pattern can be used if an application only needs one instance of a class. In addition, this singular instance also needs to be accessible across an application. The benefit of the Singleton Pattern is that you control both instantiation and access using this pattern. The Structural Pattern type is a way to describe the hierarchy of objects and classes so that they can be consolidated into a larger structure. An example of this type is the Façade Pattern.  The Façade Pattern is used to define a base interface so that all other interfaces inherit from the parent interface. This can be used to simplify a number of similar object interactions into one single standard interface. The Behavioral Pattern Type deals with communication between objects. An example of this type is the State Design Pattern. The State Design Pattern enables objects to alter functionality and processing based on the internal state of the object at a given time.

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• Making Sense of ASP.NET Paths

  - by Renso

  Making Sense of ASP.NET Paths ASP.Net includes quite a plethora of properties to retrieve path information about the current request, control and application. There's a ton of information available about paths on the Request object, some of it appearing to overlap and some of it buried several levels down, and it can be confusing to find just the right path that you are looking for. To keep things straight I thought it a good idea to summarize the path options along with descriptions and example paths. I wrote a post about this a long time ago in 2004 and I find myself frequently going back to that page to quickly figure out which path I’m looking for in processing the current URL. Apparently a lot of people must be doing the same, because the original post is the second most visited even to this date on this blog to the tune of nearly 500 hits per day. So, I decided to update and expand a bit on the original post with a little more information and clarification based on the original comments. Request Object Paths Available Here's a list of the Path related properties on the Request object (and the Page object). Assume a path like http://www.west-wind.com/webstore/admin/paths.aspx for the paths below where webstore is the name of the virtual. Request Property Description and Value ApplicationPath Returns the web root-relative logical path to the virtual root of this app. /webstore/ PhysicalApplicationPath Returns local file system path of the virtual root for this app. c:\inetpub\wwwroot\webstore PhysicalPath Returns the local file system path to the current script or path. c:\inetpub\wwwroot\webstore\admin\paths.aspx Path FilePath CurrentExecutionFilePath All of these return the full root relative logical path to the script page including path and scriptname. CurrentExcecutionFilePath will return the ‘current’ request path after a Transfer/Execute call while FilePath will always return the original request’s path. /webstore/admin/paths.aspx AppRelativeCurrentExecutionFilePath Returns an ASP.NET root relative virtual path to the script or path for the current request. If in  a Transfer/Execute call the transferred Path is returned. ~/admin/paths.aspx PathInfo Returns any extra path following the script name. If no extra path is provided returns the root-relative path (returns text in red below). string.Empty if no PathInfo is available. /webstore/admin/paths.aspx/ExtraPathInfo RawUrl Returns the full root relative URL including querystring and extra path as a string. /webstore/admin/paths.aspx?sku=wwhelp40 Url Returns a fully qualified URL including querystring and extra path. Note this is a Uri instance rather than string. http://www.west-wind.com/webstore/admin/paths.aspx?sku=wwhelp40 UrlReferrer The fully qualified URL of the page that sent the request. This is also a Uri instance and this value is null if the page was directly accessed by typing into the address bar or using an HttpClient based Referrer client Http header. http://www.west-wind.com/webstore/default.aspx?Info Control.TemplateSourceDirectory Returns the logical path to the folder of the page, master or user control on which it is called. This is useful if you need to know the path only to a Page or control from within the control. For non-file controls this returns the Page path. /webstore/admin/ As you can see there’s a ton of information available there for each of the three common path formats: Physical Path is an OS type path that points to a path or file on disk. Logical Path is a Web path that is relative to the Web server’s root. It includes the virtual plus the application relative path. ~/ (Root-relative) Path is an ASP.NET specific path that includes ~/ to indicate the virtual root Web path. ASP.NET can convert virtual paths into either logical paths using Control.ResolveUrl(), or physical paths using Server.MapPath(). Root relative paths are useful for specifying portable URLs that don’t rely on relative directory structures and very useful from within control or component code. You should be able to get any necessary format from ASP.NET from just about any path or script using these mechanisms. ~/ Root Relative Paths and ResolveUrl() and ResolveClientUrl() ASP.NET supports root-relative virtual path syntax in most of its URL properties in Web Forms. So you can easily specify a root relative path in a control rather than a location relative path: <asp:Image runat="server" ID="imgHelp" ImageUrl="~/images/help.gif" /> ASP.NET internally resolves this URL by using ResolveUrl("~/images/help.gif") to arrive at the root-relative URL of /webstore/images/help.gif which uses the Request.ApplicationPath as the basepath to replace the ~. By convention any custom Web controls also should use ResolveUrl() on URL properties to provide the same functionality. In your own code you can use Page.ResolveUrl() or Control.ResolveUrl() to accomplish the same thing: string imgPath = this.ResolveUrl("~/images/help.gif"); imgHelp.ImageUrl = imgPath; Unfortunately ResolveUrl() is limited to WebForm pages, so if you’re in an HttpHandler or Module it’s not available. ASP.NET Mvc also has it’s own more generic version of ResolveUrl in Url.Decode: <script src="<%= Url.Content("~/scripts/new.js") %>" type="text/javascript"></script> which is part of the UrlHelper class. In ASP.NET MVC the above sort of syntax is actually even more crucial than in WebForms due to the fact that views are not referencing specific pages but rather are often path based which can lead to various variations on how a particular view is referenced. In a Module or Handler code Control.ResolveUrl() unfortunately is not available which in retrospect seems like an odd design choice – URL resolution really should happen on a Request basis not as part of the Page framework. Luckily you can also rely on the static VirtualPathUtility class: string path = VirtualPathUtility.ToAbsolute("~/admin/paths.aspx"); VirtualPathUtility also many other quite useful methods for dealing with paths and converting between the various kinds of paths supported. One thing to watch out for is that ToAbsolute() will throw an exception if a query string is provided and doesn’t work on fully qualified URLs. I wrote about this topic with a custom solution that works fully qualified URLs and query strings here (check comments for some interesting discussions too). Similar to ResolveUrl() is ResolveClientUrl() which creates a fully qualified HTTP path that includes the protocol and domain name. It’s rare that this full resolution is needed but can be useful in some scenarios. Mapping Virtual Paths to Physical Paths with Server.MapPath() If you need to map root relative or current folder relative URLs to physical URLs or you can use HttpContext.Current.Server.MapPath(). Inside of a Page you can do the following: string physicalPath = Server.MapPath("~/scripts/ww.jquery.js")); MapPath is pretty flexible and it understands both ASP.NET style virtual paths as well as plain relative paths, so the following also works. string physicalPath = Server.MapPath("scripts/silverlight.js"); as well as dot relative syntax: string physicalPath = Server.MapPath("../scripts/jquery.js"); Once you have the physical path you can perform standard System.IO Path and File operations on the file. Remember with physical paths and IO or copy operations you need to make sure you have permissions to access files and folders based on the Web server user account that is active (NETWORK SERVICE, ASPNET typically). Note the Server.MapPath will not map up beyond the virtual root of the application for security reasons. Server and Host Information Between these settings you can get all the information you may need to figure out where you are at and to build new Url if necessary. If you need to build a URL completely from scratch you can get access to information about the server you are accessing: Server Variable Function and Example SERVER_NAME The of the domain or IP Address wwww.west-wind.com or 127.0.0.1 SERVER_PORT The port that the request runs under. 80 SERVER_PORT_SECURE Determines whether https: was used. 0 or 1 APPL_MD_PATH ADSI DirectoryServices path to the virtual root directory. Note that LM typically doesn’t work for ADSI access so you should replace that with LOCALHOST or the machine’s NetBios name. /LM/W3SVC/1/ROOT/webstore Request.Url and Uri Parsing If you still need more control over the current request URL or  you need to create new URLs from an existing one, the current Request.Url Uri property offers a lot of control. Using the Uri class and UriBuilder makes it easy to retrieve parts of a URL and create new URLs based on existing URL. The UriBuilder class is the preferred way to create URLs – much preferable over creating URIs via string concatenation. Uri Property Function Scheme The URL scheme or protocol prefix. http or https Port The port if specifically specified. DnsSafeHost The domain name or local host NetBios machine name www.west-wind.com or rasnote LocalPath The full path of the URL including script name and extra PathInfo. /webstore/admin/paths.aspx Query The query string if any ?id=1 The Uri class itself is great for retrieving Uri parts, but most of the properties are read only if you need to modify a URL in order to change it you can use the UriBuilder class to load up an existing URL and modify it to create a new one. Here are a few common operations I’ve needed to do to get specific URLs: Convert the Request URL to an SSL/HTTPS link For example to take the current request URL and converted  it to a secure URL can be done like this: UriBuilder build = new UriBuilder(Request.Url); build.Scheme = "https"; build.Port = -1; // don't inject portUri newUri = build.Uri; string newUrl = build.ToString(); Retrieve the fully qualified URL without a QueryString AFAIK, there’s no native routine to retrieve the current request URL without the query string. It’s easy to do with UriBuilder however: UriBuilder builder = newUriBuilder(Request.Url); builder.Query = ""; stringlogicalPathWithoutQuery = builder.ToString();

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• Silverlight Cream for May 30, 2010 -- #873

  - by Dave Campbell

  In this Issue: Matthias Shapiro, Colin Blair(-2-), Mike Snow, Marlon Grech, Victor Gaudioso. Shoutout: If you're going to be anywhere near Mission Viejo, California on June 19th, set your calendar for this Victor Gaudioso event: New Speaking Event: Microsoft Book Signing/Silverlight 4 Presentation SilverLaw has another example of his Flexible surface app up: Drag & Drop Flexible Surface - Silverlight 4 From SilverlightCream.com: Silverlight 4 Binding and StringFormat in XAML Matthias Shapiro has a discussion posted about StringFormat binding in Silverlight 4 ... he dug in hard on this... well worth a read. View Model Collection Properties for WCF RIA Services Colin Blair is discussing some possibilities for exposing collections of entities from the ViewModel... his favorite: PagedCollectionView. The next post discusses this deeper. Advanced Paged Collection View Colin Blair continues in more depth on the PagedCollectionView, this time handling paging, sorting, and multiple loads. Silverlight Tip of the day #25 – Detecting Validation Errors on Submit Mike Snow's latest Tip of the Day is up and is about validation - specifically validating after your user has pressed "OK" INotifyPropertyChanged… I am fed up of handling events just to know when a property changed Marlon Grech has an Rx-less solution to code notifications of properties changing... this is a WPF and Silverlight solution and all the code is downloadable. New Silverlight Video Tutorial: How to Add Multiple BitmapEffects to One Object Victor Gaudioso's latest outing is in response to a query from a reader and is a video tutorial showing how to add multiple bitmap effects to one object. Stay in the 'Light! Twitter SilverlightNews | Twitter WynApse | WynApse.com | Tagged Posts | SilverlightCream Join me @ SilverlightCream | Phoenix Silverlight User Group Technorati Tags: Silverlight    Silverlight 3    Silverlight 4    Windows Phone MIX10

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• Using Take and skip keyword to filter records in LINQ

  - by vik20000in

  In LINQ we can use the take keyword to filter out the number of records that we want to retrieve from the query. Let’s say we want to retrieve only the first 5 records for the list or array then we can use the following query     int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 };     var first3Numbers = numbers.Take(3); The TAKE keyword can also be easily applied to list of object in the following way. var first3WAOrders = (         from cust in customers         from order in cust.Orders         select cust ) .Take(3); [Note in the query above we are using the order clause so that the data is first ordered based on the orders field and then the first 3 records are taken. In both the above example we have been able to filter out data based on the number of records we want to fetch. But in both the cases we were fetching the records from the very beginning. But there can be some requirements whereby we want to fetch the records after skipping some of the records like in paging. For this purpose LINQ has provided us with the skip method which skips the number of records passed as parameter in the result set. int[] numbers = { 5, 4, 1, 3, 9, 8, 6, 7, 2, 0 }; var allButFirst4Numbers = numbers.Skip(4); The SKIP keyword can also be easily applied to list of object in the following way. var first3WAOrders = (         from cust in customers         from order in cust.Orders         select cust ).Skip(3);  Vikram

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• A Reusable Builder Class for Javascript Testing

  - by Liam McLennan

  Continuing on my series of builders for C# and Ruby here is the solution in Javascript. This is probably the implementation with which I am least happy. There are several parts that did not seem to fit the language. This time around I didn’t bother with a testing framework, I just append some values to the page with jQuery. Here is the test code: var initialiseBuilder = function() { var builder = builderConstructor(); builder.configure({ 'Person': function() { return {name: 'Liam', age: 26}}, 'Property': function() { return {street: '127 Creek St', manager: builder.a('Person') }} }); return builder; }; var print = function(s) { $('body').append(s + '<br/>'); }; var build = initialiseBuilder(); // get an object liam = build.a('Person'); print(liam.name + ' is ' + liam.age); // get a modified object liam = build.a('Person', function(person) { person.age = 999; }); print(liam.name + ' is ' + liam.age); home = build.a('Property'); print(home.street + ' manager: ' + home.manager.name); and the implementation: var builderConstructor = function() { var that = {}; var defaults = {}; that.configure = function(d) { defaults = d; }; that.a = function(type, modifier) { var o = defaults[type](); if (modifier) { modifier(o); } return o; }; return that; }; I still like javascript’s syntax for anonymous methods, defaults[type]() is much clearer than the Ruby equivalent @defaults[klass].call(). You can see the striking similarity between Ruby hashes and javascript objects. I also prefer modifier(o) to the equivalent Ruby, yield o.

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• The fastest way to resize images from ASP.NET. And it’s (more) supported-ish.

  - by Bertrand Le Roy

  I’ve shown before how to resize images using GDI, which is fairly common but is explicitly unsupported because we know of very real problems that this can cause. Still, many sites still use that method because those problems are fairly rare, and because most people assume it’s the only way to get the job done. Plus, it works in medium trust. More recently, I’ve shown how you can use WPF APIs to do the same thing and get JPEG thumbnails, only 2.5 times faster than GDI (even now that GDI really ultimately uses WIC to read and write images). The boost in performance is great, but it comes at a cost, that you may or may not care about: it won’t work in medium trust. It’s also just as unsupported as the GDI option. What I want to show today is how to use the Windows Imaging Components from ASP.NET APIs directly, without going through WPF. The approach has the great advantage that it’s been tested and proven to scale very well. The WIC team tells me you should be able to call support and get answers if you hit problems. Caveats exist though. First, this is using interop, so until a signed wrapper sits in the GAC, it will require full trust. Second, the APIs have a very strong smell of native code and are definitely not .NET-friendly. And finally, the most serious problem is that older versions of Windows don’t offer MTA support for image decoding. MTA support is only available on Windows 7, Vista and Windows Server 2008. But on 2003 and XP, you’ll only get STA support. that means that the thread safety that we so badly need for server applications is not guaranteed on those operating systems. To make it work, you’d have to spin specialized threads yourself and manage the lifetime of your objects, which is outside the scope of this article. We’ll assume that we’re fine with al this and that we’re running on 7 or 2008 under full trust. Be warned that the code that follows is not simple or very readable. This is definitely not the easiest way to resize an image in .NET. Wrapping native APIs such as WIC in a managed wrapper is never easy, but fortunately we won’t have to: the WIC team already did it for us and released the results under MS-PL. The InteropServices folder, which contains the wrappers we need, is in the WicCop project but I’ve also included it in the sample that you can download from the link at the end of the article. In order to produce a thumbnail, we first have to obtain a decoding frame object that WIC can use. Like with WPF, that object will contain the command to decode a frame from the source image but won’t do the actual decoding until necessary. Getting the frame is done by reading the image bytes through a special WIC stream that you can obtain from a factory object that we’re going to reuse for lots of other tasks: var photo = File.ReadAllBytes(photoPath); var factory = (IWICComponentFactory)new WICImagingFactory(); var inputStream = factory.CreateStream(); inputStream.InitializeFromMemory(photo, (uint)photo.Length); var decoder = factory.CreateDecoderFromStream( inputStream, null, WICDecodeOptions.WICDecodeMetadataCacheOnLoad); var frame = decoder.GetFrame(0); We can read the dimensions of the frame using the following (somewhat ugly) code: uint width, height; frame.GetSize(out width, out height); This enables us to compute the dimensions of the thumbnail, as I’ve shown in previous articles. We now need to prepare the output stream for the thumbnail. WIC requires a special kind of stream, IStream (not implemented by System.IO.Stream) and doesn’t directlyunderstand .NET streams. It does provide a number of implementations but not exactly what we need here. We need to output to memory because we’ll want to persist the same bytes to the response stream and to a local file for caching. The memory-bound version of IStream requires a fixed-length buffer but we won’t know the length of the buffer before we resize. To solve that problem, I’ve built a derived class from MemoryStream that also implements IStream. The implementation is not very complicated, it just delegates the IStream methods to the base class, but it involves some native pointer manipulation. Once we have a stream, we need to build the encoder for the output format, which could be anything that WIC supports. For web thumbnails, our only reasonable options are PNG and JPEG. I explored PNG because it’s a lossless format, and because WIC does support PNG compression. That compression is not very efficient though and JPEG offers good quality with much smaller file sizes. On the web, it matters. I found the best PNG compression option (adaptive) to give files that are about twice as big as 100%-quality JPEG (an absurd setting), 4.5 times bigger than 95%-quality JPEG and 7 times larger than 85%-quality JPEG, which is more than acceptable quality. As a consequence, we’ll use JPEG. The JPEG encoder can be prepared as follows: var encoder = factory.CreateEncoder( Consts.GUID_ContainerFormatJpeg, null); encoder.Initialize(outputStream, WICBitmapEncoderCacheOption.WICBitmapEncoderNoCache); The next operation is to create the output frame: IWICBitmapFrameEncode outputFrame; var arg = new IPropertyBag2[1]; encoder.CreateNewFrame(out outputFrame, arg); Notice that we are passing in a property bag. This is where we’re going to specify our only parameter for encoding, the JPEG quality setting: var propBag = arg[0]; var propertyBagOption = new PROPBAG2[1]; propertyBagOption[0].pstrName = "ImageQuality"; propBag.Write(1, propertyBagOption, new object[] { 0.85F }); outputFrame.Initialize(propBag); We can then set the resolution for the thumbnail to be 96, something we weren’t able to do with WPF and had to hack around: outputFrame.SetResolution(96, 96); Next, we set the size of the output frame and create a scaler from the input frame and the computed dimensions of the target thumbnail: outputFrame.SetSize(thumbWidth, thumbHeight); var scaler = factory.CreateBitmapScaler(); scaler.Initialize(frame, thumbWidth, thumbHeight, WICBitmapInterpolationMode.WICBitmapInterpolationModeFant); The scaler is using the Fant method, which I think is the best looking one even if it seems a little softer than cubic (zoomed here to better show the defects): Cubic Fant Linear Nearest neighbor We can write the source image to the output frame through the scaler: outputFrame.WriteSource(scaler, new WICRect { X = 0, Y = 0, Width = (int)thumbWidth, Height = (int)thumbHeight }); And finally we commit the pipeline that we built and get the byte array for the thumbnail out of our memory stream: outputFrame.Commit(); encoder.Commit(); var outputArray = outputStream.ToArray(); outputStream.Close(); That byte array can then be sent to the output stream and to the cache file. Once we’ve gone through this exercise, it’s only natural to wonder whether it was worth the trouble. I ran this method, as well as GDI and WPF resizing over thirty twelve megapixel images for JPEG qualities between 70% and 100% and measured the file size and time to resize. Here are the results: Size of resized images   Time to resize thirty 12 megapixel images Not much to see on the size graph: sizes from WPF and WIC are equivalent, which is hardly surprising as WPF calls into WIC. There is just an anomaly for 75% for WPF that I noted in my previous article and that disappears when using WIC directly. But overall, using WPF or WIC over GDI represents a slight win in file size. The time to resize is more interesting. WPF and WIC get similar times although WIC seems to always be a little faster. Not surprising considering WPF is using WIC. The margin of error on this results is probably fairly close to the time difference. As we already knew, the time to resize does not depend on the quality level, only the size does. This means that the only decision you have to make here is size versus visual quality. This third approach to server-side image resizing on ASP.NET seems to converge on the fastest possible one. We have marginally better performance than WPF, but with some additional peace of mind that this approach is sanctioned for server-side usage by the Windows Imaging team. It still doesn’t work in medium trust. That is a problem and shows the way for future server-friendly managed wrappers around WIC. The sample code for this article can be downloaded from: http://weblogs.asp.net/blogs/bleroy/Samples/WicResize.zip The benchmark code can be found here (you’ll need to add your own images to the Images directory and then add those to the project, with content and copy if newer in the properties of the files in the solution explorer): http://weblogs.asp.net/blogs/bleroy/Samples/WicWpfGdiImageResizeBenchmark.zip WIC tools can be downloaded from: http://code.msdn.microsoft.com/wictools To conclude, here are some of the resized thumbnails at 85% fant:

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• How should I design a correct OO design in case of a Business-logic wide operation

  - by Mithir

  EDIT: Maybe I should ask the question in a different way. in light of ammoQ's comment, I realize that I've done something like suggested which is kind of a fix and it is fine by me. But I still want to learn for the future, so that if I develop new code for operations similar to this, I can design it correctly from the start. So, if I got the following characteristics: The relevant input is composed from data which is connected to several different business objects All the input data is validated and cross-checked Attempts are made in order to insert the data to the DB All this is just a single operation from Business side prospective, meaning all of the cross checking and validations are just side effects. I can't think of any other way but some sort of Operator/Coordinator kind of Object which activates the entire procedure, but then I fall into a Functional-Decomposition kind of code. so is there a better way in doing this? Original Question In our system we have many complex operations which involve many validations and DB activities. One of the main Business functionality could have been designed better. In short, there were no separation of layers, and the code would only work from the scenario in which it was first designed at, and now there were more scenarios (like requests from an API or from other devices) So I had to redesign. I found myself moving all the DB code to objects which acts like Business to DB objects, and I've put all the business logic in an Operator kind of a class, which I've implemented like this: First, I created an object which will hold all the information needed for the operation let's call it InformationObject. Then I created an OperatorObject which will take the InformationObject as a parameter and act on it. The OperatorObject should activate different objects and validate or check for existence or any scenario in which the business logic is compromised and then make the operation according to the information on the InformationObject. So my question is - Is this kind of implementation correct? PS, this Operator only works on a single Business-wise Operation.

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• Overriding GetHashCode in a mutable struct - What NOT to do?

  - by Kyle Baran

  I am using the XNA Framework to make a learning project. It has a Point struct which exposes an X and Y value; for the purpose of optimization, it breaks the rules for proper struct design, since its a mutable struct. As Marc Gravell, John Skeet, and Eric Lippert point out in their respective posts about GetHashCode() (which Point overrides), this is a rather bad thing, since if an object's values change while its contained in a hashmap (ie, LINQ queries), it can become "lost". However, I am making my own Point3D struct, following the design of Point as a guideline. Thus, it too is a mutable struct which overrides GetHashCode(). The only difference is that mine exposes and int for X, Y, and Z values, but is fundamentally the same. The signatures are below: public struct Point3D : IEquatable<Point3D> { public int X; public int Y; public int Z; public static bool operator !=(Point3D a, Point3D b) { } public static bool operator ==(Point3D a, Point3D b) { } public Point3D Zero { get; } public override int GetHashCode() { } public override bool Equals(object obj) { } public bool Equals(Point3D other) { } public override string ToString() { } } I have tried to break my struct in the way they describe, namely by storing it in a List<Point3D>, as well as changing the value via a method using ref, but I did not encounter they behavior they warn about (maybe a pointer might allow me to break it?). Am I being too cautious in my approach, or should I be okay to use it as is?

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• Unity – Part 5: Injecting Values

  - by Ricardo Peres

  Introduction This is the fifth post on Unity. You can find the introductory post here, the second post, on dependency injection here, a third one on Aspect Oriented Programming (AOP) here and the latest so far, on writing custom extensions, here. This time we will talk about injecting simple values. An Inversion of Control (IoC) / Dependency Injector (DI) container like Unity can be used for things other than injecting complex class dependencies. It can also be used for setting property values or method/constructor parameters whenever a class is built. The main difference is that these values do not have a lifetime manager associated with them and do not come from the regular IoC registration store. Unlike, for instance, MEF, Unity won’t let you register as a dependency a string or an integer, so you have to take a different approach, which I will describe in this post. Scenario Let’s imagine we have a base interface that describes a logger – the same as in previous examples: 1: public interface ILogger 2: { 3: void Log(String message); 4: } And a concrete implementation that writes to a file: 1: public class FileLogger : ILogger 2: { 3: public String Filename 4: { 5: get; 6: set; 7: } 8:  9: #region ILogger Members 10:  11: public void Log(String message) 12: { 13: using (Stream file = File.OpenWrite(this.Filename)) 14: { 15: Byte[] data = Encoding.Default.GetBytes(message); 16: 17: file.Write(data, 0, data.Length); 18: } 19: } 20:  21: #endregion 22: } And let’s say we want the Filename property to come from the application settings (appSettings) section on the Web/App.config file. As usual with Unity, there is an extensibility point that allows us to automatically do this, both with code configuration or statically on the configuration file. Extending Injection We start by implementing a class that will retrieve a value from the appSettings by inheriting from ValueElement: 1: sealed class AppSettingsParameterValueElement : ValueElement, IDependencyResolverPolicy 2: { 3: #region Private methods 4: private Object CreateInstance(Type parameterType) 5: { 6: Object configurationValue = ConfigurationManager.AppSettings[this.AppSettingsKey]; 7:  8: if (parameterType != typeof(String)) 9: { 10: TypeConverter typeConverter = this.GetTypeConverter(parameterType); 11:  12: configurationValue = typeConverter.ConvertFromInvariantString(configurationValue as String); 13: } 14:  15: return (configurationValue); 16: } 17: #endregion 18:  19: #region Private methods 20: private TypeConverter GetTypeConverter(Type parameterType) 21: { 22: if (String.IsNullOrEmpty(this.TypeConverterTypeName) == false) 23: { 24: return (Activator.CreateInstance(TypeResolver.ResolveType(this.TypeConverterTypeName)) as TypeConverter); 25: } 26: else 27: { 28: return (TypeDescriptor.GetConverter(parameterType)); 29: } 30: } 31: #endregion 32:  33: #region Public override methods 34: public override InjectionParameterValue GetInjectionParameterValue(IUnityContainer container, Type parameterType) 35: { 36: Object value = this.CreateInstance(parameterType); 37: return (new InjectionParameter(parameterType, value)); 38: } 39: #endregion 40:  41: #region IDependencyResolverPolicy Members 42:  43: public Object Resolve(IBuilderContext context) 44: { 45: Type parameterType = null; 46:  47: if (context.CurrentOperation is ResolvingPropertyValueOperation) 48: { 49: ResolvingPropertyValueOperation op = (context.CurrentOperation as ResolvingPropertyValueOperation); 50: PropertyInfo prop = op.TypeBeingConstructed.GetProperty(op.PropertyName); 51: parameterType = prop.PropertyType; 52: } 53: else if (context.CurrentOperation is ConstructorArgumentResolveOperation) 54: { 55: ConstructorArgumentResolveOperation op = (context.CurrentOperation as ConstructorArgumentResolveOperation); 56: String args = op.ConstructorSignature.Split('(')[1].Split(')')[0]; 57: Type[] types = args.Split(',').Select(a => Type.GetType(a.Split(' ')[0])).ToArray(); 58: ConstructorInfo ctor = op.TypeBeingConstructed.GetConstructor(types); 59: parameterType = ctor.GetParameters().Where(p => p.Name == op.ParameterName).Single().ParameterType; 60: } 61: else if (context.CurrentOperation is MethodArgumentResolveOperation) 62: { 63: MethodArgumentResolveOperation op = (context.CurrentOperation as MethodArgumentResolveOperation); 64: String methodName = op.MethodSignature.Split('(')[0].Split(' ')[1]; 65: String args = op.MethodSignature.Split('(')[1].Split(')')[0]; 66: Type[] types = args.Split(',').Select(a => Type.GetType(a.Split(' ')[0])).ToArray(); 67: MethodInfo method = op.TypeBeingConstructed.GetMethod(methodName, types); 68: parameterType = method.GetParameters().Where(p => p.Name == op.ParameterName).Single().ParameterType; 69: } 70:  71: return (this.CreateInstance(parameterType)); 72: } 73:  74: #endregion 75:  76: #region Public properties 77: [ConfigurationProperty("appSettingsKey", IsRequired = true)] 78: public String AppSettingsKey 79: { 80: get 81: { 82: return ((String)base["appSettingsKey"]); 83: } 84:  85: set 86: { 87: base["appSettingsKey"] = value; 88: } 89: } 90: #endregion 91: } As you can see from the implementation of the IDependencyResolverPolicy.Resolve method, this will work in three different scenarios: When it is applied to a property; When it is applied to a constructor parameter; When it is applied to an initialization method. The implementation will even try to convert the value to its declared destination, for example, if the destination property is an Int32, it will try to convert the appSettings stored string to an Int32. Injection By Configuration If we want to configure injection by configuration, we need to implement a custom section extension by inheriting from SectionExtension, and registering our custom element with the name “appSettings”: 1: sealed class AppSettingsParameterInjectionElementExtension : SectionExtension 2: { 3: public override void AddExtensions(SectionExtensionContext context) 4: { 5: context.AddElement<AppSettingsParameterValueElement>("appSettings"); 6: } 7: } And on the configuration file, for setting a property, we use it like this: 1: <appSettings> 2: <add key="LoggerFilename" value="Log.txt"/> 3: </appSettings> 4: <unity xmlns="http://schemas.microsoft.com/practices/2010/unity"> 5: <container> 6: <register type="MyNamespace.ILogger, MyAssembly" mapTo="MyNamespace.ConsoleLogger, MyAssembly"/> 7: <register type="MyNamespace.ILogger, MyAssembly" mapTo="MyNamespace.FileLogger, MyAssembly" name="File"> 8: <lifetime type="singleton"/> 9: <property name="Filename"> 10: <appSettings appSettingsKey="LoggerFilename"/> 11: </property> 12: </register> 13: </container> 14: </unity> If we would like to inject the value as a constructor parameter, it would be instead: 1: <unity xmlns="http://schemas.microsoft.com/practices/2010/unity"> 2: <sectionExtension type="MyNamespace.AppSettingsParameterInjectionElementExtension, MyAssembly" /> 3: <container> 4: <register type="MyNamespace.ILogger, MyAssembly" mapTo="MyNamespace.ConsoleLogger, MyAssembly"/> 5: <register type="MyNamespace.ILogger, MyAssembly" mapTo="MyNamespace.FileLogger, MyAssembly" name="File"> 6: <lifetime type="singleton"/> 7: <constructor> 8: <param name="filename" type="System.String"> 9: <appSettings appSettingsKey="LoggerFilename"/> 10: </param> 11: </constructor> 12: </register> 13: </container> 14: </unity> Notice the appSettings section, where we add a LoggerFilename entry, which is the same as the one referred by our AppSettingsParameterInjectionElementExtension extension. For more advanced behavior, you can add a TypeConverterName attribute to the appSettings declaration, where you can pass an assembly qualified name of a class that inherits from TypeConverter. This class will be responsible for converting the appSettings value to a destination type. Injection By Attribute If we would like to use attributes instead, we need to create a custom attribute by inheriting from DependencyResolutionAttribute: 1: [Serializable] 2: [AttributeUsage(AttributeTargets.Parameter | AttributeTargets.Property, AllowMultiple = false, Inherited = true)] 3: public sealed class AppSettingsDependencyResolutionAttribute : DependencyResolutionAttribute 4: { 5: public AppSettingsDependencyResolutionAttribute(String appSettingsKey) 6: { 7: this.AppSettingsKey = appSettingsKey; 8: } 9:  10: public String TypeConverterTypeName 11: { 12: get; 13: set; 14: } 15:  16: public String AppSettingsKey 17: { 18: get; 19: private set; 20: } 21:  22: public override IDependencyResolverPolicy CreateResolver(Type typeToResolve) 23: { 24: return (new AppSettingsParameterValueElement() { AppSettingsKey = this.AppSettingsKey, TypeConverterTypeName = this.TypeConverterTypeName }); 25: } 26: } As for file configuration, there is a mandatory property for setting the appSettings key and an optional TypeConverterName  for setting the name of a TypeConverter. Both the custom attribute and the custom section return an instance of the injector AppSettingsParameterValueElement that we implemented in the first place. Now, the attribute needs to be placed before the injected class’ Filename property: 1: public class FileLogger : ILogger 2: { 3: [AppSettingsDependencyResolution("LoggerFilename")] 4: public String Filename 5: { 6: get; 7: set; 8: } 9:  10: #region ILogger Members 11:  12: public void Log(String message) 13: { 14: using (Stream file = File.OpenWrite(this.Filename)) 15: { 16: Byte[] data = Encoding.Default.GetBytes(message); 17: 18: file.Write(data, 0, data.Length); 19: } 20: } 21:  22: #endregion 23: } Or, if we wanted to use constructor injection: 1: public class FileLogger : ILogger 2: { 3: public String Filename 4: { 5: get; 6: set; 7: } 8:  9: public FileLogger([AppSettingsDependencyResolution("LoggerFilename")] String filename) 10: { 11: this.Filename = filename; 12: } 13:  14: #region ILogger Members 15:  16: public void Log(String message) 17: { 18: using (Stream file = File.OpenWrite(this.Filename)) 19: { 20: Byte[] data = Encoding.Default.GetBytes(message); 21: 22: file.Write(data, 0, data.Length); 23: } 24: } 25:  26: #endregion 27: } Usage Just do: 1: ILogger logger = ServiceLocator.Current.GetInstance<ILogger>("File"); And off you go! A simple way do avoid hardcoded values in component registrations. Of course, this same concept can be applied to registry keys, environment values, XML attributes, etc, etc, just change the implementation of the AppSettingsParameterValueElement class. Next stop: custom lifetime managers.

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• Using Table-Valued Parameters With SQL Server Reporting Services

  - by Jesse

  In my last post I talked about using table-valued parameters to pass a list of integer values to a stored procedure without resorting to using comma-delimited strings and parsing out each value into a TABLE variable. In this post I’ll extend the “Customer Transaction Summary” report example to see how we might leverage this same stored procedure from within an SQL Server Reporting Services (SSRS) report. I’ve worked with SSRS off and on for the past several years and have generally found it to be a very useful tool for building nice-looking reports for end users quickly and easily. That said, I’ve been frustrated by SSRS from time to time when seemingly simple things are difficult to accomplish or simply not supported at all. I thought that using table-valued parameters from within a SSRS report would be simple, but unfortunately I was wrong. Customer Transaction Summary Example Let’s take the “Customer Transaction Summary” report example from the last post and try to plug that same stored procedure into an SSRS report. Our report will have three parameters: Start Date – beginning of the date range for which the report will summarize customer transactions End Date – end of the date range for which the report will summarize customer transactions Customer Ids – One or more customer Ids representing the customers that will be included in the report The simplest way to get started with this report will be to create a new dataset and point it at our Customer Transaction Summary report stored procedure (note that I’m using SSRS 2012 in the screenshots below, but there should be little to no difference with SSRS 2008): When you initially create this dataset the SSRS designer will try to invoke the stored procedure to determine what the parameters and output fields are for you automatically. As part of this process the following dialog pops-up: Obviously I can’t use this dialog to specify a value for the ‘@customerIds’ parameter since it is of the IntegerListTableType user-defined type that we created in the last post. Unfortunately this really throws the SSRS designer for a loop, and regardless of what combination of Data Type, Pass Null Value, or Parameter Value I used here, I kept getting this error dialog with the message, "Operand type clash: nvarchar is incompatible with IntegerListTableType". This error message makes some sense considering that the nvarchar type is indeed incompatible with the IntegerListTableType, but there’s little clue given as to how to remedy the situation. I don’t know for sure, but I think that behind-the-scenes the SSRS designer is trying to give the @customerIds parameter an nvarchar-typed SqlParameter which is causing the issue. When I first saw this error I figured that this might just be a limitation of the dataset designer and that I’d be able to work around the issue by manually defining the parameters. I know that there are some special steps that need to be taken when invoking a stored procedure with a table-valued parameter from ADO .NET, so I figured that I might be able to use some custom code embedded in the report  to create a SqlParameter instance with the needed properties and value to make this work, but the “Operand type clash" error message persisted. The Text Query Approach Just because we’re using a stored procedure to create the dataset for this report doesn’t mean that we can’t use the ‘Text’ Query Type option and construct an EXEC statement that will invoke the stored procedure. In order for this to work properly the EXEC statement will also need to declare and populate an IntegerListTableType variable to pass into the stored procedure. Before I go any further I want to make one point clear: this is a really ugly hack and it makes me cringe to do it. Simply put, I strongly feel that it should not be this difficult to use a table-valued parameter with SSRS. With that said, let’s take a look at what we’ll have to do to make this work. Manually Define Parameters First, we’ll need to manually define the parameters for report by right-clicking on the ‘Parameters’ folder in the ‘Report Data’ window. We’ll need to define the ‘@startDate’ and ‘@endDate’ as simple date parameters. We’ll also create a parameter called ‘@customerIds’ that will be a mutli-valued Integer parameter: In the ‘Available Values’ tab we’ll point this parameter at a simple dataset that just returns the CustomerId and CustomerName of each row in the Customers table of the database or manually define a handful of Customer Id values to make available when the report runs. Once we have these parameters properly defined we can take another crack at creating the dataset that will invoke the ‘rpt_CustomerTransactionSummary’ stored procedure. This time we’ll choose the ‘Text’ query type option and put the following into the ‘Query’ text area: 1: exec('declare @customerIdList IntegerListTableType ' + @customerIdInserts + 2: ' EXEC rpt_CustomerTransactionSummary 3: @startDate=''' + @startDate + ''', 4: @endDate='''+ @endDate + ''', 5: @customerIds=@customerIdList')   By using the ‘Text’ query type we can enter any arbitrary SQL that we we want to and then use parameters and string concatenation to inject pieces of that query at run time. It can be a bit tricky to parse this out at first glance, but from the SSRS designer’s point of view this query defines three parameters: @customerIdInserts – This will be a Text parameter that we use to define INSERT statements that will populate the @customerIdList variable that is being declared in the SQL. This parameter won’t actually ever get passed into the stored procedure. I’ll go into how this will work in a bit. @startDate – This is a simple date parameter that will get passed through directly into the @startDate parameter of the stored procedure on line 3. @endDate – This is another simple data parameter that will get passed through into the @endDate parameter of the stored procedure on line 4. At this point the dataset designer will be able to correctly parse the query and should even be able to detect the fields that the stored procedure will return without needing to specify any values for query when prompted to. Once the dataset has been correctly defined we’ll have a @customerIdInserts parameter listed in the ‘Parameters’ tab of the dataset designer. We need to define an expression for this parameter that will take the values selected by the user for the ‘@customerIds’ parameter that we defined earlier and convert them into INSERT statements that will populate the @customerIdList variable that we defined in our Text query. In order to do this we’ll need to add some custom code to our report using the ‘Report Properties’ dialog: Any custom code defined in the Report Properties dialog gets embedded into the .rdl of the report itself and (unfortunately) must be written in VB .NET. Note that you can also add references to custom .NET assemblies (which could be written in any language), but that’s outside the scope of this post so we’ll stick with the “quick and dirty” VB .NET approach for now. Here’s the VB .NET code (note that any embedded code that you add here must be defined in a static/shared function, though you can define as many functions as you want): 1: Public Shared Function BuildIntegerListInserts(ByVal variableName As String, ByVal paramValues As Object()) As String 2: Dim insertStatements As New System.Text.StringBuilder() 3: For Each paramValue As Object In paramValues 4: insertStatements.AppendLine(String.Format("INSERT {0} VALUES ({1})", variableName, paramValue)) 5: Next 6: Return insertStatements.ToString() 7: End Function   This method takes a variable name and an array of objects. We use an array of objects here because that is how SSRS will pass us the values that were selected by the user at run-time. The method uses a StringBuilder to construct INSERT statements that will insert each value from the object array into the provided variable name. Once this method has been defined in the custom code for the report we can go back into the dataset designer’s Parameters tab and update the expression for the ‘@customerIdInserts’ parameter by clicking on the button with the “function” symbol that appears to the right of the parameter value. We’ll set the expression to: 1: =Code.BuildIntegerListInserts("@customerIdList ", Parameters!customerIds.Value)   In order to invoke our custom code method we simply need to invoke “Code.<method name>” and pass in any needed parameters. The first parameter needs to match the name of the IntegerListTableType variable that we used in the EXEC statement of our query. The second parameter will come from the Value property of the ‘@customerIds’ parameter (this evaluates to an object array at run time). Finally, we’ll need to edit the properties of the ‘@customerIdInserts’ parameter on the report to mark it as a nullable internal parameter so that users aren’t prompted to provide a value for it when running the report. Limitations And Final Thoughts When I first started looking into the text query approach described above I wondered if there might be an upper limit to the size of the string that can be used to run a report. Obviously, the size of the actual query could increase pretty dramatically if you have a parameter that has a lot of potential values or you need to support several different table-valued parameters in the same query. I tested the example Customer Transaction Summary report with 1000 selected customers without any issue, but your mileage may vary depending on how much data you might need to pass into your query. If you think that the text query hack is a lot of work just to use a table-valued parameter, I agree! I think that it should be a lot easier than this to use a table-valued parameter from within SSRS, but so far I haven’t found a better way. It might be possible to create some custom .NET code that could build the EXEC statement for a given set of parameters automatically, but exploring that will have to wait for another post. For now, unless there’s a really compelling reason or requirement to use table-valued parameters from SSRS reports I would probably stick with the tried and true “join-multi-valued-parameter-to-CSV-and-split-in-the-query” approach for using mutli-valued parameters in a stored procedure.

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• Using Microsoft's Chart Controls In An ASP.NET Application: Serializing Chart Data

  In most usage scenarios, the data displayed in a Microsoft Chart control comes from some dynamic source, such as from a database query. The appearance of the chart can be modified dynamically, as well; past installments in this article series showed how to programmatically customize the axes, labels, and other appearance-related settings. However, it is possible to statically define the chart's data and appearance strictly through the control's declarative markup. One of the demos examined in the Getting Started article rendered a column chart with seven columns whose labels and values were defined statically in the <asp:Series> tag's <Points> collection. Given this functionality, it should come as no surprise that the Microsoft Chart Controls also support serialization. Serialization is the process of persisting the state of a control or an object to some other medium, such as to disk. Deserialization is the inverse process, and involves taking the persisted data and recreating the control or object. With just a few lines of code you can persist the appearance settings, the data, or both to a file on disk or to any stream. Likewise, it takes just a few lines of codes to reconstitute a chart from the persisted information. This article shows how to use the Microsoft Chart Control's serialization functionality by examining a demo application that allows users to create custom charts, specifying the data to plot and some appearance-related settings. The user can then save a "snapshot" of this chart, which persists its appearance and data to a record in a database. From another page, users can view these saved chart snapshots. Read on to learn more! Read More >

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