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  • How to find unmapped properties in a NHibernate mapped class?

    - by haarrrgh
    I just had a NHibernate related problem where I forgot to map one property of a class. A very simplified example: public class MyClass { public virtual int ID { get; set; } public virtual string SomeText { get; set; } public virtual int SomeNumber { get; set; } } ...and the mapping file: <?xml version="1.0" encoding="utf-8" ?> <hibernate-mapping xmlns="urn:nhibernate-mapping-2.2" assembly="MyAssembly" namespace="MyAssembly.MyNamespace"> <class name="MyClass" table="SomeTable"> <property name="ID" /> <property name="SomeText" /> </class> </hibernate-mapping> In this simple example, you can see the problem at once: there is a property named "SomeNumber" in the class, but not in the mapping file. So NHibernate will not map it and it will always be zero. The real class had a lot more properties, so the problem was not as easy to see and it took me quite some time to figure out why SomeNumber always returned zero even though I was 100% sure that the value in the database was != zero. So, here is my question: Is there some simple way to find this out via NHibernate? Like a compiler warning when a class is mapped, but some of its properties are not. Or some query that I can run that shows me unmapped properties in mapped classes...you get the idea. (Plus, it would be nice if I could exclude some legacy columns that I really don't want mapped.)

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  • Why does the VS2005 debugger not report "base." values properly? (was "Why is this if statement fail

    - by Rawling
    I'm working on an existing class that is two steps derived from System.Windows.Forms.Combo box. The class overrides the Text property thus: public override string Text { get { return this.AccessibilityObject.Value; } set { if (base.Text != value) { base.Text = value; } } } The reason given for that "get" is this MS bug: http://support.microsoft.com/kb/814346 However, I'm more interested in the fact that the "if" doesn't work. There are times where "base.Text != value" is true and yet pressing F10 steps straight to the closing } of the "set" and the Text property is not changed. I've seen this both by just checking values in the debugger, and putting a conditional breakpoint on that only breaks when the "if" statement's predicate is true. How on earth can "if" go wrong? The class between this and ComboBox doesn't touch the Text property. The bug above shouldn't really be affecting anything - it says it's fixed in VS2005. Is the debugger showing different values than the program itself sees? Update I think I've found what is happening here. The debugger is reporting value incorrectly (including evaluating conditional breakpoints incorrectly). To see this, try the following pair of classes: class MyBase { virtual public string Text { get { return "BaseText"; } } } class MyDerived : MyBase { public override string Text { get { string test = base.Text; return "DerivedText"; } } } Put a breakpoint on the last return statement, then run the code and access that property. In my VS2005, hovering over base.Text gives the value "DerivedText", but the variable test has been correctly set to "BaseText". So, new question: why does the debugger not handle base properly, and how can I get it to?

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  • Doesn't this defeat the whole purpose of having read-only properties?

    - by flockofcode
    I know how to use properties and I understand that they implicitly call underlying get and set accessors, depending on whether we are writing to or reading from a property. static void Main(string[] args) { A a = new A(); (a.b).i = 100; } class A { private B _b = new B(); public B b { get { return _b; } } } class B { public int i; } What code (a.b).i = 100; essentially does is that first property’s get accessor returns a reference to an object _b, and once we have this reference, we are able to access _b’s members and change their values. Thus, in our example, having read only property only prevents outside code from changing the value of a reference variable _b, but it doesn’t prevent outside code from accessing _b’s members. So it seems that property can only detect whether we are trying to read from or write to a variable ( in our case variable _b ) located on the stack, while it’s not able to detect whether we’re trying to also write to members of an object to which the variable on the stack ( assuming this variable is of reference type ) points to. a) But doesn’t that defeat the whole purpose of having read-only properties? Wouldn’t it be more effective if properties had the ability to also detect whether we’re trying to access members of an object returned by get accessor( assuming backing field is of a reference type )? thank you

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  • Best practice when removing entity regarding mappedBy collections?

    - by Daniel Bleisteiner
    I'm still kind of undecided which is the best practice to handle em.remove(entity) with this entity being in several collections mapped using mappedBy in JPA. Consider an entity like a Property that references three other entities: a Descriptor, a BusinessObject and a Level entity. The mapping is defined using @ManyToOne in the Property entity and using @OneToMany(mappedBy...) in the other three objects. That inverse mapping is defined because there are some situations where I need to access those collections. Whenever I remove a Property using em.remove(prop) this element is not automatically removed from managed entities of the other three types. If I don't care about that and the following page load (webapp) doesn't reload those entities the Property is still found and some decisions might be taken that are no longer true. The inverse mappings may become quite large and though I don't want to use something like descriptor.getProperties().remove(prop) because it will load all those properties that might have been lazy loaded until then. So my currently preferred way is to refresh the entity if it is managed: if (em.contains(descriptor)) em.refresh(descriptor) - which unloads a possibly loaded collection and triggers a reload upon the next access. Is there another feasible way to handle all those mappedBy collections of already loaded entites?

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  • Force calling the derived class implementation within a generic function in C#?

    - by Adam Hardy
    Ok so I'm currently working with a set of classes that I don't have control over in some pretty generic functions using these objects. Instead of writing literally tens of functions that essentially do the same thing for each class I decided to use a generic function instead. Now the classes I'm dealing with are a little weird in that the derived classes share many of the same properties but the base class that they are derived from doesn't. One such property example is .Parent which exists on a huge number of derived classes but not on the base class and it is this property that I need to use. For ease of understanding I've created a small example as follows: class StandardBaseClass {} // These are simulating the SMO objects class StandardDerivedClass : StandardBaseClass { public object Parent { get; set; } } static class Extensions { public static object GetParent(this StandardDerivedClass sdc) { return sdc.Parent; } public static object GetParent(this StandardBaseClass sbc) { throw new NotImplementedException("StandardBaseClass does not contain a property Parent"); } // This is the Generic function I'm trying to write and need the Parent property. public static void DoSomething<T>(T foo) where T : StandardBaseClass { object Parent = ((T)foo).GetParent(); } } In the above example calling DoSomething() will throw the NotImplemented Exception in the base class's implementation of GetParent(), even though I'm forcing the cast to T which is a StandardDerivedClass. This is contrary to other casting behaviour where by downcasting will force the use of the base class's implementation. I see this behaviour as a bug. Has anyone else out there encountered this?

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  • EF4 querying through the generations

    - by Hans Kesting
    I have a model withs Parents, Children and Grandchildren, in a many-to-many relationship. Using this article I created POCO classes that work fine, except for one thing I can't yet figure out. When I query the Parents or Children directly using LINQ, the SQL reflects the LINQ query (a .Count() executes a COUNT in the database and so on) - fine. The Parent class has a Children property, to access it's children. But (and now for the problem) this doesn't expose an IQueryable interface but an ICollection. So when I access the Children property on a particular parent all the Parent's Children are read. Even worse, when I access the Grandchildren (theParent.Children.SelectMany(child => child.GrandChildren).Count()) then for each and every child a separate request is issued to select it's grandchildren. Changing the type of the Children property from ICollection to IQueryable doesn't solve this. Apart from missing needed methods like Add() and Remove(), EF just doesn't recognize the property then. Are there correct ways (as in: low database interaction) of querying through children (and what are they)? Or is this just not possible?

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  • ASP.NET Custom Control - Template Allowing Literal Content

    - by Bob Fincheimer
    I want my User Control to be able to have Literal Content inside of it. For Example: <fc:Text runat="server">Please enter your login information:</fc:Text> Currently the code for my user control is: <ParseChildren(True, "Content")> _ Partial Public Class ctrFormText Inherits FormControl Private _content As ArrayList <PersistenceMode(PersistenceMode.InnerDefaultProperty), _ DesignerSerializationVisibility(DesignerSerializationVisibility.Content), _ TemplateInstance(TemplateInstance.Single)> _ Public Property Content() As ArrayList Get If _content Is Nothing Then Return New ArrayList End If Return _content End Get Set(ByVal value As ArrayList) _content = value End Set End Property Protected Overrides Sub CreateChildControls() If _content IsNot Nothing Then ctrChildren.Controls.Clear() For Each i As Control In _content ctrChildren.Controls.Add(i) Next End If MyBase.CreateChildControls() End Sub End Class And when I put text inside this control (like above) i get this error: Parser Error Message: Literal content ('Please enter your login information to access CKMS:') is not allowed within a 'System.Collections.ArrayList'. This control could have other content than just the text, so making the Content property an attribute will not solve my problem. I found in some places that I need to implement a ControlBuilder Class, along with another class that implements IParserAccessor. Anyway I just want my default "Content" property to have all types of controls allowed in it, both literal and actual controls.

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  • Best way to create a collection of a class

    - by smartins
    I'm trying to create some classes that allow me to retrieve and manipulate a set of backups my application will create and manage. I've come up with the following code (not tested yet), but I'm not sure if it's the best way of accomplishing this or if there's any easier/better way. I'm using Delphi 2010. I have a class that holds the backup details (TBackupItem), then I need to have a class that will hold a collection of TBackupItem and finally I'll have a class that manages the reading and writing of backups and also exposes a property that accesses the collection of TBackupItem. type TBackupItem = class private FBackupProgram: string; FBackupProgramVersion: string; // There are more variables and properties but for the sake of simplicity I've listed only two public property BackupProgram: string read FBackupProgram write FBackupProgram; property BackupProgramVersion: string read FBackupProgramVersion write FBackupProgramVersion; end; TBackupsList = class(???) private // This class will hold a list of TBackupItem. What should I use to accomplish this? end; TBackupsManager = class(TObject) private FBackups: TBackupsList; public property Backups: TBackupsList read FBackups write FBackups; end; Do you guys have any comments and/or examples on the best way of accomplishing this? Thanks!

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  • Hibernate not loading associated object

    - by Noor
    Hi, i am trying to load a hibernate object ForumMessage but in it contain another object Users and the Users object is not being loaded. My ForumMessage Mapping File: <?xml version="1.0"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd"> <!-- Generated Jan 4, 2011 10:10:29 AM by Hibernate Tools 3.4.0.Beta1 --> <hibernate-mapping> <class name="com.BiddingSystem.Models.ForumMessage" table="FORUMMESSAGE"> <id name="ForumMessageId" type="long"> <column name="FORUMMESSAGEID" /> <generator class="native" /> </id> <property name="ForumMessage" type="java.lang.String"> <column name="FORUMMESSAGE" /> </property> <many-to-one name="User" class="com.BiddingSystem.Models.Users" fetch="join"> <column name="UserId" /> </many-to-one> <property name="DatePosted" type="java.util.Date"> <column name="DATEPOSTED" /> </property> <many-to-one name="Topic" class="com.BiddingSystem.Models.ForumTopic" fetch="join"> <column name="TopicId" /> </many-to-one> </class> </hibernate-mapping> and I am using the follwing code: Session session = gileadHibernateUtil.getSessionFactory().openSession(); SQL="from ForumMessage"; System.out.println(SQL); Query query=session.createQuery(SQL); System.out.println(query.list().size()); return new LinkedList <ForumMessage>(query.list());

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  • Hive performance increase

    - by Sagar Nikam
    I am dealing with a database (2.5 GB) having some tables only 40 row to some having 9 million rows data. when I am doing any query for large table it takes more time. I want results in less time small query on table which have 90 rows only-- hive> select count(*) from cidade; Time taken: 50.172 seconds hdfs-site.xml <configuration> <property> <name>dfs.replication</name> <value>3</value> <description>Default block replication. The actual number of replications can be specified when the file is created. The default is used if replication is not specified in create time. </description> </property> <property> <name>dfs.block.size</name> <value>131072</value> <description>Default block replication. The actual number of replications can be specified when the file is created. The default is used if replication is not specified in create time. </description> </property> </configuration> does these setting affects performance of hive? dfs.replication=3 dfs.block.size=131072 can i set it from hive prompt as hive>set dfs.replication=5 Is this value remains for a perticular session only ? or Is it better to change it in .xml file ?

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  • Log4j Logging to the Wrong Directory

    - by John
    I have a relatively complex log4j.xml configuration file with many appenders. Some machines the application runs on need a separate log directory, which is actually a mapped network drive. To get around this, we embed a system property as part of the filename in order to specify the directory. Here is an example: The "${user.dir}" part is set as a system property on each system, and is normally set to the root directory of the application. On some systems, this location is not the root of the application. The problem is that there is always one appender where this is not set, and the file appears not to write to the mapped drive. The rest of the appenders do write to the correct location per the system property. As a unit test, I set up our QA lab to hard-code the values for the appender above, and it worked: however, a different appender will then append to the wrong file. The mis-logged file is always the same for a given configuration: it is not a random file each time. My best educated guess is that there is a HashMap somewhere containing these appenders, and for some reason, the first one retrieved from the map does not have the property set. Our application does have custom system properties loading: the main() method loads a properties file and calls into System.setProperties(). My first instinct was to check the static initialization order, and to ensure the controller class with the main method does not call into log4j (directly or indirectly) before setting the properties just in case this was interfering with log4j's own initialization. Even removing all vestiges of log4j from the initialization logic, this error condition still occurs.

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  • AutoMapper strings to enum descriptions

    - by 6footunder
    Given the requirement: Take an object graph, set all enum type properties based on the processed value of a second string property. Convention dictates that the name of the source string property will be that of the enum property with a postfix of "Raw". By processed we mean we'll need to strip specified characters e.t.c. I've looked at custom formatters, value resolvers and type converters, none of which seems like a solution for this? We want to use AutoMapper as opposed to our own reflection routine for two reasons, a) it's used extensively throughout the rest of the project and b) it gives you recursive traversal ootb. -- Example -- Given the (simple) structure below, and this: var tmp = new SimpleClass { CountryRaw = "United States", Person = new Person { GenderRaw="Male" } }; var tmp2 = new SimpleClass(); Mapper.Map(tmp, tmp2); we'd expect tmp2's MappedCountry enum to be Country.UnitedStates and the Person property to have a gender of Gender.Male. public class SimpleClass1 { public string CountryRaw {get;set;} public Country MappedCountry {get;set;} public Person Person {get;set;} } public class Person { public string GenderRaw {get;set;} public Gender Gender {get;set;} public string Surname {get;set;} } public enum Country { UnitedStates = 1, NewZealand = 2 } public enum Gender { Male, Female, Unknown } Thanks

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  • "Cannot find the declaration of element 'beans'. at mvc-dispatcher-servlet.xml", but can when I copy, delete and re-paste?

    - by stevendao
    Running Maven, Eclipse, and Weblogic, when I try to Run As Server onto my local server, I get this error: "Cannot find the declaration of element 'beans'. at mvc-dispatcher-servlet.xml" Then, when I go back into the xml, select all, copy, delete, and paste, error goes away and I'm able to run the web app just fine on the server. Can anyone explain why? <beans xmlns="http://www.springframework.org/schema/beans" xmlns:context="http://www.springframework.org/schema/context" xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation=" http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd"> <context:component-scan base-package="src.srcc.sndao" /> <mvc:annotation-driven /> <bean class="org.springframework.web.servlet.view.InternalResourceViewResolver"> <property name="prefix"> <value>/WEB-INF/view/</value> </property> <property name="suffix"> <value>.jsp</value> </property> </bean> </beans>

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  • Wrong class type in objective C

    - by Max Hui
    I have a parent class and a child class. GameObjectBase (parent) GameObjectPlayer(child). When I override a method in Child class and call it using [myPlayerClass showNextFrame] It is calling the parent class one. It turns out in the debugger, I see the myPlayerClass was indeed class type GameObjectBase (which is the parent class) How come? GameObjectBase.h #import <Foundation/Foundation.h> #import "cocos2d.h" @class GameLayer; @interface GameObjectBase : NSObject { /* CCSprite *gameObjectSprite; // Sprite representing this game object GameLayer *parentGameLayer; */ // Reference of the game layer this object // belongs to } @property (nonatomic, assign) CCSprite *gameObjectSprite; @property (nonatomic, assign) GameLayer *parentGameLayer; // Class method. Autorelease + (id) initWithGameLayer:(GameLayer *) gamelayer imageFileName:(NSString *) fileName; // "Virtual methods" that the derived class should implement. // If not implemented, this method will be called and Assert game - (void) update: (ccTime) dt; - (void) showNextFrame; @end GameObjectPlayer.h #import <Foundation/Foundation.h> #import "GameObjectBase.h" @interface GameObjectPlayer : GameObjectBase { int direction; } @property (nonatomic) int direction; @end GameLayer.h #import "cocos2d.h" #import "GameObjectPlayer.h" @interface GameLayer : CCLayer { } // returns a CCScene that contains the GameLayer as the only child +(CCScene *) scene; @property (nonatomic, strong) GameObjectPlayer *player; @end When I call examine in debugger what type "temp" is in this function inside GameLayer class, it's giving parent class GameObjectBase instead of subclass GameObjectPlayer - (void) update:(ccTime) dt { GameObjectPlayer *temp = _player; [temp showNextFrame]; }

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  • Creating packages in code - Package Configurations

    Continuing my theme of building various types of packages in code, this example shows how to building a package with package configurations. Incidentally it shows you how to add a variable, and a connection too. It covers the five most common configurations: Configuration File Indirect Configuration File SQL Server Indirect SQL Server Environment Variable  For a general overview try the SQL Server Books Online Package Configurations topic. The sample uses a a simple helper function ApplyConfig to create or update a configuration, although in the example we will only ever create. The most useful knowledge is the configuration string (Configuration.ConfigurationString) that you need to set. Configuration Type Configuration String Description Configuration File The full path and file name of an XML configuration file. The file can contain one or more configuration and includes the target path and new value to set. Indirect Configuration File An environment variable the value of which contains full path and file name of an XML configuration file as per the Configuration File type described above. SQL Server A three part configuration string, with each part being quote delimited and separated by a semi-colon. -- The first part is the connection manager name. The connection tells you which server and database to look for the configuration table. -- The second part is the name of the configuration table. The table is of a standard format, use the Package Configuration Wizard to help create an example, or see the sample script files below. The table contains one or more rows or configuration items each with a target path and new value. -- The third and final part is the optional filter name. A configuration table can contain multiple configurations, and the filter is  literal value that can be used to group items together and act as a filter clause when configurations are being read. If you do not need a filter, just leave the value empty. Indirect SQL Server An environment variable the value of which is the three part configuration string as per the SQL Server type described above. Environment Variable An environment variable the value of which is the value to set in the package. This is slightly different to the other examples as the configuration definition in the package also includes the target information. In our ApplyConfig function this is the only example that actually supplies a target value for the Configuration.PackagePath property. The path is an XPath style path for the target property, \Package.Variables[User::Variable].Properties[Value], the equivalent of which can be seen in the screenshot below, with the object being our variable called Variable, and the property to set is the Value property of that variable object. The configurations as seen when opening the generated package in BIDS: The sample code creates the package, adds a variable and connection manager, enables configurations, and then adds our example configurations. The package is then saved to disk, useful for checking the package and testing, before finally executing, just to prove it is valid. There are some external resources used here, namely some environment variables and a table, see below for more details. namespace Konesans.Dts.Samples { using System; using Microsoft.SqlServer.Dts.Runtime; public class PackageConfigurations { public void CreatePackage() { // Create a new package Package package = new Package(); package.Name = "ConfigurationSample"; // Add a variable, the target for our configurations package.Variables.Add("Variable", false, "User", 0); // Add a connection, for SQL configurations // Add the SQL OLE-DB connection ConnectionManager connectionManagerOleDb = package.Connections.Add("OLEDB"); connectionManagerOleDb.Name = "SQLConnection"; connectionManagerOleDb.ConnectionString = "Provider=SQLOLEDB.1;Data Source=(local);Initial Catalog=master;Integrated Security=SSPI;"; // Add our example configurations, first must enable package setting package.EnableConfigurations = true; // Direct configuration file, see sample file this.ApplyConfig(package, "Configuration File", DTSConfigurationType.ConfigFile, "C:\\Temp\\XmlConfig.dtsConfig", string.Empty); // Indirect configuration file, the emvironment variable XmlConfigFileEnvironmentVariable // contains the path to the configuration file, e.g. C:\Temp\XmlConfig.dtsConfig this.ApplyConfig(package, "Indirect Configuration File", DTSConfigurationType.IConfigFile, "XmlConfigFileEnvironmentVariable", string.Empty); // Direct SQL Server configuration, uses the SQLConnection package connection to read // configurations from the [dbo].[SSIS Configurations] table, with a filter of "SampleFilter" this.ApplyConfig(package, "SQL Server", DTSConfigurationType.SqlServer, "\"SQLConnection\";\"[dbo].[SSIS Configurations]\";\"SampleFilter\";", string.Empty); // Indirect SQL Server configuration, the environment variable "SQLServerEnvironmentVariable" // contains the configuration string e.g. "SQLConnection";"[dbo].[SSIS Configurations]";"SampleFilter"; this.ApplyConfig(package, "Indirect SQL Server", DTSConfigurationType.ISqlServer, "SQLServerEnvironmentVariable", string.Empty); // Direct environment variable, the value of the EnvironmentVariable environment variable is // applied to the target property, the value of the "User::Variable" package variable this.ApplyConfig(package, "EnvironmentVariable", DTSConfigurationType.EnvVariable, "EnvironmentVariable", "\\Package.Variables[User::Variable].Properties[Value]"); #if DEBUG // Save package to disk, DEBUG only new Application().SaveToXml(String.Format(@"C:\Temp\{0}.dtsx", package.Name), package, null); Console.WriteLine(@"C:\Temp\{0}.dtsx", package.Name); #endif // Execute package package.Execute(); // Basic check for warnings foreach (DtsWarning warning in package.Warnings) { Console.WriteLine("WarningCode : {0}", warning.WarningCode); Console.WriteLine(" SubComponent : {0}", warning.SubComponent); Console.WriteLine(" Description : {0}", warning.Description); Console.WriteLine(); } // Basic check for errors foreach (DtsError error in package.Errors) { Console.WriteLine("ErrorCode : {0}", error.ErrorCode); Console.WriteLine(" SubComponent : {0}", error.SubComponent); Console.WriteLine(" Description : {0}", error.Description); Console.WriteLine(); } package.Dispose(); } /// <summary> /// Add or update an package configuration. /// </summary> /// <param name="package">The package.</param> /// <param name="name">The configuration name.</param> /// <param name="type">The type of configuration</param> /// <param name="setting">The configuration setting.</param> /// <param name="target">The target of the configuration, leave blank if not required.</param> internal void ApplyConfig(Package package, string name, DTSConfigurationType type, string setting, string target) { Configurations configurations = package.Configurations; Configuration configuration; if (configurations.Contains(name)) { configuration = configurations[name]; } else { configuration = configurations.Add(); } configuration.Name = name; configuration.ConfigurationType = type; configuration.ConfigurationString = setting; configuration.PackagePath = target; } } } The following table lists the environment variables required for the full example to work along with some sample values. Variable Sample value EnvironmentVariable 1 SQLServerEnvironmentVariable "SQLConnection";"[dbo].[SSIS Configurations]";"SampleFilter"; XmlConfigFileEnvironmentVariable C:\Temp\XmlConfig.dtsConfig Sample code, package and configuration file. ConfigurationApplication.cs ConfigurationSample.dtsx XmlConfig.dtsConfig

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  • Dynamic Types and DynamicObject References in C#

    - by Rick Strahl
    I've been working a bit with C# custom dynamic types for several customers recently and I've seen some confusion in understanding how dynamic types are referenced. This discussion specifically centers around types that implement IDynamicMetaObjectProvider or subclass from DynamicObject as opposed to arbitrary type casts of standard .NET types. IDynamicMetaObjectProvider types  are treated special when they are cast to the dynamic type. Assume for a second that I've created my own implementation of a custom dynamic type called DynamicFoo which is about as simple of a dynamic class that I can think of:public class DynamicFoo : DynamicObject { Dictionary<string, object> properties = new Dictionary<string, object>(); public string Bar { get; set; } public DateTime Entered { get; set; } public override bool TryGetMember(GetMemberBinder binder, out object result) { result = null; if (!properties.ContainsKey(binder.Name)) return false; result = properties[binder.Name]; return true; } public override bool TrySetMember(SetMemberBinder binder, object value) { properties[binder.Name] = value; return true; } } This class has an internal dictionary member and I'm exposing this dictionary member through a dynamic by implementing DynamicObject. This implementation exposes the properties dictionary so the dictionary keys can be referenced like properties (foo.NewProperty = "Cool!"). I override TryGetMember() and TrySetMember() which are fired at runtime every time you access a 'property' on a dynamic instance of this DynamicFoo type. Strong Typing and Dynamic Casting I now can instantiate and use DynamicFoo in a couple of different ways: Strong TypingDynamicFoo fooExplicit = new DynamicFoo(); var fooVar = new DynamicFoo(); These two commands are essentially identical and use strong typing. The compiler generates identical code for both of them. The var statement is merely a compiler directive to infer the type of fooVar at compile time and so the type of fooExplicit is DynamicFoo, just like fooExplicit. This is very static - nothing dynamic about it - and it completely ignores the IDynamicMetaObjectProvider implementation of my class above as it's never used. Using either of these I can access the native properties:DynamicFoo fooExplicit = new DynamicFoo();// static typing assignmentsfooVar.Bar = "Barred!"; fooExplicit.Entered = DateTime.Now; // echo back static values Console.WriteLine(fooVar.Bar); Console.WriteLine(fooExplicit.Entered); but I have no access whatsoever to the properties dictionary. Basically this creates a strongly typed instance of the type with access only to the strongly typed interface. You get no dynamic behavior at all. The IDynamicMetaObjectProvider features don't kick in until you cast the type to dynamic. If I try to access a non-existing property on fooExplicit I get a compilation error that tells me that the property doesn't exist. Again, it's clearly and utterly non-dynamic. Dynamicdynamic fooDynamic = new DynamicFoo(); fooDynamic on the other hand is created as a dynamic type and it's a completely different beast. I can also create a dynamic by simply casting any type to dynamic like this:DynamicFoo fooExplicit = new DynamicFoo(); dynamic fooDynamic = fooExplicit; Note that dynamic typically doesn't require an explicit cast as the compiler automatically performs the cast so there's no need to use as dynamic. Dynamic functionality works at runtime and allows for the dynamic wrapper to look up and call members dynamically. A dynamic type will look for members to access or call in two places: Using the strongly typed members of the object Using theIDynamicMetaObjectProvider Interface methods to access members So rather than statically linking and calling a method or retrieving a property, the dynamic type looks up - at runtime  - where the value actually comes from. It's essentially late-binding which allows runtime determination what action to take when a member is accessed at runtime *if* the member you are accessing does not exist on the object. Class members are checked first before IDynamicMetaObjectProvider interface methods are kick in. All of the following works with the dynamic type:dynamic fooDynamic = new DynamicFoo(); // dynamic typing assignments fooDynamic.NewProperty = "Something new!"; fooDynamic.LastAccess = DateTime.Now; // dynamic assigning static properties fooDynamic.Bar = "dynamic barred"; fooDynamic.Entered = DateTime.Now; // echo back dynamic values Console.WriteLine(fooDynamic.NewProperty); Console.WriteLine(fooDynamic.LastAccess); Console.WriteLine(fooDynamic.Bar); Console.WriteLine(fooDynamic.Entered); The dynamic type can access the native class properties (Bar and Entered) and create and read new ones (NewProperty,LastAccess) all using a single type instance which is pretty cool. As you can see it's pretty easy to create an extensible type this way that can dynamically add members at runtime dynamically. The Alter Ego of IDynamicObject The key point here is that all three statements - explicit, var and dynamic - declare a new DynamicFoo(), but the dynamic declaration results in completely different behavior than the first two simply because the type has been cast to dynamic. Dynamic binding means that the type loses its typical strong typing, compile time features. You can see this easily in the Visual Studio code editor. As soon as you assign a value to a dynamic you lose Intellisense and you see which means there's no Intellisense and no compiler type checking on any members you apply to this instance. If you're new to the dynamic type it might seem really confusing that a single type can behave differently depending on how it is cast, but that's exactly what happens when you use a type that implements IDynamicMetaObjectProvider. Declare the type as its strong type name and you only get to access the native instance members of the type. Declare or cast it to dynamic and you get dynamic behavior which accesses native members plus it uses IDynamicMetaObjectProvider implementation to handle any missing member definitions by running custom code. You can easily cast objects back and forth between dynamic and the original type:dynamic fooDynamic = new DynamicFoo(); fooDynamic.NewProperty = "New Property Value"; DynamicFoo foo = fooDynamic; foo.Bar = "Barred"; Here the code starts out with a dynamic cast and a dynamic assignment. The code then casts back the value to the DynamicFoo. Notice that when casting from dynamic to DynamicFoo and back we typically do not have to specify the cast explicitly - the compiler can induce the type so I don't need to specify as dynamic or as DynamicFoo. Moral of the Story This easy interchange between dynamic and the underlying type is actually super useful, because it allows you to create extensible objects that can expose non-member data stores and expose them as an object interface. You can create an object that hosts a number of strongly typed properties and then cast the object to dynamic and add additional dynamic properties to the same type at runtime. You can easily switch back and forth between the strongly typed instance to access the well-known strongly typed properties and to dynamic for the dynamic properties added at runtime. Keep in mind that dynamic object access has quite a bit of overhead and is definitely slower than strongly typed binding, so if you're accessing the strongly typed parts of your objects you definitely want to use a strongly typed reference. Reserve dynamic for the dynamic members to optimize your code. The real beauty of dynamic is that with very little effort you can build expandable objects or objects that expose different data stores to an object interface. I'll have more on this in my next post when I create a customized and extensible Expando object based on DynamicObject.© Rick Strahl, West Wind Technologies, 2005-2012Posted in CSharp  .NET   Tweet !function(d,s,id){var js,fjs=d.getElementsByTagName(s)[0];if(!d.getElementById(id)){js=d.createElement(s);js.id=id;js.src="//platform.twitter.com/widgets.js";fjs.parentNode.insertBefore(js,fjs);}}(document,"script","twitter-wjs"); (function() { var po = document.createElement('script'); po.type = 'text/javascript'; po.async = true; po.src = 'https://apis.google.com/js/plusone.js'; var s = document.getElementsByTagName('script')[0]; s.parentNode.insertBefore(po, s); })();

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  • ODI 12c - Parallel Table Load

    - by David Allan
    In this post we will look at the ODI 12c capability of parallel table load from the aspect of the mapping developer and the knowledge module developer - two quite different viewpoints. This is about parallel table loading which isn't to be confused with loading multiple targets per se. It supports the ability for ODI mappings to be executed concurrently especially if there is an overlap of the datastores that they access, so any temporary resources created may be uniquely constructed by ODI. Temporary objects can be anything basically - common examples are staging tables, indexes, views, directories - anything in the ETL to help the data integration flow do its job. In ODI 11g users found a few workarounds (such as changing the technology prefixes - see here) to build unique temporary names but it was more of a challenge in error cases. ODI 12c mappings by default operate exactly as they did in ODI 11g with respect to these temporary names (this is also true for upgraded interfaces and scenarios) but can be configured to support the uniqueness capabilities. We will look at this feature from two aspects; that of a mapping developer and that of a developer (of procedures or KMs). 1. Firstly as a Mapping Developer..... 1.1 Control when uniqueness is enabled A new property is available to set unique name generation on/off. When unique names have been enabled for a mapping, all temporary names used by the collection and integration objects will be generated using unique names. This property is presented as a check-box in the Property Inspector for a deployment specification. 1.2 Handle cleanup after successful execution Provided that all temporary objects that are created have a corresponding drop statement then all of the temporary objects should be removed during a successful execution. This should be the case with the KMs developed by Oracle. 1.3 Handle cleanup after unsuccessful execution If an execution failed in ODI 11g then temporary tables would have been left around and cleaned up in the subsequent run. In ODI 12c, KM tasks can now have a cleanup-type task which is executed even after a failure in the main tasks. These cleanup tasks will be executed even on failure if the property 'Remove Temporary Objects on Error' is set. If the agent was to crash and not be able to execute this task, then there is an ODI tool (OdiRemoveTemporaryObjects here) you can invoke to cleanup the tables - it supports date ranges and the like. That's all there is to it from the aspect of the mapping developer it's much, much simpler and straightforward. You can now execute the same mapping concurrently or execute many mappings using the same resource concurrently without worrying about conflict.  2. Secondly as a Procedure or KM Developer..... In the ODI Operator the executed code shows the actual name that is generated - you can also see the runtime code prior to execution (introduced in 11.1.1.7), for example below in the code type I selected 'Pre-executed Code' this lets you see the code about to be processed and you can also see the executed code (which is the default view). References to the collection (C$) and integration (I$) names will be automatically made unique by using the odiRef APIs - these objects will have unique names whenever concurrency has been enabled for a particular mapping deployment specification. It's also possible to use name uniqueness functions in procedures and your own KMs. 2.1 New uniqueness tags  You can also make your own temporary objects have unique names by explicitly including either %UNIQUE_STEP_TAG or %UNIQUE_SESSION_TAG in the name passed to calls to the odiRef APIs. Such names would always include the unique tag regardless of the concurrency setting. To illustrate, let's look at the getObjectName() method. At <% expansion time, this API will append %UNIQUE_STEP_TAG to the object name for collection and integration tables. The name parameter passed to this API may contain  %UNIQUE_STEP_TAG or %UNIQUE_SESSION_TAG. This API always generates to the <? version of getObjectName() At execution time this API will replace the unique tag macros with a string that is unique to the current execution scope. The returned name will conform to the name-length restriction for the target technology, and its pattern for the unique tag. Any necessary truncation will be performed against the initial name for the object and any other fixed text that may have been specified. Examples are:- <?=odiRef.getObjectName("L", "%COL_PRFEMP%UNIQUE_STEP_TAG", "D")?> SCOTT.C$_EABH7QI1BR1EQI3M76PG9SIMBQQ <?=odiRef.getObjectName("L", "EMP%UNIQUE_STEP_TAG_AE", "D")?> SCOTT.EMPAO96Q2JEKO0FTHQP77TMSAIOSR_ Methods which have this kind of support include getFrom, getTableName, getTable, getObjectShortName and getTemporaryIndex. There are APIs for retrieving this tag info also, the getInfo API has been extended with the following properties (the UNIQUE* properties can also be used in ODI procedures); UNIQUE_STEP_TAG - Returns the unique value for the current step scope, e.g. 5rvmd8hOIy7OU2o1FhsF61 Note that this will be a different value for each loop-iteration when the step is in a loop. UNIQUE_SESSION_TAG - Returns the unique value for the current session scope, e.g. 6N38vXLrgjwUwT5MseHHY9 IS_CONCURRENT - Returns info about the current mapping, will return 0 or 1 (only in % phase) GUID_SRC_SET - Returns the UUID for the current source set/execution unit (only in % phase) The getPop API has been extended with the IS_CONCURRENT property which returns info about an mapping, will return 0 or 1.  2.2 Additional APIs Some new APIs are provided including getFormattedName which will allow KM developers to construct a name from fixed-text or ODI symbols that can be optionally truncate to a max length and use a specific encoding for the unique tag. It has syntax getFormattedName(String pName[, String pTechnologyCode]) This API is available at both the % and the ? phase.  The format string can contain the ODI prefixes that are available for getObjectName(), e.g. %INT_PRF, %COL_PRF, %ERR_PRF, %IDX_PRF alongwith %UNIQUE_STEP_TAG or %UNIQUE_SESSION_TAG. The latter tags will be expanded into a unique string according to the specified technology. Calls to this API within the same execution context are guaranteed to return the same unique name provided that the same parameters are passed to the call. e.g. <%=odiRef.getFormattedName("%COL_PRFMY_TABLE%UNIQUE_STEP_TAG_AE", "ORACLE")%> <?=odiRef.getFormattedName("%COL_PRFMY_TABLE%UNIQUE_STEP_TAG_AE", "ORACLE")?> C$_MY_TAB7wDiBe80vBog1auacS1xB_AE <?=odiRef.getFormattedName("%COL_PRFMY_TABLE%UNIQUE_STEP_TAG.log", "FILE")?> C2_MY_TAB7wDiBe80vBog1auacS1xB.log 2.3 Name length generation  As part of name generation, the length of the generated name will be compared with the maximum length for the target technology and truncation may need to be applied. When a unique tag is included in the generated string it is important that uniqueness is not compromised by truncation of the unique tag. When a unique tag is NOT part of the generated name, the name will be truncated by removing characters from the end - this is the existing 11g algorithm. When a unique tag is included, the algorithm will first truncate the <postfix> and if necessary  the <prefix>. It is recommended that users will ensure there is sufficient uniqueness in the <prefix> section to ensure uniqueness of the final resultant name. SUMMARY To summarize, ODI 12c make it much simpler to utilize mappings in concurrent cases and provides APIs for helping developing any procedures or custom knowledge modules in such a way they can be used in highly concurrent, parallel scenarios. 

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  • How Assassin’s Creed Should Have Ended [Video]

    - by Asian Angel
    Altair is on the run yet again from Italy’s finest and keeps managing to hide in plain sight. But will his luck hold out or will his final attempt to escape end in tragedy? How It Should Have Ended: Video…: Assassin’s Creed [via Dorkly Bits] How To Properly Scan a Photograph (And Get An Even Better Image) The HTG Guide to Hiding Your Data in a TrueCrypt Hidden Volume Make Your Own Windows 8 Start Button with Zero Memory Usage

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  • Laser Cutter Plays Portal Theme Song While Cutting Aperture Science Logo [Video]

    - by Jason Fitzpatrick
    We’re at a total loss to think of anything more geeky than a laser cutter programmed to simultaneously laser cut the Aperture Science logo while playing “Stile Alive” from Portal. If you’re unfamiliar with the original tune, check out this video. [via Boing Boing] The HTG Guide to Hiding Your Data in a TrueCrypt Hidden Volume Make Your Own Windows 8 Start Button with Zero Memory Usage Reader Request: How To Repair Blurry Photos

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  • Cracking open five of the best open source easter eggs

    <b>ars Technica:</b> "A number of humorous yet undocumented features are hiding beneath the surface of some of the most popular open source software applications. Although easter eggs are generally easy to spot when you can look at an application's source code, there are a few that aren't widely known."

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  • Analyzing the errorlog

    - by TiborKaraszi
    How often do you do this? Look over each message (type) in the errorlog file and determine whether this is something you want to act on. Sure, some (but not all) of you have some monitoring solution in place, but are you 100% confident that it really will notify for all messages that you might find interesting? That there isn't even one little message hiding in there that you would find valuable knowing about? Or how about messages that you typically don't are about, but knowing that you have a high...(read more)

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  • Make Your Desktop an Aquarian Paradise with the Blue Water Theme for Windows 7

    - by Asian Angel
    Do you enjoy being near bodies of water regardless of type? Then you will definitely want to grab a copy of the Blue Water Theme for Windows 7. This terrific theme comes with ten images featuring streams, lakes, rivers, and the ocean that quickly turn your desktop into a perfect aquarian paradise. Download the Blue Water Theme [Windows 7 Personalization Gallery] How To Be Your Own Personal Clone Army (With a Little Photoshop) How To Properly Scan a Photograph (And Get An Even Better Image) The HTG Guide to Hiding Your Data in a TrueCrypt Hidden Volume

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  • If Computer Problems were Physical Life Events [Video]

    - by Asian Angel
    Things can be bad (and frustrating) enough when you have problems with your computer, but what if those events actually crossed over into physical reality? Note: Video contains some language that may be considered inappropriate. If Computer Problems Were Real – Awkward Spaceship [via Fail Desk] How To Properly Scan a Photograph (And Get An Even Better Image) The HTG Guide to Hiding Your Data in a TrueCrypt Hidden Volume Make Your Own Windows 8 Start Button with Zero Memory Usage

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  • From the Tips Box: Telescope Laser Sights, Drobox Desktops, and Kindle Clipping Conversions

    - by Jason Fitzpatrick
    Once a week we round up some great reader tips and share them with everyone; this week we’re looking at telescope laser sights, syncing your desktop with Dropbox, and converting your Kindle Clippings file. How To Properly Scan a Photograph (And Get An Even Better Image) The HTG Guide to Hiding Your Data in a TrueCrypt Hidden Volume Make Your Own Windows 8 Start Button with Zero Memory Usage

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