struct vs class - Page 341

How to retrieve CSS style object by CSS class name?

- by Chir

Hi, Is it possible to get all properties of a css class associated with an element? e.g. .hightligh { font-weight: bold; border: 1px solid red; padding-top:10px; } Lets say the css class "hightlight" is assigned to div element <div class='highlight'></div> Now using JavaScript, I need to iterate through all style properties of css class "highlight" associated with the div element. Basically, I want to treat it as a JavaScript object whose properties can be accessed using iterator or for loop. Thanks in advance

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Make error when compiling Perl 5.12.1 (RHEL 5.5)

- by ascent1729

I am trying to compile Perl 5.12.1 in my home directory on Red Hat Enterprise Linux 5.5. However, when I try to make, I eventually receive the following error: Making IO (all) make[1]: Entering directory `/users/rmi1/build/perl-5.12.0/dist/IO' make[1]: Leaving directory `/users/rmi1/build/perl-5.12.0/dist/IO' Making all in dist/IO make all PERL_CORE=1 LIBPERL_A=libperl.a LINKTYPE=dynamic make[1]: Entering directory `/users/rmi1/build/perl-5.12.0/dist/IO' cc -c -fno-strict-aliasing -pipe -fstack-protector -I/usr/local/include -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -O2 -DVERSION=\"1.25_02\" -DXS_VERSION=\"1.25_02\" -fPIC "-I../.." IO.c IO.xs: In function ‘XS_IO__Poll__poll’: IO.xs:249: error: invalid application of ‘sizeof’ to incomplete type ‘struct pollfd’ IO.xs:253: error: invalid use of undefined type ‘struct pollfd’ IO.xs:253: error: dereferencing pointer to incomplete type IO.xs:255: error: invalid use of undefined type ‘struct pollfd’ IO.xs:255: error: dereferencing pointer to incomplete type IO.xs:257: error: invalid use of undefined type ‘struct pollfd’ IO.xs:257: error: dereferencing pointer to incomplete type IO.xs:261: error: invalid use of undefined type ‘struct pollfd’ IO.xs:261: error: dereferencing pointer to incomplete type IO.xs:262: error: invalid use of undefined type ‘struct pollfd’ IO.xs:262: error: dereferencing pointer to incomplete type make[1]: *** [IO.o] Error 1 make[1]: Leaving directory `/users/rmi1/build/perl-5.12.0/dist/IO' Unsuccessful make(dist/IO): code=512 at make_ext.pl line 449. make: *** [lib/auto/IO/IO.so] Error 2 What could be causing this?

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Inheritance Mapping Strategies with Entity Framework Code First CTP5 Part 1: Table per Hierarchy (TPH)

- by mortezam

A simple strategy for mapping classes to database tables might be “one table for every entity persistent class.” This approach sounds simple enough and, indeed, works well until we encounter inheritance. Inheritance is such a visible structural mismatch between the object-oriented and relational worlds because object-oriented systems model both “is a” and “has a” relationships. SQL-based models provide only "has a" relationships between entities; SQL database management systems don’t support type inheritance—and even when it’s available, it’s usually proprietary or incomplete. There are three different approaches to representing an inheritance hierarchy: Table per Hierarchy (TPH): Enable polymorphism by denormalizing the SQL schema, and utilize a type discriminator column that holds type information. Table per Type (TPT): Represent "is a" (inheritance) relationships as "has a" (foreign key) relationships. Table per Concrete class (TPC): Discard polymorphism and inheritance relationships completely from the SQL schema.I will explain each of these strategies in a series of posts and this one is dedicated to TPH. In this series we'll deeply dig into each of these strategies and will learn about "why" to choose them as well as "how" to implement them. Hopefully it will give you a better idea about which strategy to choose in a particular scenario. Inheritance Mapping with Entity Framework Code FirstAll of the inheritance mapping strategies that we discuss in this series will be implemented by EF Code First CTP5. The CTP5 build of the new EF Code First library has been released by ADO.NET team earlier this month. EF Code-First enables a pretty powerful code-centric development workflow for working with data. I’m a big fan of the EF Code First approach, and I’m pretty excited about a lot of productivity and power that it brings. When it comes to inheritance mapping, not only Code First fully supports all the strategies but also gives you ultimate flexibility to work with domain models that involves inheritance. The fluent API for inheritance mapping in CTP5 has been improved a lot and now it's more intuitive and concise in compare to CTP4. A Note For Those Who Follow Other Entity Framework ApproachesIf you are following EF's "Database First" or "Model First" approaches, I still recommend to read this series since although the implementation is Code First specific but the explanations around each of the strategies is perfectly applied to all approaches be it Code First or others. A Note For Those Who are New to Entity Framework and Code-FirstIf you choose to learn EF you've chosen well. If you choose to learn EF with Code First you've done even better. To get started, you can find a great walkthrough by Scott Guthrie here and another one by ADO.NET team here. In this post, I assume you already setup your machine to do Code First development and also that you are familiar with Code First fundamentals and basic concepts. You might also want to check out my other posts on EF Code First like Complex Types and Shared Primary Key Associations. A Top Down Development ScenarioThese posts take a top-down approach; it assumes that you’re starting with a domain model and trying to derive a new SQL schema. Therefore, we start with an existing domain model, implement it in C# and then let Code First create the database schema for us. However, the mapping strategies described are just as relevant if you’re working bottom up, starting with existing database tables. I’ll show some tricks along the way that help you dealing with nonperfect table layouts. Let’s start with the mapping of entity inheritance. -- The Domain ModelIn our domain model, we have a BillingDetail base class which is abstract (note the italic font on the UML class diagram below). We do allow various billing types and represent them as subclasses of BillingDetail class. As for now, we support CreditCard and BankAccount: Implement the Object Model with Code First As always, we start with the POCO classes. Note that in our DbContext, I only define one DbSet for the base class which is BillingDetail. Code First will find the other classes in the hierarchy based on Reachability Convention. public abstract class BillingDetail { public int BillingDetailId { get; set; } public string Owner { get; set; } public string Number { get; set; } } public class BankAccount : BillingDetail { public string BankName { get; set; } public string Swift { get; set; } } public class CreditCard : BillingDetail { public int CardType { get; set; } public string ExpiryMonth { get; set; } public string ExpiryYear { get; set; } } public class InheritanceMappingContext : DbContext { public DbSet<BillingDetail> BillingDetails { get; set; } } This object model is all that is needed to enable inheritance with Code First. If you put this in your application you would be able to immediately start working with the database and do CRUD operations. Before going into details about how EF Code First maps this object model to the database, we need to learn about one of the core concepts of inheritance mapping: polymorphic and non-polymorphic queries. Polymorphic Queries LINQ to Entities and EntitySQL, as object-oriented query languages, both support polymorphic queries—that is, queries for instances of a class and all instances of its subclasses, respectively. For example, consider the following query: IQueryable<BillingDetail> linqQuery = from b in context.BillingDetails select b; List<BillingDetail> billingDetails = linqQuery.ToList(); Or the same query in EntitySQL: string eSqlQuery = @"SELECT VAlUE b FROM BillingDetails AS b"; ObjectQuery<BillingDetail> objectQuery = ((IObjectContextAdapter)context).ObjectContext .CreateQuery<BillingDetail>(eSqlQuery); List<BillingDetail> billingDetails = objectQuery.ToList(); linqQuery and eSqlQuery are both polymorphic and return a list of objects of the type BillingDetail, which is an abstract class but the actual concrete objects in the list are of the subtypes of BillingDetail: CreditCard and BankAccount. Non-polymorphic QueriesAll LINQ to Entities and EntitySQL queries are polymorphic which return not only instances of the specific entity class to which it refers, but all subclasses of that class as well. On the other hand, Non-polymorphic queries are queries whose polymorphism is restricted and only returns instances of a particular subclass. In LINQ to Entities, this can be specified by using OfType<T>() Method. For example, the following query returns only instances of BankAccount: IQueryable<BankAccount> query = from b in context.BillingDetails.OfType<BankAccount>() select b; EntitySQL has OFTYPE operator that does the same thing: string eSqlQuery = @"SELECT VAlUE b FROM OFTYPE(BillingDetails, Model.BankAccount) AS b"; In fact, the above query with OFTYPE operator is a short form of the following query expression that uses TREAT and IS OF operators: string eSqlQuery = @"SELECT VAlUE TREAT(b as Model.BankAccount) FROM BillingDetails AS b WHERE b IS OF(Model.BankAccount)"; (Note that in the above query, Model.BankAccount is the fully qualified name for BankAccount class. You need to change "Model" with your own namespace name.) Table per Class Hierarchy (TPH)An entire class hierarchy can be mapped to a single table. This table includes columns for all properties of all classes in the hierarchy. The concrete subclass represented by a particular row is identified by the value of a type discriminator column. You don’t have to do anything special in Code First to enable TPH. It's the default inheritance mapping strategy: This mapping strategy is a winner in terms of both performance and simplicity. It’s the best-performing way to represent polymorphism—both polymorphic and nonpolymorphic queries perform well—and it’s even easy to implement by hand. Ad-hoc reporting is possible without complex joins or unions. Schema evolution is straightforward. Discriminator Column As you can see in the DB schema above, Code First has to add a special column to distinguish between persistent classes: the discriminator. This isn’t a property of the persistent class in our object model; it’s used internally by EF Code First. By default, the column name is "Discriminator", and its type is string. The values defaults to the persistent class names —in this case, “BankAccount” or “CreditCard”. EF Code First automatically sets and retrieves the discriminator values. TPH Requires Properties in SubClasses to be Nullable in the Database TPH has one major problem: Columns for properties declared by subclasses will be nullable in the database. For example, Code First created an (INT, NULL) column to map CardType property in CreditCard class. However, in a typical mapping scenario, Code First always creates an (INT, NOT NULL) column in the database for an int property in persistent class. But in this case, since BankAccount instance won’t have a CardType property, the CardType field must be NULL for that row so Code First creates an (INT, NULL) instead. If your subclasses each define several non-nullable properties, the loss of NOT NULL constraints may be a serious problem from the point of view of data integrity. TPH Violates the Third Normal FormAnother important issue is normalization. We’ve created functional dependencies between nonkey columns, violating the third normal form. Basically, the value of Discriminator column determines the corresponding values of the columns that belong to the subclasses (e.g. BankName) but Discriminator is not part of the primary key for the table. As always, denormalization for performance can be misleading, because it sacrifices long-term stability, maintainability, and the integrity of data for immediate gains that may be also achieved by proper optimization of the SQL execution plans (in other words, ask your DBA). Generated SQL QueryLet's take a look at the SQL statements that EF Code First sends to the database when we write queries in LINQ to Entities or EntitySQL. For example, the polymorphic query for BillingDetails that you saw, generates the following SQL statement: SELECT [Extent1].[Discriminator] AS [Discriminator], [Extent1].[BillingDetailId] AS [BillingDetailId], [Extent1].[Owner] AS [Owner], [Extent1].[Number] AS [Number], [Extent1].[BankName] AS [BankName], [Extent1].[Swift] AS [Swift], [Extent1].[CardType] AS [CardType], [Extent1].[ExpiryMonth] AS [ExpiryMonth], [Extent1].[ExpiryYear] AS [ExpiryYear] FROM [dbo].[BillingDetails] AS [Extent1] WHERE [Extent1].[Discriminator] IN ('BankAccount','CreditCard') Or the non-polymorphic query for the BankAccount subclass generates this SQL statement: SELECT [Extent1].[BillingDetailId] AS [BillingDetailId], [Extent1].[Owner] AS [Owner], [Extent1].[Number] AS [Number], [Extent1].[BankName] AS [BankName], [Extent1].[Swift] AS [Swift] FROM [dbo].[BillingDetails] AS [Extent1] WHERE [Extent1].[Discriminator] = 'BankAccount' Note how Code First adds a restriction on the discriminator column and also how it only selects those columns that belong to BankAccount entity. Change Discriminator Column Data Type and Values With Fluent API Sometimes, especially in legacy schemas, you need to override the conventions for the discriminator column so that Code First can work with the schema. The following fluent API code will change the discriminator column name to "BillingDetailType" and the values to "BA" and "CC" for BankAccount and CreditCard respectively: protected override void OnModelCreating(System.Data.Entity.ModelConfiguration.ModelBuilder modelBuilder) { modelBuilder.Entity<BillingDetail>() .Map<BankAccount>(m => m.Requires("BillingDetailType").HasValue("BA")) .Map<CreditCard>(m => m.Requires("BillingDetailType").HasValue("CC")); } Also, changing the data type of discriminator column is interesting. In the above code, we passed strings to HasValue method but this method has been defined to accepts a type of object: public void HasValue(object value); Therefore, if for example we pass a value of type int to it then Code First not only use our desired values (i.e. 1 & 2) in the discriminator column but also changes the column type to be (INT, NOT NULL): modelBuilder.Entity<BillingDetail>() .Map<BankAccount>(m => m.Requires("BillingDetailType").HasValue(1)) .Map<CreditCard>(m => m.Requires("BillingDetailType").HasValue(2)); SummaryIn this post we learned about Table per Hierarchy as the default mapping strategy in Code First. The disadvantages of the TPH strategy may be too serious for your design—after all, denormalized schemas can become a major burden in the long run. Your DBA may not like it at all. In the next post, we will learn about Table per Type (TPT) strategy that doesn’t expose you to this problem. References ADO.NET team blog Java Persistence with Hibernate book a { text-decoration: none; } a:visited { color: Blue; } .title { padding-bottom: 5px; font-family: Segoe UI; font-size: 11pt; font-weight: bold; padding-top: 15px; } .code, .typeName { font-family: consolas; } .typeName { color: #2b91af; } .padTop5 { padding-top: 5px; } .padTop10 { padding-top: 10px; } p.MsoNormal { margin-top: 0in; margin-right: 0in; margin-bottom: 10.0pt; margin-left: 0in; line-height: 115%; font-size: 11.0pt; font-family: "Calibri" , "sans-serif"; }

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Silverlight Tree View with Multiple Levels

- by psheriff

There are many examples of the Silverlight Tree View that you will find on the web, however, most of them only show you how to go to two levels. What if you have more than two levels? This is where understanding exactly how the Hierarchical Data Templates works is vital. In this blog post, I am going to break down how these templates work so you can really understand what is going on underneath the hood. To start, let’s look at the typical two-level Silverlight Tree View that has been hard coded with the values shown below: <sdk:TreeView> <sdk:TreeViewItem Header="Managers"> <TextBlock Text="Michael" /> <TextBlock Text="Paul" /> </sdk:TreeViewItem> <sdk:TreeViewItem Header="Supervisors"> <TextBlock Text="John" /> <TextBlock Text="Tim" /> <TextBlock Text="David" /> </sdk:TreeViewItem></sdk:TreeView> Figure 1 shows you how this tree view looks when you run the Silverlight application. Figure 1: A hard-coded, two level Tree View. Next, let’s create three classes to mimic the hard-coded Tree View shown above. First, you need an Employee class and an EmployeeType class. The Employee class simply has one property called Name. The constructor is created to accept a “name” argument that you can use to set the Name property when you create an Employee object. public class Employee{ public Employee(string name) { Name = name; } public string Name { get; set; }} Finally you create an EmployeeType class. This class has one property called EmpType and contains a generic List<> collection of Employee objects. The property that holds the collection is called Employees. public class EmployeeType{ public EmployeeType(string empType) { EmpType = empType; Employees = new List<Employee>(); } public string EmpType { get; set; } public List<Employee> Employees { get; set; }} Finally we have a collection class called EmployeeTypes created using the generic List<> class. It is in the constructor for this class where you will build the collection of EmployeeTypes and fill it with Employee objects: public class EmployeeTypes : List<EmployeeType>{ public EmployeeTypes() { EmployeeType type; type = new EmployeeType("Manager"); type.Employees.Add(new Employee("Michael")); type.Employees.Add(new Employee("Paul")); this.Add(type); type = new EmployeeType("Project Managers"); type.Employees.Add(new Employee("Tim")); type.Employees.Add(new Employee("John")); type.Employees.Add(new Employee("David")); this.Add(type); }} You now have a data hierarchy in memory (Figure 2) which is what the Tree View control expects to receive as its data source. Figure 2: A hierachial data structure of Employee Types containing a collection of Employee objects. To connect up this hierarchy of data to your Tree View you create an instance of the EmployeeTypes class in XAML as shown in line 13 of Figure 3. The key assigned to this object is “empTypes”. This key is used as the source of data to the entire Tree View by setting the ItemsSource property as shown in Figure 3, Callout #1. Figure 3: You need to start from the bottom up when laying out your templates for a Tree View. The ItemsSource property of the Tree View control is used as the data source in the Hierarchical Data Template with the key of employeeTypeTemplate. In this case there is only one Hierarchical Data Template, so any data you wish to display within that template comes from the collection of Employee Types. The TextBlock control in line 20 uses the EmpType property of the EmployeeType class. You specify the name of the Hierarchical Data Template to use in the ItemTemplate property of the Tree View (Callout #2). For the second (and last) level of the Tree View control you use a normal <DataTemplate> with the name of employeeTemplate (line 14). The Hierarchical Data Template in lines 17-21 sets its ItemTemplate property to the key name of employeeTemplate (Line 19 connects to Line 14). The source of the data for the <DataTemplate> needs to be a property of the EmployeeTypes collection used in the Hierarchical Data Template. In this case that is the Employees property. In the Employees property there is a “Name” property of the Employee class that is used to display the employee name in the second level of the Tree View (Line 15). What is important here is that your lowest level in your Tree View is expressed in a <DataTemplate> and should be listed first in your Resources section. The next level up in your Tree View should be a <HierarchicalDataTemplate> which has its ItemTemplate property set to the key name of the <DataTemplate> and the ItemsSource property set to the data you wish to display in the <DataTemplate>. The Tree View control should have its ItemsSource property set to the data you wish to display in the <HierarchicalDataTemplate> and its ItemTemplate property set to the key name of the <HierarchicalDataTemplate> object. It is in this way that you get the Tree View to display all levels of your hierarchical data structure. Three Levels in a Tree View Now let’s expand upon this concept and use three levels in our Tree View (Figure 4). This Tree View shows that you now have EmployeeTypes at the top of the tree, followed by a small set of employees that themselves manage employees. This means that the EmployeeType class has a collection of Employee objects. Each Employee class has a collection of Employee objects as well. Figure 4: When using 3 levels in your TreeView you will have 2 Hierarchical Data Templates and 1 Data Template. The EmployeeType class has not changed at all from our previous example. However, the Employee class now has one additional property as shown below: public class Employee{ public Employee(string name) { Name = name; ManagedEmployees = new List<Employee>(); } public string Name { get; set; } public List<Employee> ManagedEmployees { get; set; }} The next thing that changes in our code is the EmployeeTypes class. The constructor now needs additional code to create a list of managed employees. Below is the new code. public class EmployeeTypes : List<EmployeeType>{ public EmployeeTypes() { EmployeeType type; Employee emp; Employee managed; type = new EmployeeType("Manager"); emp = new Employee("Michael"); managed = new Employee("John"); emp.ManagedEmployees.Add(managed); managed = new Employee("Tim"); emp.ManagedEmployees.Add(managed); type.Employees.Add(emp); emp = new Employee("Paul"); managed = new Employee("Michael"); emp.ManagedEmployees.Add(managed); managed = new Employee("Sara"); emp.ManagedEmployees.Add(managed); type.Employees.Add(emp); this.Add(type); type = new EmployeeType("Project Managers"); type.Employees.Add(new Employee("Tim")); type.Employees.Add(new Employee("John")); type.Employees.Add(new Employee("David")); this.Add(type); }} Now that you have all of the data built in your classes, you are now ready to hook up this three-level structure to your Tree View. Figure 5 shows the complete XAML needed to hook up your three-level Tree View. You can see in the XAML that there are now two Hierarchical Data Templates and one Data Template. Again you list the Data Template first since that is the lowest level in your Tree View. The next Hierarchical Data Template listed is the next level up from the lowest level, and finally you have a Hierarchical Data Template for the first level in your tree. You need to work your way from the bottom up when creating your Tree View hierarchy. XAML is processed from the top down, so if you attempt to reference a XAML key name that is below where you are referencing it from, you will get a runtime error. Figure 5: For three levels in a Tree View you will need two Hierarchical Data Templates and one Data Template. Each Hierarchical Data Template uses the previous template as its ItemTemplate. The ItemsSource of each Hierarchical Data Template is used to feed the data to the previous template. This is probably the most confusing part about working with the Tree View control. You are expecting the content of the current Hierarchical Data Template to use the properties set in the ItemsSource property of that template. But you need to look to the template lower down in the XAML to see the source of the data as shown in Figure 6. Figure 6: The properties you use within the Content of a template come from the ItemsSource of the next template in the resources section. Summary Understanding how to put together your hierarchy in a Tree View is simple once you understand that you need to work from the bottom up. Start with the bottom node in your Tree View and determine what that will look like and where the data will come from. You then build the next Hierarchical Data Template to feed the data to the previous template you created. You keep doing this for each level in your Tree View until you get to the last level. The data for that last Hierarchical Data Template comes from the ItemsSource in the Tree View itself. NOTE: You can download the sample code for this article by visiting my website at http://www.pdsa.com/downloads. Select “Tips & Tricks”, then select “Silverlight TreeView with Multiple Levels” from the drop down list.

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VS 2012 Code Review – Before Check In OR After Check In?

- by Tarun Arora

“Is Code Review Important and Effective?” There is a consensus across the industry that code review is an effective and practical way to collar code inconsistency and possible defects early in the software development life cycle. Among others some of the advantages of code reviews are, Bugs are found faster Forces developers to write readable code (code that can be read without explanation or introduction!) Optimization methods/tricks/productive programs spread faster Programmers as specialists "evolve" faster It's fun “Code review is systematic examination (often known as peer review) of computer source code. It is intended to find and fix mistakes overlooked in the initial development phase, improving both the overall quality of software and the developers' skills. Reviews are done in various forms such as pair programming, informal walkthroughs, and formal inspections.” Wikipedia No where does the definition mention whether its better to review code before the code has been committed to version control or after the commit has been performed. No matter which side you favour, Visual Studio 2012 allows you to request for a code review both before check in and also request for a review after check in. Let’s weigh the pros and cons of the approaches independently. Code Review Before Check In or Code Review After Check In? Approach 1 – Code Review before Check in Developer completes the code and feels the code quality is appropriate for check in to TFS. The developer raises a code review request to have a second pair of eyes validate if the code abides to the recommended best practices, will not result in any defects due to common coding mistakes and whether any optimizations can be made to improve the code quality. Image 1 – code review before check in Pros Everything that gets committed to source control is reviewed. Minimizes the chances of smelly code making its way into the code base. Decreases the cost of fixing bugs, remember, the earlier you find them, the lesser the pain in fixing them. Cons Development Code Freeze – Since the changes aren’t in the source control yet. Further development can only be done off-line. The changes have not been through a CI build, hard to say whether the code abides to all build quality standards. Inconsistent! Cumbersome to track the actual code review process. Not every change to the code base is worth reviewing, a lot of effort is invested for very little gain. Approach 2 – Code Review after Check in Developer checks in, random code reviews are performed on the checked in code. Image 2 – Code review after check in Pros The code has already passed the CI build and run through any code analysis plug ins you may have running on the build server. Instruct the developer to ensure ZERO fx cop, style cop and static code analysis before check in. Code is cleaner and smell free even before the code review. No Offline development, developers can continue to develop against the source control. Cons Bad code can easily make its way into the code base. Since the review take place much later in the cycle, the cost of fixing issues can prove to be much higher. Approach 3 – Hybrid Approach The community advocates a more hybrid approach, a blend of tooling and human accountability quotient. Image 3 – Hybrid Approach 1. Code review high impact check ins. It is not possible to review everything, by setting up code review check in policies you can end up slowing your team. More over, the code that you are reviewing before check in hasn't even been through a green CI build either. 2. Tooling. Let the tooling work for you. By running static analysis, fx cop, style cop and other plug ins on the build agent, you can identify the real issues that in my opinion can't possibly be identified using human reviews. Configure the tooling to report back top 10 issues every day. Mandate the manual code review of individuals who keep making it to this list of shame more often. 3. During Merge. I would prefer eliminating some of the other code issues during merge from Main branch to the release branch. In a scrum project this is still easier because cheery picking the merges is a possibility and the size of code being reviewed is still limited. Let the tooling work for you, if some one breaks the CI build often, put them on a gated check in build course until you see improvement. If some one appears on the top 10 list of shame generated via the build then ensure that all their code is reviewed till you see improvement. At the end of the day, the goal is to ensure that the code being delivered is top quality. By enforcing a code review before any check in, you force the developer to work offline or stay put till the review is complete. What do the experts say? So I asked a few expects what they thought of “Code Review quality gate before Checking in code?" Terje Sandstrom | Microsoft ALM MVP You mean a review quality gate BEFORE checking in code????? That would mean a lot of code staying either local or in shelvesets, and not even been through a CI build, and a green CI build being the main criteria for going further, f.e. to the review state. I would not like code laying around with no checkin’s. Having a requirement that code is checked in small pieces, 4-8 hours work max, and AT LEAST daily checkins, a manual code review comes second down the lane. I would expect review quality gates to happen before merging back to main, or before merging to release. But that would all be on checked-in code. Branching is absolutely one way to ease the pain. Another way we are using is automatic quality builds, running metrics, coverage, static code analysis. Unfortunately it takes some time, would be great to be on CI’s – but…., so it’s done scheduled every night. Based on this we get, among other stuff, top 10 lists of suspicious code, which is then subjected to reviews. If a person seems to be very popular on these top 10 lists, we subject every check in from that person to a review for a period. That normally helps. None of the clients I have can afford to have every checkin reviewed, so we need to find ways around it. I don’t disagree with the nicety of having all the code reviewed, but I find it hard to find those resources in today’s enterprises. David V. Corbin | Visual Studio ALM Ranger I tend to agree with both sides. I hate having code that is not checked in, but at the same time hate having “bad” code in the repository. I have found that branching is one approach to solving this dilemma. Code is checked into the private/feature branch before the review, but is not merged over to the “official” branch until after the review. I advocate both, depending on circumstance (especially team dynamics) - The “pre-checkin” is usually for elements that may impact the project as a whole. Think of it as another “gate” along with passing unit tests. - The “post-checkin” may very well not be at the changeset level, but correlates to a review at the “user story” level. Again, this depends on team dynamics in play…. Robert MacLean | Microsoft ALM MVP I do not think there is no right answer for the industry as a whole. In short the question is why do you do reviews? Your question implies risk mitigation, so in low risk areas you can get away with it after check in while in high risk you need to do it before check in. An example is those new to a team or juniors need it much earlier (maybe that is before checkin, maybe that is soon after) than seniors who have shipped twenty sprints on the team. Abhimanyu Singhal | Visual Studio ALM Ranger Depends on per scenario basis. We recommend post check-in reviews when: 1. We don't want to block other checks and processes on manual code reviews. Manual reviews take time, and some pieces may not require manual reviews at all. 2. We need to trace all changes and track history. 3. We have a code promotion strategy/process in place. For risk mitigation, post checkin code can be promoted to Accepted branches. Or can be rejected. Pre Checkin Reviews are used when 1. There is a high risk factor associated 2. Reviewers are generally (most of times) have immediate availability. 3. Team does not have strict tracking needs. Simply speaking, no single process fits all scenarios. You need to select what works best for your team/project. Thomas Schissler | Visual Studio ALM Ranger This is an interesting discussion, I’m right now discussing details about executing code reviews with my teams. I see and understand the aspects you brought in, but there is another side as well, I’d like to point out. 1.) If you do reviews per check in this is not very practical as a hard rule because this will disturb the flow of the team very often or it will lead to reduce the checkin frequency of the devs which I would not accept. 2.) If you do later reviews, for example if you review PBIs, it is not easy to find out which code you should review. Either you review all changesets associate with the PBI, but then you might review code which has been changed with a later checkin and the dev maybe has already fixed the issue. Or you review the diff of the latest changeset of the PBI with the first but then you might also review changes of other PBIs. Jakob Leander | Sr. Director, Avanade In my experience, manual code review: 1. Does not get done and at the very least does not get redone after changes (regardless of intentions at start of project) 2. When a project actually do it, they often do not do it right away = errors pile up 3. Requires a lot of time discussing/defining the standard and for the team to learn it However code review is very important since e.g. even small memory leaks in a high volume web solution have big consequences In the last years I have advocated following approach for code review - Architects up front do “at least one best practice example” of each type of component and tell the team. Copy from this one. This should include error handling, logging, security etc. - Dev lead on project continuously browse code to validate that the best practices are used. Especially that patterns etc. are not broken. You can do this formally after each sprint/iteration if you want. Once this is validated it is unlikely to “go bad” even during later code changes Agree with customer to rely on static code analysis from Visual Studio as the one and only coding standard. This has HUUGE benefits - You can easily tweak to reach the level you desire together with customer - It is easy to measure for both developers/management - It is 100% consistent across code base - It gets validated all the time so you never end up getting hammered by a customer review in the end - It is easy to tell the developer that you do not want code back unless it has zero errors = minimize communication You need to track this at least during nightly builds and make sure team sees total # issues. Do not allow #issues it to grow uncontrolled. On the project I run I require code analysis to have run on code before checkin (checkin rule). This means - You have to have clean compile (or CA wont run) so this is extra benefit = very few broken builds - You can change a few of the rules to compile as errors instead of warnings. I often do this for “missing dispose” issues which you REALLY do not want in your app Tip: Place your custom CA rules files as part of solution. That way it works when you do branching etc. (path to CA file is relative in VS) Some may argue that CA is not as good as manual inspection. But since manual inspection in reality suffers from the 3 issues in start it is IMO a MUCH better (and much cheaper) approach from helicopter perspective Tirthankar Dutta | Director, Avanade I think code review should be run both before and after check ins. There are some code metrics that are meant to be run on the entire codebase … Also, especially on multi-site projects, one should strive to architect in a way that lets men manage the framework while boys write the repetitive code… scales very well with the need to review less by containment and imposing architectural restrictions to emphasise the design. Bruno Capuano | Microsoft ALM MVP For code reviews (means peer reviews) in distributed team I use http://www.vsanywhere.com/default.aspx David Jobling | Global Sr. Director, Avanade Peer review is the only way to scale and its a great practice for all in the team to learn to perform and accept. In my experience you soon learn who's code to watch more than others and tune the attention. Mikkel Toudal Kristiansen | Manager, Avanade If you have several branches in your code base, you will need to merge often. This requires manual merging, when a file has been changed in both branches. It offers a good opportunity to actually review to changed code. So my advice is: Merging between branches should be done as often as possible, it should be done by a senior developer, and he/she should perform a full code review of the code being merged. As for detecting architectural smells and code smells creeping into the code base, one really good third party tools exist: Ndepend (http://www.ndepend.com/, for static code analysis of the current state of the code base). You could also consider adding StyleCop to the solution. Jesse Houwing | Visual Studio ALM Ranger I gave a presentation on this subject on the TechDays conference in NL last year. See my presentation and slides here (talk in Dutch, but English presentation): http://blog.jessehouwing.nl/2012/03/did-you-miss-my-techdaysnl-talk-on-code.html I’d like to add a few more points: - Before/After checking is mostly a trust issue. If you have a team that does diligent peer reviews and regularly talk/sit together or peer review, there’s no need to enforce a before-checkin policy. The peer peer-programming and regular feedback during development can take care of most of the review requirements as long as the team isn’t under stress. - Under stress, enforce pre-checkin reviews, it might sound strange, if you’re already under time or budgetary constraints, but it is under such conditions most real issues start to be created or pile up. - Use tools to catch most common errors, Code Analysis/FxCop was already mentioned. HP Fortify, Resharper, Coderush etc can help you there. There are also a lot of 3rd party rules you can add to Code Analysis. I’ve written a few myself (http://fccopcontrib.codeplex.com) and various teams from Microsoft have added their own rules (MSOCAF for SharePoint, WSSF for WCF). For common errors that keep cropping up, see if you can define a rule. It’s much easier. But more importantly make sure you have a good help page explaining *WHY* it's wrong. If you have small feature or developer branches/shelvesets, you might want to review pre-merge. It’s still better to do peer reviews and peer programming, but the most important thing is that bad quality code doesn’t make it into the important branch. So my philosophy: - Use tooling as much as possible. - Make sure the team understands the tooling and the importance of the things it flags. It’s too easy to just click suppress all to ignore the warnings. - Under stress, tighten process, it’s under stress that the problems of late reviews will really surface - Most importantly if you do reviews do them as early as possible, but never later than needed. In other words, pre-checkin/post checking doesn’t really matter, as long as the review is done before the code is released. It’ll just be much more expensive to fix any review outcomes the later you find them. --- I would love to hear what you think!

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A way to return multiple return values from a method: put method inside class representing return value. Is it a good design?

- by john smith optional

I need to return 2 values from a method. My approach is as follows: create an inner class with 2 fields that will be used to keep those 2 values put the method inside that class instantiate the class and call the method. The only thing that will be changed in the method is that in the end it will assign those 2 values to the fields of the instance. Then I can address those values by referencing to the fields of that object. Is it a good design and why?

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How to get my list of rows from database to show while using Zend-Paginator

- by Matto

I'm fairly new to the world of Zend-Framework, and have taken over a site that is in zend-framework. There is a bug on one of the pages right now and I can not figure it out. I think it has something to do with Zend Paginator, but not sure. This is the code in the controller for the section I am having a problem with: $currentPage = $this->_getParam('page'); $numWebsitesFullOnline = $websites->getWebsitesFullOnline(); $select = $websites->select(); $select->setIntegrityCheck(false); $select->from(array('w' => 'websites'), array('id', 'online', 'kw_adjective', 'kw_name', 'kw_location', 'url', 'email', 'address', 'ftp_server', 'ftp_username', 'ftp_password', 'ftp_folder', 'phone_number', 'indexed', 'youtube_position', 'twitter_user', 'facebook_id', 'video_made', 'image1_id', 'image2_id', 'image3_id', 'bg_color', 'dark_color', 'light_color', 'links_color', 'text_color', 'google_account', 'ganalytics', 'gmaps_status', 'google_position', 'gmap_position', 'hp1', 'hp2', 'hp3', 'hp4', 'hp5', 'hp6', 'hp7', 'hp8', 'hp9', 'hp10', 'about1_id', 'about2_id', 'about3_id', 'tip1_id', 'tip2_id', 'tip3_id', 'contact_texts_id', 'quote_texts_id', 'demographics_id')) ->join(array('d' => 'demographics'), 'w.demographics_id = d.id', array('total_population')) ->order(array('total_population DESC', 'kw_location')); $paginator = new Zend_Paginator(new Zend_Paginator_Adapter_DbSelect($select)); $paginator->setItemCountPerPage(50); $paginator->setCurrentPageNumber($currentPage); $paginator->setPageRange(($paginator->getTotalItemCount() / 50) + 1); $this->view->paginator = $paginator; $numWebsitesOnline = $websites->getWebsitesOnline(); On the php page I have this code to call the websites that are in the database to a list: <p class="red"> Websites online: <?php echo $this->numOnline; ?> </p> <?php print_r(count($this->paginator)); ?> <?php if(count($this->paginator)): ?> <table class="table-list"> <?php foreach($this->paginator as $item): ?> <tr> <?php if($this->userIsAllowedAction('websites', 'reload')): ?> <td class="center noborder w30"> <img class="hidden" src="<?php echo $this->baseUrl() . '/images/loader.gif' ?>" alt="Loading..."/><a class="reload" title="refresh" href="<?php echo $this->baseUrl(); ?>/utils/ui/refresh-website.php" rel="<?php echo urlencode('http://' . $item['url'] . '/install.php'); ?>,<?php echo urlencode($item['ftp_server']); ?>,<?php echo $item['ftp_username']; ?>,<?php echo $item['ftp_password']; ?>,<?php echo $item['ftp_folder']; ?>,<?php echo $this->baseUrl(); ?>,<?php echo $item['id']; ?>"><img src="<?php echo $this->baseUrl(); ?>/images/icon-refresh.png" alt="Refresh"/></a> </td> <?php endif; ?> <td class="center noborder w30"> <?php if($this->userIsAllowedAction('websites', 'edit')): ?><a title="Edit" href="<?php echo $this->url(array('controller' => 'websites', 'action' => 'edit', 'id' => $item['id'])); ?>"><img src="<?php echo $this->baseUrl(); ?>/images/icon-edit.png" alt="Edit"/></a><?php endif; ?> </td> <td class="center noborder w30"> <?php if($this->userIsAllowedAction('websites', 'remove')): ?><a title="Remove" href="<?php echo $this->url(array('controller' => 'websites', 'action' => 'remove', 'id' => $item['id'])); ?>"><img src="<?php echo $this->baseUrl(); ?>/images/icon-delete.png" alt="Remove"/></a><?php endif; ?> </td> <td> <?php if($item['online']): ?> <span class="hidden"><?php echo trim($this->escape($item['kw_adjective'] . $item['kw_name'])); ?></span><a class="goto-website" href="http://<?php echo $item['url']; ?>" target="_blank"><?php echo $this->escape($item['kw_location']); ?></a> <?php else: ?> <?php echo $this->escape($item['kw_location']); ?> <?php endif; ?> </td> <td class="center population"> <?php if($item['total_population'] >= 0) echo $item['total_population']; ?> </td> <td class="center"> <?php if(!empty($item['url'])): ?><img src="<?php echo $this->baseUrl(); ?>/images/check_mark.png" alt="DONE"/><?php endif; ?> </td> <td class="center"> <?php if(!empty($item['email'])): ?><img src="<?php echo $this->baseUrl(); ?>/images/check_mark.png" alt="DONE"/><?php endif; ?> </td> <td class="center"> <?php if($item['demographics_id']): ?><img src="<?php echo $this->baseUrl(); ?>/images/check_mark.png" alt="DONE"/><?php endif; ?> </td> <td class="center"> <?php if($item['hp1'] && $item['hp2'] && $item['hp3'] && $item['hp4'] && $item['hp5'] && $item['hp6'] && $item['hp7'] && $item['hp8'] && $item['hp9'] && $item['hp10'] && $item['about1_id'] && $item['about2_id'] && $item['about3_id'] && $item['tip1_id'] && $item['tip2_id'] && $item['tip3_id'] && $item['contact_texts_id'] && $item['quote_texts_id']): ?><img src="<?php echo $this->baseUrl(); ?>/images/check_mark.png" alt="DONE"/><?php endif; ?> </td> <td class="center"> <?php if(file_exists($_SERVER['DOCUMENT_ROOT'] . $this->baseUrl() . Zend_Registry::get('assets_base_path') . '/' . $item['id'] . '/header.jpg')): ?><img src="<?php echo $this->baseUrl(); ?>/images/check_mark.png" alt="DONE"/><?php endif; ?> </td> <td class="center"> <?php if(($item['bg_color'] != '' && $item['bg_color'] != 'e6e6e6') || ($item['dark_color'] != '' && $item['dark_color'] != '003e75') || ($item['light_color'] != '' && $item['light_color'] != '3073ad') || ($item['links_color'] != '' && $item['links_color'] != '255593') || ($item['text_color'] != '' && $item['text_color'] != '4f4f4f')): ?> <img src="<?php echo $this->baseUrl(); ?>/images/check_mark.png" alt="DONE"/> <?php endif; ?> </td> <td class="center"> <?php if($item['image1_id'] && $item['image2_id'] && $item['image3_id']): ?><img src="<?php echo $this->baseUrl(); ?>/images/check_mark.png" alt="DONE"/><?php endif; ?> </td> <td class="center"> <?php if(!empty($item['twitter_user'])): ?><img src="<?php echo $this->baseUrl(); ?>/images/check_mark.png" alt="DONE"/><?php endif; ?> </td> <td class="center"> <?php if(!empty($item['facebook_id'])): ?><img src="<?php echo $this->baseUrl(); ?>/images/check_mark.png" alt="DONE"/><?php endif; ?> </td> <td class="center"> <?php if(!empty($item['phone_number'])): ?><img src="<?php echo $this->baseUrl(); ?>/images/check_mark.png" alt="DONE"/><?php endif; ?> </td> <td class="center"> <?php if($item['google_account']): ?><img src="<?php echo $this->baseUrl(); ?>/images/check_mark.png" alt="DONE"/><?php endif; ?> </td> <td class="center"> <?php if($item['video_made']): ?><img src="<?php echo $this->baseUrl(); ?>/images/check_mark.png" alt="DONE"/><?php endif; ?> </td> <td class="center"> <?php if($item['youtube_position']) { echo $item['youtube_position']; }; ?> </td> <td class="center"> <?php if(!empty($item['address'])): ?><img src="<?php echo $this->baseUrl(); ?>/images/check_mark.png" alt="DONE"/><?php endif; ?> </td> <td class="center"> <?php if($item['gmaps_status'] == 1): ?><img src="<?php echo $this->baseUrl(); ?>/images/icon-gmapspending.png" alt="Pending"/><?php elseif($item['gmaps_status'] == 2): ?><img src="<?php echo $this->baseUrl(); ?>/images/check_mark.png" alt="DONE"/><?php endif; ?> </td> <td class="center"> <?php if(!empty($item['ganalytics'])): ?><img src="<?php echo $this->baseUrl(); ?>/images/check_mark.png" alt="DONE"/><?php endif; ?> </td> <td class="center"> <?php if($item['online']): ?><img src="<?php echo $this->baseUrl(); ?>/images/check_mark_red.png" alt="Online!"/><?php endif; ?> </td> <td class="center"> <?php if($item['indexed']): ?><img src="<?php echo $this->baseUrl(); ?>/images/check_mark_red.png" alt="Online!"/><?php endif; ?> </td> <td class="center"> <?php if($item['gmap_position']) { echo $item['gmap_position']; }; ?> </td> <td class="center"> <?php if($item['google_position']) { echo $item['google_position']; }; ?> </td> </tr> <?php endforeach; ?> </table> <?php endif; ?> The print_r(count($this-paginator)); line is returning "0", and the $this-numOnline; line is returning 1. So it sees that there is one row in the websites table of the database, but it is not returning anything to page and listing out the rows in the websites table. Not sure if this is the paginator that is causing this cause it is returning 0 or something else I don't know about.

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jQuery JSON encode set of input values

- by gurun8

I need tp serialize a group of input elements but I can't for the life of me figure out this simple task. I can successfully iterate through the targeted inputs using: $("#tr_Features :input").each(function() { ... } Here's my code, that doesn't work: var features = new Array(); $("#tr_Features :input").each(function() { features += {$(this).attr("name"): $(this).val()}; } Serializing the entire form won't give me what I need. The form has much more than this subset of inputs. This seems like it should be a pretty straightforward task but apparently programming late into a Friday afternoon isn't a good thing. If it's helpful, here's the form inputs I'm targeting: <table cellspacing="0" border="0" id="TblGrid_list" class="EditTable" cellpading="0"> <tbody><tr id="tr_Features" class="FormData" rowpos="1"> <td class="CaptionTD ui-widget-content">Cable Family</td> <td id="td_Features" class="DataTD ui-widget-content" style="white-space: pre;"> <input type="text" value="" id="feature_id:8" name="feature_id:8"></td> </tr> <tr id="tr_Features" class="FormData" rowpos="1"> <td class="CaptionTD ui-widget-content">Material</td> <td id="td_Features" class="DataTD ui-widget-content" style="white-space: pre;"> <input type="text" value="" id="feature_id:9" name="feature_id:9"></td> </tr> <tr id="tr_Features" class="FormData" rowpos="1"> <td class="CaptionTD ui-widget-content">Thread Size</td> <td id="td_Features" class="DataTD ui-widget-content" style="white-space: pre;"> <input type="text" value="" id="feature_id:10" name="feature_id:10"></td> </tr> <tr id="tr_Features" class="FormData" rowpos="1"> <td class="CaptionTD ui-widget-content">Attachment Style</td> <td id="td_Features" class="DataTD ui-widget-content" style="white-space: pre;"> <input type="text" value="" id="feature_id:11" name="feature_id:11"></td> </tr> <tr id="tr_Features" class="FormData" rowpos="1"> <td class="CaptionTD ui-widget-content">Feature</td> <td id="td_Features" class="DataTD ui-widget-content" style="white-space: pre;"> <input type="text" value="" id="feature_id:12" name="feature_id:12"></td> </tr> <tr id="tr_Features" class="FormData" rowpos="1"> <td class="CaptionTD ui-widget-content">Comments</td> <td id="td_Features" class="DataTD ui-widget-content" style="white-space: pre;"> <input type="text" value="" id="feature_id:13" name="feature_id:13"></td> </tr> </tbody></table>

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Mimicking a HBox / VBox with CSS

- by Daniel Hai

I'm an old school tables guy, and am pretty baffled when it comes to modern HTML. I'm trying to something as simple as vertical / horizontal layouts (i.e. Flex's hbox/vbox), but am having major difficulty replicating them. An old table would look something like this for an HBox: <table width="100%" height="100"> <tr valign="middle"> <td nowrap style="background-color:#CCC">I am text on grey</td> <td width="50%" valign="top">displays top</td> <td width="50%" align="right">Autosize Fill (displays bottom right)</td> </tr> </table> Now I'm trying to do this with div's, but to no avail. When using display:inline, I cannot set a percentage width -- it only takes explicit widths. When using float:left, settings 100% percentage width causes it to really be 100% and pushes the next div down. Here's the code I've been playing with: <html> <head> </head> <style type="text/css"> div.test { background-color: #EE9; padding:5px;} body { font-family: Arial; } ul { list-style-type:none; } ul li { float:left; } .hboxinline div { display: inline; } .hboxfloat div { float:left; } .cellA { background-color:#CCC; width:100%; } .cellB { background-color:#DDD; min-width:100; } .cellC { background-color:#EEE; min-width:200; } </style> <body> A = 100%, b = 100, c = 200 <div class="test">old school table <table cellpadding="0" cellspacing="0"> <tr> <td class="cellA">A</td> <td class="cellB">B</td> <td class="cellC">C</td> </tr> </table></div> <br/> <div class="test"> float:left <div class="hboxinline"> <div class="cellA">A</div> <div class="cellB">B</div> <div class="cellC">C</div> </div> </div> <br/> <div class="test">ul / li <ul class="ulli"> <li class="cellA">A</li> <li class="cellB">B</li> <li class="cellC">C</li> </ul> </div> <br/> <div class="test"> display:inline <div class="hboxfloat"> <div class="cellA">A</div> <div class="cellB">B</div> <div class="cellC">C</div> </div> </div> </body> </html>

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Copying values of one table to another (how to convert this js function to jQuery)

- by Sullan

Hi All, I am stuck with a small problem here.. What i am trying to do is copy description of id's from one table to another. I have writter half of the javascript and can anybody tell me how to convert this function in jquery. I want the description copied from the first table based on the id to the second table. Have done this in jquery using 'contains', (http://stackoverflow.com/questions/2449845/comparing-2-tables-column-values-and-copying-the-next-column-content-to-the-secon) since there are 1000 table rows, the explorer crashes. Is there a way to simplify it ??... the code is as follows... the current javascript works when i click on test in the second table, but i want the value to be appended in the second table on page load... pls help <table class="reportTabe"> <tr><td>psx-pdu120v1</td><td class="itemname" id="psx-pdu120v1">some description1</td></tr> <tr><td>psx-pdu120v1</td><td class="itemname" id="psx-pdu120v1">some description1</td></tr> <tr><td>psx-pdu120v3</td><td class="itemname" id="psx-pdu120v3">some description3</td></tr> <tr><td>psx-pdu120v4</td><td class="itemname" id="psx-pdu120v4">some description4</td></tr> <tr><td>psx-pdu120v5</td><td class="itemname" id="psx-pdu120v5">some description5</td></tr> <tr><td>psx-pdu120v6</td><td class="itemname" id="psx-pdu120v6">some description6</td></tr> <tr><td>psx-pdu120v7</td><td class="itemname" id="psx-pdu120v7">some description7</td></tr> <tr><td>psx-pdu120v8</td><td class="itemname" id="psx-pdu120v8">some description8</td></tr> <tr><td>psx-pdu120v9</td><td class="itemname" id="psx-pdu120v9">some description9</td></tr> </table> <table class="data"> <tr><td class="whipItem">psx-pdu120v1</td><td onClick="Javascript:alert(document.getElementById('psx-pdu120v1').innerText)";>test</td></tr> <tr><td class="whipItem">psx-pdu120v3</td><td onClick="Javascript:alert(document.getElementById('psx-pdu120v1').innerText)";>test</td></tr> <tr><td class="whipItem">psx-pdu120v4</td><td onClick="Javascript:alert(document.getElementById('psx-pdu120v5').innerText)";>test</td></tr> <tr><td class="whipItem">psx-pdu120v5</td><td Javascript:this.innerText=document.getElementById('psx-pdu120v4').innerText;></td></tr> <tr><td class="whipItem">psx-pdu120v6</td><td Javascript:this.innerText=document.getElementById('psx-pdu120v5').innerText;></td></tr> <tr><td class="whipItem">psx-pdu120v7</td><td Javascript:this.innerText=document.getElementById('psx-pdu120v6').innerText;></td></tr> <tr><td class="whipItem">psx-pdu120v8</td><td Javascript:this.innerText=document.getElementById('psx-pdu120v7').innerText;></td></tr> <tr><td class="whipItem">psx-pdu120v9</td><td Javascript:this.innerText=document.getElementById('psx-pdu120v8').innerText;></td></tr> </table>

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HQL over ternary map with subcollection

- by Diego Mijelshon

I'm stuck with a query I need to write. Given the following model: public class A : Entity<Guid> { public virtual IDictionary<B, C> C { get; set; } } public class B : Entity<Guid> { } public class C : Entity<Guid> { public virtual int Data1 { get; set; } public virtual ICollection<D> D { get; set; } } public class D : Entity<Guid> { public virtual int Data2 { get; set; } } I need to get a list of A instances that have a D containing some data for the specified B (parameter) In the object model, that would be: listOfA.Where(a => a.C[b].D.Any(d => d.Data2 == 0)) But I wasn't able to write a working HQL. I'm able to write something like the following, which filters on C.Data1: from A a where a.C[:b].Data1 = 0 But I'm unable to do anything with the elements of a.C[:b].D (I get various parsing exceptions) Here are the mappings, in case you're interested (nothing special, generated by ConfORM): <class name="A"> <id name="Id" type="Guid"> <generator class="guid.comb" /> </id> <map name="C"> <key column="a_key" /> <map-key-many-to-many class="B" /> <one-to-many class="C" /> </map> </class> <class name="B"> <id name="Id" type="Guid"> <generator class="guid.comb" /> </id> </class> <class name="C"> <id name="Id" type="Guid"> <generator class="guid.comb" /> </id> <property name="Data1" /> <bag name="D"> <key column="c_key" /> <one-to-many class="D" /> </bag> </class> <class name="D"> <id name="Id" type="Guid"> <generator class="guid.comb" /> </id> <property name="Data2" /> </class> Thanks!

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jquery remove selected element and append to another

- by KnockKnockWhosThere

I'm trying to re-append a "removed option" to the appropriate select option menu. I have three select boxes: "Categories", "Variables", and "Target". "Categories" is a chained select, so when the user selects an option from it, the "Variables" select box is populated with options specific to the selected categories option. When the user chooses an option from the "Variables" select box, it's appended to the "Target" select box. I have a "remove selected" feature so that if a user "removes" a selected element from the "Target" select box, it's removed from "Target" and put back into the pool of "Variables" options. The problem I'm having is that it appends the option to the "Variables" items indiscriminately. That is, if the selected category is "Age" the "Variables" options all have a class of "age". But, if the removed option is an "income" item, it will display in the "Age Variables" option list. Here's the HTML markup: <select multiple="" id="categories" name="categories[]"> <option class="category" value="income">income</option> <option class="category" value="gender">gender</option> <option class="category" value="age">age</option> </select> <select multiple="multiple" id="variables" name="variables[]"> <option class="income" value="10">$90,000 - $99,999</option> <option class="income" value="11">$100,000 - $124,999</option> <option class="income" value="12">$125,000 - $149,999</option> <option class="income" value="13">Greater than $149,999</option> <option class="gender" value="14">Male</option> <option class="gender" value="15">Female</option> <option class="gender" value="16">Ungendered</option> <option class="age" value="17">Ages 18-24</option> <option class="age" value="18">Ages 25-34</option> <option class="age" value="19">Ages 35-44</option> </select> <select height="60" multiple="multiple" id="target" name="target[]"> </select> And, here's the js: /* This determines what options are display in the "Variables" select box */ var cat = $('#categories'); var el = $('#variables'); $('#categories option').click(function() { var class = $(this).val(); $('#variables option').each(function() { if($(this).hasClass(class)) { $(this).show(); } else { $(this).hide(); } }); }); /* This adds the option to the target select box if the user clicks "add" */ $('#add').click(function() { return !$('#variables option:selected').appendTo('#target'); }); /* This is the remove function in its current form, but doesn't append correctly */ $('#remove').click(function() { $('#target option:selected').each(function() { var class = $(this).attr('class'); if($('#variables option').hasClass(class)) { $(this).appendTo('#variables'); sortList('variables'); } }); });

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Get Two row with multiple column in asp.net c#

- by Gaurav Naik

How to get data from database with two rows and multiple column with seperator will be there after the 1 row end as an example: <div class="_thum_bar"> <div class="box1"> <div class="_t1_box"><a href="#!/condom_details"><img src="images/pack/pack1.png" border="0"></a></div> <div class="_t2_box"> <h1>Dotted Condom</h1> <p>Dotted condoms for additional friction. Pure ecstasy makes this a KamaSutra all time favourite.</p> <h2><a href="#!/condom_details">Add to cart</a></h2> </div> </div> <div class="box2"> <div class="_t1_box"><a href="#!/condom_details"><img src="images/pack/pack1.png" border="0"></a></div> <div class="_t2_box"> <h1>Dotted Condom</h1> <p>Dotted condoms for additional friction. Pure ecstasy makes this a KamaSutra all time favourite.</p> <h2><a href="#!/condom_details">Add to cart</a></h2> </div> </div> <div class="box3"> <div class="_t1_box"><a href="#"><img src="images/pack/pack1.png" border="0"></a></div> <div class="_t2_box"> <h1>Dotted Condom</h1> <p>Dotted condoms for additional friction. Pure ecstasy makes this a KamaSutra all time favourite.</p> <h2><a href="#!/condom_details">Add to cart</a></h2> </div> </div> </div> <div class="_t_spacer"> </div> <div class="_thum_bar"> <div class="box1"> <div class="_t1_box"><a href="#!/condom_details"><img src="images/pack/pack1.png" border="0"></a></div> <div class="_t2_box"> <h1>Dotted Condom</h1> <p>Dotted condoms for additional friction. Pure ecstasy makes this a KamaSutra all time favourite.</p> <h2><a href="#!/condom_details">Add to cart</a></h2> </div> </div> <div class="box2"> <div class="_t1_box"><a href="#!/condom_details"><img src="images/pack/pack1.png" border="0"></a></div> <div class="_t2_box"> <h1>Dotted Condom</h1> <p>Dotted condoms for additional friction. Pure ecstasy makes this a KamaSutra all time favourite.</p> <h2><a href="#!/condom_details">Add to cart</a></h2> </div> </div> </div> <div class="_t_spacer"> </div>

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Finding Image and Place into another img source

- by saorabh

My Html Markup is like this <div id="main"> <div id="slider"> <img src=""/> </div> <div class="clear slider"></div> <div class="slider ndslider"> <a href="#" rel="bookmark"> <img src="#" title=""/> </a> </div> <div class="slider rdslider"> <a href="" rel="bookmark"> <img src="" title=""/> </a> </div> <div class="slider thslider nivoSlider"> <a rel="bookmark" href="" class="nivo-imageLink" > <img src="image src" > </a> <a rel="bookmark" href="" class="nivo-imageLink"> <img title="" src=""> </a> <a rel="bookmark" href="#" class="nivo-imageLink"> <img title="" src=""> </a> <div class="nivo-slice"></div> <div class="nivo-slice"></div> <div class="nivo-slice"></div> <div class="nivo-directionNav"> <a class="nivo-prevNav">Prev</a> <a class="nivo-nextNav">Next</a> </div> <div class="nivo-controlNav"> <a rel="0" class="nivo-control active"> <img alt="" src="undefined"> </a> <a rel="1" class="nivo-control"> <img alt="" src="undefined"> </a> </div> </div> </div> I want to find the all the images inside this DIV <div class="slider thslider nivoSlider"> </div> and set that images on to this <div class="nivo-controlNav"> <a rel="0" class="nivo-control active"> <img alt="" src="undefined"> </a> </div> For Doing the same i had written my custom jQuery but it is not working. jQuery(document).ready(function() { jQuery('.thslider a img').each(function(){ var imgSrc = jQuery(this).attr('src'); var newSrc = 'http://saorabh-test1.rtcamp.info/wp-content/themes/twentyten/timthumb.php?src='+ imgSrc +' &h=50&w=50&zc=1'; jQuery(".thslider .nivo-controlNav a img").attr('src',newSrc); }); }); Help me..

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microsoft access query speed...

- by V.S.

Hello everyone! I am now writing a report about MS Access and I can't find any information about its performance speed in comparison to other alternatives such as Micorsoft SQL Server, MySQL, Oracle, etc... It's obvious that MS Access is going to be the slowest among the rest, but there is no solid documents confirming this other than forums threads, and I don't have the time and resources to do the research myself :( Hoping for your help, V.S.

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if statement to check available elements

- by nicmare

Hi there, i allways found an answer here just be reading the threads but now its time for my very first thread because i was unable to find related questions: this is my target code: <li> <span class="panel"> <a href="…" class="image" rel="group"> <img title="…" src="…" alt="…" width="128" height="96" /> </a> <span class="sizes"> <span class="button"> <a href="#" class="size1" rel="…" title="1">9x13</a> </span> <span class="button"> <a href="#" class="size2" rel="…" title="3">10x15</a> </span> <span class="button"> <a href="#" class="size3" rel="…" title="6">20x30</a> </span> </span> </span> <a href="…" class="image" rel="group"> <span class="added"></span> <img title="…" src="…" alt="…" width="128" height="96" class="thumbnail" /> </a> </li> i add two "span" elements through jquery: $('.sizes a').click( function (e) { e.preventDefault(); $(this).after("<span class='checked'></span><span class='remove'></span>"); } ); the maximum amount of those s are 3 times in a wrapped div. so i am trying to do is the following: $(".remove").live('click', function(){ $(this).hide(); $(this).prev().hide(); // hide checked span if ($(this).parent().parent().children().children().each().hasClass('checked')) { $(this).parent().parent().parent().next().children(".added").hide(); } } ); of course my if statement is crap. i try it in my own words: if there are more than one span(class=remove) in span(class=panel) then nothing should happen. but if there is just one span(class=remove) left in span(class=panel) THEN should be hidden how do i achieve this? there is an online demonstration of this: http://bit.ly/972be4 as you can see, every time when i hit a button below an image, the image gets marked by a label. and i want to hide this label (class=added) when no button is selected Thank you very much! best wishes from germany

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C#: Handling Notifications: inheritance, events, or delegates?

- by James Michael Hare

Often times as developers we have to design a class where we get notification when certain things happen. In older object-oriented code this would often be implemented by overriding methods -- with events, delegates, and interfaces, however, we have far more elegant options. So, when should you use each of these methods and what are their strengths and weaknesses? Now, for the purposes of this article when I say notification, I'm just talking about ways for a class to let a user know that something has occurred. This can be through any programmatic means such as inheritance, events, delegates, etc. So let's build some context. I'm sitting here thinking about a provider neutral messaging layer for the place I work, and I got to the point where I needed to design the message subscriber which will receive messages from the message bus. Basically, what we want is to be able to create a message listener and have it be called whenever a new message arrives. Now, back before the flood we would have done this via inheritance and an abstract class: 1: 2: // using inheritance - omitting argument null checks and halt logic 3: public abstract class MessageListener 4: { 5: private ISubscriber _subscriber; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8: 9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber) 11: { 12: _subscriber = subscriber; 13: _messageThread = new Thread(MessageLoop); 14: _messageThread.Start(); 15: } 16: 17: // user will override this to process their messages 18: protected abstract void OnMessageReceived(Message msg); 19: 20: // handle the looping in the thread 21: private void MessageLoop() 22: { 23: while(!_isHalted) 24: { 25: // as long as processing, wait 1 second for message 26: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 27: if(msg != null) 28: { 29: OnMessageReceived(msg); 30: } 31: } 32: } 33: ... 34: } It seems so odd to write this kind of code now. Does it feel odd to you? Maybe it's just because I've gotten so used to delegation that I really don't like the feel of this. To me it is akin to saying that if I want to drive my car I need to derive a new instance of it just to put myself in the driver's seat. And yet, unquestionably, five years ago I would have probably written the code as you see above. To me, inheritance is a flawed approach for notifications due to several reasons: Inheritance is one of the HIGHEST forms of coupling. You can't seal the listener class because it depends on sub-classing to work. Because C# does not allow multiple-inheritance, I've spent my one inheritance implementing this class. Every time you need to listen to a bus, you have to derive a class which leads to lots of trivial sub-classes. The act of consuming a message should be a separate responsibility than the act of listening for a message (SRP). Inheritance is such a strong statement (this IS-A that) that it should only be used in building type hierarchies and not for overriding use-specific behaviors and notifications. Chances are, if a class needs to be inherited to be used, it most likely is not designed as well as it could be in today's modern programming languages. So lets look at the other tools available to us for getting notified instead. Here's a few other choices to consider. Have the listener expose a MessageReceived event. Have the listener accept a new IMessageHandler interface instance. Have the listener accept an Action<Message> delegate. Really, all of these are different forms of delegation. Now, .NET events are a bit heavier than the other types of delegates in terms of run-time execution, but they are a great way to allow others using your class to subscribe to your events: 1: // using event - ommiting argument null checks and halt logic 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private bool _isHalted = false; 6: private Thread _messageThread; 7: 8: // assign the subscriber and start the messaging loop 9: public MessageListener(ISubscriber subscriber) 10: { 11: _subscriber = subscriber; 12: _messageThread = new Thread(MessageLoop); 13: _messageThread.Start(); 14: } 15: 16: // user will override this to process their messages 17: public event Action<Message> MessageReceived; 18: 19: // handle the looping in the thread 20: private void MessageLoop() 21: { 22: while(!_isHalted) 23: { 24: // as long as processing, wait 1 second for message 25: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 26: if(msg != null && MessageReceived != null) 27: { 28: MessageReceived(msg); 29: } 30: } 31: } 32: } Note, now we can seal the class to avoid changes and the user just needs to provide a message handling method: 1: theListener.MessageReceived += CustomReceiveMethod; However, personally I don't think events hold up as well in this case because events are largely optional. To me, what is the point of a listener if you create one with no event listeners? So in my mind, use events when handling the notification is optional. So how about the delegation via interface? I personally like this method quite a bit. Basically what it does is similar to inheritance method mentioned first, but better because it makes it easy to split the part of the class that doesn't change (the base listener behavior) from the part that does change (the user-specified action after receiving a message). So assuming we had an interface like: 1: public interface IMessageHandler 2: { 3: void OnMessageReceived(Message receivedMessage); 4: } Our listener would look like this: 1: // using delegation via interface - omitting argument null checks and halt logic 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private IMessageHandler _handler; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8: 9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber, IMessageHandler handler) 11: { 12: _subscriber = subscriber; 13: _handler = handler; 14: _messageThread = new Thread(MessageLoop); 15: _messageThread.Start(); 16: } 17: 18: // handle the looping in the thread 19: private void MessageLoop() 20: { 21: while(!_isHalted) 22: { 23: // as long as processing, wait 1 second for message 24: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 25: if(msg != null) 26: { 27: _handler.OnMessageReceived(msg); 28: } 29: } 30: } 31: } And they would call it by creating a class that implements IMessageHandler and pass that instance into the constructor of the listener. I like that this alleviates the issues of inheritance and essentially forces you to provide a handler (as opposed to events) on construction. Well, this is good, but personally I think we could go one step further. While I like this better than events or inheritance, it still forces you to implement a specific method name. What if that name collides? Furthermore if you have lots of these you end up either with large classes inheriting multiple interfaces to implement one method, or lots of small classes. Also, if you had one class that wanted to manage messages from two different subscribers differently, it wouldn't be able to because the interface can't be overloaded. This brings me to using delegates directly. In general, every time I think about creating an interface for something, and if that interface contains only one method, I start thinking a delegate is a better approach. Now, that said delegates don't accomplish everything an interface can. Obviously having the interface allows you to refer to the classes that implement the interface which can be very handy. In this case, though, really all you want is a method to handle the messages. So let's look at a method delegate: 1: // using delegation via delegate - omitting argument null checks and halt logic 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private Action<Message> _handler; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8: 9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber, Action<Message> handler) 11: { 12: _subscriber = subscriber; 13: _handler = handler; 14: _messageThread = new Thread(MessageLoop); 15: _messageThread.Start(); 16: } 17: 18: // handle the looping in the thread 19: private void MessageLoop() 20: { 21: while(!_isHalted) 22: { 23: // as long as processing, wait 1 second for message 24: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 25: if(msg != null) 26: { 27: _handler(msg); 28: } 29: } 30: } 31: } Here the MessageListener now takes an Action<Message>. For those of you unfamiliar with the pre-defined delegate types in .NET, that is a method with the signature: void SomeMethodName(Message). The great thing about delegates is it gives you a lot of power. You could create an anonymous delegate, a lambda, or specify any other method as long as it satisfies the Action<Message> signature. This way, you don't need to define an arbitrary helper class or name the method a specific thing. Incidentally, we could combine both the interface and delegate approach to allow maximum flexibility. Doing this, the user could either pass in a delegate, or specify a delegate interface: 1: // using delegation - give users choice of interface or delegate 2: public sealed class MessageListener 3: { 4: private ISubscriber _subscriber; 5: private Action<Message> _handler; 6: private bool _isHalted = false; 7: private Thread _messageThread; 8: 9: // assign the subscriber and start the messaging loop 10: public MessageListener(ISubscriber subscriber, Action<Message> handler) 11: { 12: _subscriber = subscriber; 13: _handler = handler; 14: _messageThread = new Thread(MessageLoop); 15: _messageThread.Start(); 16: } 17: 18: // passes the interface method as a delegate using method group 19: public MessageListener(ISubscriber subscriber, IMessageHandler handler) 20: : this(subscriber, handler.OnMessageReceived) 21: { 22: } 23: 24: // handle the looping in the thread 25: private void MessageLoop() 26: { 27: while(!_isHalted) 28: { 29: // as long as processing, wait 1 second for message 30: Message msg = _subscriber.Receive(TimeSpan.FromSeconds(1)); 31: if(msg != null) 32: { 33: _handler(msg); 34: } 35: } 36: } 37: } } This is the method I tend to prefer because it allows the user of the class to choose which method works best for them. You may be curious about the actual performance of these different methods. 1: Enter iterations: 2: 1000000 3: 4: Inheritance took 4 ms. 5: Events took 7 ms. 6: Interface delegation took 4 ms. 7: Lambda delegate took 5 ms. Before you get too caught up in the numbers, however, keep in mind that this is performance over over 1,000,000 iterations. Since they are all < 10 ms which boils down to fractions of a micro-second per iteration so really any of them are a fine choice performance wise. As such, I think the choice of what to do really boils down to what you're trying to do. Here's my guidelines: Inheritance should be used only when defining a collection of related types with implementation specific behaviors, it should not be used as a hook for users to add their own functionality. Events should be used when subscription is optional or multi-cast is desired. Interface delegation should be used when you wish to refer to implementing classes by the interface type or if the type requires several methods to be implemented. Delegate method delegation should be used when you only need to provide one method and do not need to refer to implementers by the interface name.

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What’s new in MVVM Light V3

- by Laurent Bugnion

V3 of the MVVM Light Toolkit was released during MIX10, after quite a long alpha stage. This post lists the new features in MVVM Light V3. Compatibility MVVM Light Toolkit V3 can be installed for the following tools and framework versions: Visual Studio 2008 SP1, Expression Blend 3 Windows Presentation Foundation 3.5 SP1 Silverlight 3 Visual Studio 2010 RC, Expression Blend 4 beta Windows Presentation Foundation 3.5 SP1 Windows Presentation Foundation 4 RC Silverlight 3 Silverlight 4 RC For more information about installing the MVVM Light Toolkit V3, please visit this page. For cleaning up existing installation, see this page. New in V3 RTM The following features have been added after V3 alpha3: Project template for the Windows Phone 7 series (Silverlight) This new template allows you to create a new MVVM Light application in Visual Studio 2010 RC and to run it in the Windows Phone 7 series emulator. This template uses the Silverlight 3 version of the MVVM Light Toolkit V3. At this time, only the essentials features of the GalaSoft.MvvmLight.dll assembly are supported on the phone. New in V3 alpha3 The following features have been added after V3 alpha2: New logo An awesome logo has been designed for MVVM Light by Philippe Schutz. DispatcherHelper class (in GalaSoft.MvvmLight.Extras.dll) This class is useful when you work on multi-threaded WPF or Silverlight applications. Initializing: The DispatcherHelper class must be initialized in the UI thread. For example, you can initialize the class in a Silverlight application’s Application_Startup event handler, or in the WPF application’s static App constructor (in App.xaml). // Initializing in Silverlight (in App.xaml) private void Application_Startup( object sender, StartupEventArgs e) { RootVisual = new MainPage(); DispatcherHelper.Initialize(); } // Initializing in WPF (in App.xaml) static App() { DispatcherHelper.Initialize(); } Verifying if a property exists The ViewModelBase.RaisePropertyChanged method now checks if a given property name exists on the ViewModel class, and throws an exception if that property cannot be found. This is useful to detect typos in a property name, for example during a refactoring. Note that the check is only done in DEBUG mode. Replacing IDisposable with ICleanup The IDisposable implementation in the ViewModelBase class has been marked obsolete. Instead, the ICleanup interface (and its Cleanup method) has been added. Implementing IDisposable in a ViewModel is still possible, but must be done explicitly. IDisposable in ViewModelBase was a bad practice, because it supposes that the ViewModel is garbage collected after Dispose is called. instead, the Cleanup method does not have such expectation. The ViewModelLocator class (created when an MVVM Light project template is used in Visual Studio or Expression Blend) exposes a static Cleanup method, which should in turn call each ViewModel’s Cleanup method. The ViewModel is free to override the Cleanup method if local cleanup must be performed. Passing EventArgs to command with EventToCommand The EventToCommand class is used to bind any event to an ICommand (typically on the ViewModel). In this case, it can be useful to pass the event’s EventArgs parameter to the command in the ViewModel. For example, for the MouseEnter event, you can pass the MouseEventArgs to a RelayCommand<MouseEventArgs> as shown in the next listings. Note: Bringing UI specific classes (such as EventArgs) into the ViewModel reduces the testability of the ViewModel, and thus should be used with care. Setting EventToCommand and PassEventArgsToCommand: <Grid x:Name="LayoutRoot"> <i:Interaction.Triggers> <i:EventTrigger EventName="MouseEnter"> <cmd:EventToCommand Command="{Binding MyCommand}" PassEventArgsToCommand="True" /> </i:EventTrigger> </i:Interaction.Triggers> </Grid> Getting the EventArgs in the command public RelayCommand<MouseEventArgs> MyCommand { get; private set; } public MainViewModel() { MyCommand = new RelayCommand<MouseEventArgs>(e => { // e is of type MouseEventArgs }); } Changes to templates Various changes have been made to project templates and item templates to make them more compatible with Silverlight 4 and to improve their visibility in Visual Studio and Expression Blend. Bug corrections When a message is sent through the Messenger class using the method Messenger.Default.Send<T>(T message, object token), and the token is a simple value (for example int), the message was not sent correctly. This bug is now corrected. New in V3 The following features have been added after V2. Sending messages with callback Certain classes have been added to the GalaSoft.MvvmLight.Messaging namespace, allowing sending a message and getting a callback from the recipient. These classes are: NotificationMessageWithCallback: Base class for messages with callback. NotificationMessageAction: A class with string notification, and a parameterless callback. NotificationMessageAction<T>: A class with string notification, and a callback with a parameter of type T. To send a message with callback, use the following code: var message = new NotificationMessageAction<bool>( "Hello world", callbackMessage => { // This is the callback code if (callbackMessage) { // ... } }); Messenger.Default.Send(message); To register and receive a message with callback, use the following code: Messenger.Default.Register<NotificationMessageAction<bool>>( this, message => { // Do something // Execute the callback message.Execute(true); }); Messenger.Default can be overriden The Messenger.Default property can also be replaced, for example for unit testing purposes, by using the Messenger.OverrideDefault method. All the public methods of the Messenger class have been made virtual, and can be overridden in the test messenger class. Sending messages to interfaces In V2, it was possible to deliver messages targeted to instances of a given class. in V3 it is still possible, but in addition you can deliver a message to instances that implement a certain interface. The message will not be delivered to other recipients. Use the overload Messenger.Default.Send<TMessage, TTarget>(TMessage message) where TTarget is, in fact, an interface (for example IDisposable). Of course the recipient must register to receive the type of message TMessage. Sending messages with a token Messages can now be sent through the Messenger with a token. To send a message with token, use the method overload Send<TMessage>(TMessage message, object token). To receive a message with token, use the methods Register<TMessage>(object recipient, object token, Action<TMessage> action) or Register<TMessage>(object recipient, object token, bool receiveDerivedMessagesToo, Action<TMessage> action) The token can be a simple value (int, string, etc…) or an instance of a class. The message is not delivered to recipients who registered with a different token, or with no token at all. Renaming CommandMessage to NotificationMessage To avoid confusion with ICommand and RelayCommand, the CommandMessage class has been renamed to NotificationMessage. This message class can be used to deliver a notification (of type string) to a recipient. ViewModelBase constructor with IMessenger The ViewModelBase class now accepts an IMessenger parameter. If this constructor is used instead of the default empty constructor, the IMessenger passed as parameter will be used to broadcast a PropertyChangedMessage when the method RaisePropertyChanged<T>(string propertyName, T oldValue, T newValue, bool broadcast) is used. In the default ViewModelBase constructor is used, the Messenger.Default instance will be used instead. EventToCommand behavior The EventToCommand behavior has been added in V3. It can be used to bind any event of any FrameworkElement to any ICommand (for example a RelayCommand located in the ViewModel). More information about the EventToCommand behavior can be found here and here. Updated the project templates to remove the sample application The project template has been updated to remove the sample application that was created every time that a new MVVM Light application was created in Visual Studio or Blend. This makes the creation of a new application easier, because you don’t need to remove code before you can start writing code. Bug corrections Some bugs that were in Version 2 have been corrected: In some occasions, an exception could be thrown when a recipient was registered for a message at the same time as a message was received. New names for DLLs If you upgrade an existing installation, you will need to change the reference to the DLLs in C:\Program Files\Laurent Bugnion (GalaSoft)\Mvvm Light Toolkit\Binaries. The assemblies have been moved, and the versions for Silverlight 4 and for WPF4 have been renamed, to avoid some confusion. It is now easier to make sure that you are using the correct DLL. WPF3.5SP1, Silverlight 3 When using the DLLs, make sure that you use the correct versions. WPF4, Silverlight 4 When using the DLLs, make sure that you use the correct versions. Laurent Bugnion (GalaSoft) Subscribe | Twitter | Facebook | Flickr | LinkedIn

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What do you need to know to be a world-class master software developer? [closed]

- by glitch

I wanted to bring up this question to you folks and see what you think, hopefully advise me on the matter: let's say you had 30 years of learning and practicing software development in front of you, how would you dedicate your time so that you'd get the biggest bang for your buck. What would you both learn and work on to be a world-class software developer that would make a large impact on the industry and leave behind a legacy? I think that most great developers end up being both broad generalists and specialists in one-two areas of interest. I'm thinking Bill Joy, John Carmack, Linus Torvalds, K&R and so on. I'm thinking that perhaps one approach would be to break things down by categories and establish a base minimum of "software development" greatness. I'm thinking: Operating Systems: completely internalize the core concepts of OS, perhaps gain a lot of familiarity with an OSS one such as Linux. Anything from memory management to device drivers has to be complete second nature. Programming Languages: this is one of those topics that imho has to be fully grokked even if it might take many years. I don't think there's quite anything like going through the process of developing your own compiler, understanding language design trade-offs and so on. Programming Language Pragmatics is one of my favorite books actually, I think you want to have that internalized back to back, and that's just the start. You could go significantly deeper, but I think it's time well spent, because it's such a crucial building block. As a subset of that, you want to really understand the different programming paradigms out there. Imperative, declarative, logic, functional and so on. Anything from assembly to LISP should be at the very least comfortable to write in. Contexts: I believe one should have experience working in different contexts to truly be able to appreciate the trade-offs that are being made every day. Embedded, web development, mobile development, UX development, distributed, cloud computing and so on. Hardware: I'm somewhat conflicted about this one. I think you want some understanding of computer architecture at a low level, but I feel like the concepts that will truly matter will be slightly higher level, such as CPU caching / memory hierarchy, ILP, and so on. Networking: we live in a completely network-dependent era. Having a good understanding of the OSI model, knowing how the Web works, how HTTP works and so on is pretty much a pre-requisite these days. Distributed systems: once again, everything's distributed these days, it's getting progressively harder to ignore this reality. Slightly related, perhaps add solid understanding of how browsers work to that, since the world seems to be moving so much to interfacing with everything through a browser. Tools: Have a really broad toolset that you're familiar with, one that continuously expands throughout the years. Communication: I think being a great writer, effective communicator and a phenomenal team player is pretty much a prerequisite for a lot of a software developer's greatness. It can't be overstated. Software engineering: understanding the process of building software, team dynamics, the requirements of the business-side, all the pitfalls. You want to deeply understand where what you're writing fits from the market perspective. The better you understand all of this, the more of your work will actually see the daylight. This is really just a starting list, I'm confident that there's a ton of other material that you need to master. As I mentioned, you most likely end up specializing in a bunch of these areas as you go along, but I was trying to come up with a baseline. Any thoughts, suggestions and words of wisdom from the grizzled veterans out there who would like to share their thoughts and experiences with this? I'd really love to know what you think!

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iPhone SDK vs Windows Phone 7 Series SDK Challenge, Part 1: Hello World!

In this series, I will be taking sample applications from the iPhone SDK and implementing them on Windows Phone 7 Series. My goal is to do as much of an apples-to-apples comparison as I can. This series will be written to not only compare and contrast how easy or difficult it is to complete tasks on either platform, how many lines of code, etc., but Id also like it to be a way for iPhone developers to either get started on Windows Phone 7 Series development, or for developers in general to learn the platform. Heres my methodology: Run the iPhone SDK app in the iPhone Simulator to get a feel for what it does and how it works, without looking at the implementation Implement the equivalent functionality on Windows Phone 7 Series using Silverlight. Compare the two implementations based on complexity, functionality, lines of code, number of files, etc. Add some functionality to the Windows Phone 7 Series app that shows off a way to make the scenario more interesting or leverages an aspect of the platform, or uses a better design pattern to implement the functionality. You can download Microsoft Visual Studio 2010 Express for Windows Phone CTP here, and the Expression Blend 4 Beta here. Hello World! Of course no first post would be allowed if it didnt focus on the hello world scenario. The iPhone SDK follows that tradition with the Your First iPhone Application walkthrough. I will say that the developer documentation for iPhone is pretty good. There are plenty of walkthoughs and they break things down into nicely sized steps and do a good job of bringing the user along. As expected, this application is quite simple. It comprises of a text box, a label, and a button. When you push the button, the label changes to Hello plus the word you typed into the text box. Makes perfect sense for a starter application. Theres not much to this but it covers a few basic elements: Laying out basic UI Handling user input Hooking up events Formatting text So, lets get started building a similar app for Windows Phone 7 Series! Implementing the UI: UI in Silverlight (and therefore Windows Phone 7) is defined in XAML, which is a declarative XML language also used by WPF on the desktop. For anyone thats familiar with similar types of markup, its relatively straightforward to learn, but has a lot of power in it once you get it figured out. Well talk more about that. This UI is very simple. When I look at this, I note a couple of things: Elements are arranged vertically They are all centered So, lets create our Application and then start with the UI. Once you have the the VS 2010 Express for Windows Phone tool running, create a new Windows Phone Project, and call it Hello World: Once created, youll see the designer on one side and your XAML on the other: Now, we can create our UI in one of three ways: Use the designer in Visual Studio to drag and drop the components Use the designer in Expression Blend 4 to drag and drop the components Enter the XAML by hand in either of the above Well start with (1), then kind of move to (3) just for instructional value. To develop this UI in the designer: First, delete all of the markup between inside of the Grid element (LayoutRoot). You should be left with just this XAML for your MainPage.xaml (i shortened all the xmlns declarations below for brevity): 1: <phoneNavigation:PhoneApplicationPage 2: x:Class="HelloWorld.MainPage" 3: xmlns="...[snip]" 4: FontFamily="{StaticResource PhoneFontFamilyNormal}" 5: FontSize="{StaticResource PhoneFontSizeNormal}" 6: Foreground="{StaticResource PhoneForegroundBrush}"> 7: 8: <Grid x:Name="LayoutRoot" Background="{StaticResource PhoneBackgroundBrush}"> 9: 10: </Grid> 11: 12: </phoneNavigation:PhoneApplicationPage> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Well be adding XAML at line 9, so thats the important part. Now, Click on the center area of the phone surface Open the Toolbox and double click StackPanel Double click TextBox Double click TextBlock Double click Button That will create the necessary UI elements but they wont be arranged quite right. Well fix it in a second. Heres the XAML that we end up with: 1: <StackPanel Height="100" HorizontalAlignment="Left" Margin="10,10,0,0" Name="stackPanel1" VerticalAlignment="Top" Width="200"> 2: <TextBox Height="32" Name="textBox1" Text="TextBox" Width="100" /> 3: <TextBlock Height="23" Name="textBlock1" Text="TextBlock" /> 4: <Button Content="Button" Height="70" Name="button1" Width="160" /> 5: </StackPanel> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } The designer does its best at guessing what we want, but in this case we want things to be a bit simpler. So well just clean it up a bit. We want the items to be centered and we want them to have a little bit of a margin on either side, so heres what we end up with. Ive also made it match the values and style from the iPhone app: 1: <StackPanel Margin="10"> 2: <TextBox Name="textBox1" HorizontalAlignment="Stretch" Text="You" TextAlignment="Center"/> 3: <TextBlock Name="textBlock1" HorizontalAlignment="Center" Margin="0,100,0,0" Text="Hello You!" /> 4: <Button Name="button1" HorizontalAlignment="Center" Margin="0,150,0,0" Content="Hello"/> 5: </StackPanel> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Now lets take a look at what weve done there. Line 1: We removed all of the formatting from the StackPanel, except for Margin, as thats all we need. Since our parent element is a Grid, by default the StackPanel will be sized to fit in that space. The Margin says that we want to reserve 10 pixels on each side of the StackPanel. Line 2: Weve set the HorizontalAlignment of the TextBox to Stretch, which says that it should fill its parents size horizontally. We want to do this so the TextBox is always full-width. We also set TextAlignment to Center, to center the text. Line 3: In contrast to the TextBox above, we dont care how wide the TextBlock is, just so long as it is big enough for its text. Thatll happen automatically, so we just set its Horizontal alignment to Center. We also set a Margin above the TextBlock of 100 pixels to bump it down a bit, per the iPhone UI. Line 4: We do the same things here as in Line 3. Heres how the UI looks in the designer: Believe it or not, were almost done! Implementing the App Logic Now, we want the TextBlock to change its text when the Button is clicked. In the designer, double click the Button to be taken to the Event Handler for the Buttons Click event. In that event handler, we take the Text property from the TextBox, and format it into a string, then set it into the TextBlock. Thats it! 1: private void button1_Click(object sender, RoutedEventArgs e) 2: { 3: string name = textBox1.Text; 4: 5: // if there isn't a name set, just use "World" 6: if (String.IsNullOrEmpty(name)) 7: { 8: name = "World"; 9: } 10: 11: // set the value into the TextBlock 12: textBlock1.Text = String.Format("Hello {0}!", name); 13: 14: } .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } We use the String.Format() method to handle the formatting for us. Now all thats left is to test the app in the Windows Phone Emulator and verify it does what we think it does! And it does! Comparing against the iPhone Looking at the iPhone example, there are basically three things that you have to touch as the developer: 1) The UI in the Nib file 2) The app delegate 3) The view controller Counting lines is a bit tricky here, but to try to keep this even, Im going to only count lines of code that I could not have (or would not have) generated with the tooling. Meaning, Im not counting XAML and Im not counting operations that happen in the Nib file with the XCode designer tool. So in the case of the above, even though I modified the XAML, I could have done all of those operations using the visual designer tool. And normally I would have, but the XAML is more instructive (and less steps!). Im interested in things that I, as the developer have to figure out in code. Im also not counting lines that just have a curly brace on them, or lines that are generated for me (e.g. method names that are generated for me when I make a connection, etc.) So, by that count, heres what I get from the code listing for the iPhone app found here: HelloWorldAppDelegate.h: 6 HelloWorldAppDelegate.m: 12 MyViewController.h: 8 MyViewController.m: 18 Which gives me a grand total of about 44 lines of code on iPhone. I really do recommend looking at the iPhone code for a comparison to the above. Now, for the Windows Phone 7 Series application, the only code I typed was in the event handler above Main.Xaml.cs: 4 So a total of 4 lines of code on Windows Phone 7. And more importantly, the process is just A LOT simpler. For example, I was surprised that the User Interface Designer in XCode doesnt automatically create instance variables for me and wire them up to the corresponding elements. I assumed I wouldnt have to write this code myself (and risk getting it wrong!). I dont need to worry about view controllers or anything. I just write my code. This blog post up to this point has covered almost every aspect of this apps development in a few pages. The iPhone tutorial has 5 top level steps with 2-3 sub sections of each. Now, its worth pointing out that the iPhone development model uses the Model View Controller (MVC) pattern, which is a very flexible and powerful pattern that enforces proper separation of concerns. But its fairly complex and difficult to understand when you first walk up to it. Here at Microsoft weve dabbled in MVC a bit, with frameworks like MFC on Visual C++ and with the ASP.NET MVC framework now. Both are very powerful frameworks. But one of the reasons weve stayed away from MVC with client UI frameworks is that its difficult to tool. We havent seen the type of value that beats double click, write code! for the broad set of scenarios. Another thing to think about is how many of those lines of code were focused on my apps functionality?. Or, the converse of How many lines of code were boilerplate plumbing? In both examples, the actual number of functional code lines is similar. I count most of them in MyViewController.m, in the changeGreeting method. Its about 7 lines of code that do the work of taking the value from the TextBox and putting it into the label. Versus 4 on the Windows Phone 7 side. But, unfortunately, on iPhone I still have to write that other 37 lines of code, just to get there. 10% of the code, 1 file instead of 4, its just much simpler. Making Some Tweaks It turns out, I can actually do this application with ZERO lines of code, if Im willing to change the spec a bit. The data binding functionality in Silverlight is incredibly powerful. And what I can do is databind the TextBoxs value directly to the TextBlock. Take some time looking at this XAML below. Youll see that I have added another nested StackPanel and two more TextBlocks. Why? Because thats how I build that string, and the nested StackPanel will lay things out Horizontally for me, as specified by the Orientation property. 1: <StackPanel Margin="10"> 2: <TextBox Name="textBox1" HorizontalAlignment="Stretch" Text="You" TextAlignment="Center"/> 3: <StackPanel Orientation="Horizontal" HorizontalAlignment="Center" Margin="0,100,0,0" > 4: <TextBlock Text="Hello " /> 5: <TextBlock Name="textBlock1" Text="{Binding ElementName=textBox1, Path=Text}" /> 6: <TextBlock Text="!" /> 7: </StackPanel> 8: <Button Name="button1" HorizontalAlignment="Center" Margin="0,150,0,0" Content="Hello" Click="button1_Click" /> 9: </StackPanel> .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } Now, the real action is there in the bolded TextBlock.Text property: Text="{Binding ElementName=textBox1, Path=Text}" .csharpcode, .csharpcode pre { font-size: small; color: black; font-family: consolas, "Courier New", courier, monospace; background-color: #ffffff; /*white-space: pre;*/ } .csharpcode pre { margin: 0em; } .csharpcode .rem { color: #008000; } .csharpcode .kwrd { color: #0000ff; } .csharpcode .str { color: #006080; } .csharpcode .op { color: #0000c0; } .csharpcode .preproc { color: #cc6633; } .csharpcode .asp { background-color: #ffff00; } .csharpcode .html { color: #800000; } .csharpcode .attr { color: #ff0000; } .csharpcode .alt { background-color: #f4f4f4; width: 100%; margin: 0em; } .csharpcode .lnum { color: #606060; } That does all the heavy lifting. It sets up a databinding between the TextBox.Text property on textBox1 and the TextBlock.Text property on textBlock1. As I change the text of the TextBox, the label updates automatically. In fact, I dont even need the button any more, so I could get rid of that altogether. And no button means no event handler. No event handler means no C# code at all. Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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How to Buy an SD Card: Speed Classes, Sizes, and Capacities Explained

- by Chris Hoffman

Memory cards are used in digital cameras, music players, smartphones, tablets, and even laptops. But not all SD cards are created equal — there are different speed classes, physical sizes, and capacities to consider. Different devices require different types of SD cards. Here are the differences you’ll need to keep in mind when picking out the right SD card for your device. Speed Class In a nutshell, not all SD cards offer the same speeds. This matters for some tasks more than it matters for others. For example, if you’re a professional photographer taking photos in rapid succession on a DSLR camera saving them in high-resolution RAW format, you’ll want a fast SD card so your camera can save them as fast as possible. A fast SD card is also important if you want to record high-resolution video and save it directly to the SD card. If you’re just taking a few photos on a typical consumer camera or you’re just using an SD card to store some media files on your smartphone, the speed isn’t as important. Manufacturers use “speed classes” to measure an SD card’s speed. The SD Association that defines the SD card standard doesn’t actually define the exact speeds associated with these classes, but they do provide guidelines. There are four different speed classes — 10, 8, 4, and 2. 10 is the fastest, while 2 is the slowest. Class 2 is suitable for standard definition video recording, while classes 4 and 6 are suitable for high-definition video recording. Class 10 is suitable for “full HD video recording” and “HD still consecutive recording.” There are also two Ultra High Speed (UHS) speed classes, but they’re more expensive and are designed for professional use. UHS cards are designed for devices that support UHS. Here are the associated logos, in order from slowest to fastest: You’ll probably be okay with a class 4 or 6 card for typical use in a digital camera, smartphone, or tablet. Class 10 cards are ideal if you’re shooting high-resolution videos or RAW photos. Class 2 cards are a bit on the slow side these days, so you may want to avoid them for all but the cheapest digital cameras. Even a cheap smartphone can record HD video, after all. An SD card’s speed class is identified on the SD card itself. You’ll also see the speed class on the online store listing or on the card’s packaging when purchasing it. For example, in the below photo, the middle SD card is speed class 4, while the two other cards are speed class 6. If you see no speed class symbol, you have a class 0 SD card. These cards were designed and produced before the speed class rating system was introduced. They may be slower than even a class 2 card. Physical Size Different devices use different sizes of SD cards. You’ll find standard-size CD cards, miniSD cards, and microSD cards. Standard SD cards are the largest, although they’re still very small. They measure 32x24x2.1 mm and weigh just two grams. Most consumer digital cameras for sale today still use standard SD cards. They have the standard “cut corner” design. miniSD cards are smaller than standard SD cards, measuring 21.5x20x1.4 mm and weighing about 0.8 grams. This is the least common size today. miniSD cards were designed to be especially small for mobile phones, but we now have a smaller size. microSD cards are the smallest size of SD card, measuring 15x11x1 mm and weighing just 0.25 grams. These cards are used in most cell phones and smartphones that support SD cards. They’re also used in many other devices, such as tablets. SD cards will only fit into marching slots. You can’t plug a microSD card into a standard SD card slot — it won’t fit. However, you can purchase an adapter that allows you to plug a smaller SD card into a larger SD card’s form and fit it into the appropriate slot. Capacity Like USB flash drives, hard drives, solid-state drives, and other storage media, different SD cards can have different amounts of storage. But the differences between SD card capacities don’t stop there. Standard SDSC (SD) cards are 1 MB to 2 GB in size, or perhaps 4 GB in size — although 4 GB is non-standard. The SDHC standard was created later, and allows cards 2 GB to 32 GB in size. SDXC is a more recent standard that allows cards 32 GB to 2 TB in size. You’ll need a device that supports SDHC or SDXC cards to use them. At this point, the vast majority of devices should support SDHC. In fact, the SD cards you have are probably SDHC cards. SDXC is newer and less common. When buying an SD card, you’ll need to buy the right speed class, size, and capacity for your needs. Be sure to check what your device supports and consider what speed and capacity you’ll actually need. Image Credit: Ryosuke SEKIDO on Flickr, Clive Darra on Flickr, Steven Depolo on Flickr

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Puppet inheritance of parametrized classes

- by paweloque

I have a situation in puppet where I want to inherit from a parametrized class: class base ($basepath) { ... } class extends_base ($ext_param) inherits base { ... } Now trying to instantiate the extends_base class I get the following error message: Must pass basepath to Class[Base] However, I don't see a way how to pass the basepath parameter to the Base class.. I tried to pass the param in the Class[Extends_base] definition, puppet doesn't like this either.

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System.InvalidOperationException compiling ASP.NET app on Mono

- by Radu094

This is the error I get when I start my ASP.NET application in Mono: System.InvalidOperationException: The process must exit before getting the requested information. at System.Diagnostics.Process.get_ExitCode () [0x00044] in /usr/src/mono-2.6.3/mcs/class/System/System.Diagnostics/Process.cs:149 at (wrapper remoting-invoke-with-check) System.Diagnostics.Process:get_ExitCode () at Mono.CSharp.CSharpCodeCompiler.CompileFromFileBatch (System.CodeDom.Compiler.CompilerParameters options, System.String[] fileNames) [0x001ee] in /usr/src/mono-2.6.3/mcs/class/System/Microsoft.CSharp/CSharpCodeCompiler.cs:267 at Mono.CSharp.CSharpCodeCompiler.CompileAssemblyFromFileBatch (System.CodeDom.Compiler.CompilerParameters options, System.String[] fileNames) [0x00011] in /usr/src/mono-2.6.3/mcs/class/System/Microsoft.CSharp/CSharpCodeCompiler.cs:156 at System.CodeDom.Compiler.CodeDomProvider.CompileAssemblyFromFile (System.CodeDom.Compiler.CompilerParameters options, System.String[] fileNames) [0x00014] in /usr/src/mono-2.6.3/mcs/class/System/System.CodeDom.Compiler/CodeDomProvider.cs:119 at System.Web.Compilation.AssemblyBuilder.BuildAssembly (System.Web.VirtualPath virtualPath, System.CodeDom.Compiler.CompilerParameters options) [0x0022f] in /usr/src/mono-2.6.3/mcs/class/System.Web/System.Web.Compilation/AssemblyBuilder.cs:804 at System.Web.Compilation.AssemblyBuilder.BuildAssembly (System.Web.VirtualPath virtualPath) [0x00000] in /usr/src/mono-2.6.3/mcs/class/System.Web/System.Web.Compilation/AssemblyBuilder.cs:730 at System.Web.Compilation.BuildManager.GenerateAssembly (System.Web.Compilation.AssemblyBuilder abuilder, System.Web.Compilation.BuildProviderGroup group, System.Web.VirtualPath vp, Boolean debug) [0x00254] in /usr/src/mono-2.6.3/mcs/class/System.Web/System.Web.Compilation/BuildManager.cs:624 at System.Web.Compilation.BuildManager.BuildInner (System.Web.VirtualPath vp, Boolean debug) [0x0011c] in /usr/src/mono-2.6.3/mcs/class/System.Web/System.Web.Compilation/BuildManager.cs:411 at System.Web.Compilation.BuildManager.Build (System.Web.VirtualPath vp) [0x00050] in /usr/src/mono-2.6.3/mcs/class/System.Web/System.Web.Compilation/BuildManager.cs:356 at System.Web.Compilation.BuildManager.GetCompiledType (System.Web.VirtualPath virtualPath) [0x0003a] in /usr/src/mono-2.6.3/mcs/class/System.Web/System.Web.Compilation/BuildManager.cs:803 at System.Web.Compilation.BuildManager.CreateInstanceFromVirtualPath (System.Web.VirtualPath virtualPath, System.Type requiredBaseType) [0x0000c] in /usr/src/mono-2.6.3/mcs/class/System.Web/System.Web.Compilation/BuildManager.cs:500 at System.Web.UI.PageParser.GetCompiledPageInstance (System.String virtualPath, System.String inputFile, System.Web.HttpContext context) [0x0001c] in /usr/src/mono-2.6.3/mcs/class/System.Web/System.Web.UI/PageParser.cs:161 at System.Web.UI.PageHandlerFactory.GetHandler (System.Web.HttpContext context, System.String requestType, System.String url, System.String path) [0x00000] in /usr/src/mono-2.6.3/mcs/class/System.Web/System.Web.UI/PageHandlerFactory.cs:45 at System.Web.HttpApplication.GetHandler (System.Web.HttpContext context, System.String url, Boolean ignoreContextHandler) [0x00055] in /usr/src/mono-2.6.3/mcs/class/System.Web/System.Web/HttpApplication.cs:1643 at System.Web.HttpApplication.GetHandler (System.Web.HttpContext context, System.String url) [0x00000] in /usr/src/mono-2.6.3/mcs/class/System.Web/System.Web/HttpApplication.cs:1624 at System.Web.HttpApplication+<Pipeline>c__Iterator2.MoveNext () [0x0075f] in /usr/src/mono-2.6.3/mcs/class/System.Web/System.Web/HttpApplication.cs:1259 I checked the source code indicated by the stacktrace, namely :CSharpCodeCompiler.cs:267 mcs.WaitForExit(); result.NativeCompilerReturnValue = mcs.ExitCode; //this throws the exception I have no ideea if this is a bug in Mono, or if my App is doing something it shoudn't. A simple "Hello World" application indicates that Mono is properly installed and working, It is just my app that is causing this exception to be thrown. Hoping some enlighted minds have more on the issue

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ASP.NET. MVC2. Entity Framework. Cannot pass primary key value back from view to [HttpPost]

- by Paul Connolly

I pass a ViewModel (which contains a "Person" object) from the "EditPerson" controller action into the view. When posted back from the view, the ActionResult receives all of the Person properties except the ID (which it says is zero instead of say its real integer) Can anyone tell me why? The controllers look like this: public ActionResult EditPerson(int personID) { var personToEdit = repository.GetPerson(personID); FormationViewModel vm = new FormationViewModel(); vm.Person = personToEdit; return View(vm); } [HttpPost] public ActionResult EditPerson(FormationViewModel model) <<Passes in all properties except ID { // Persistence code } The View looks like this: <%@ Page Title="" Language="C#" MasterPageFile="~/Views/Shared/Site.Master" Inherits="System.Web.Mvc.ViewPage<Afp.Models.Formation.FormationViewModel>" %> <% using (Html.BeginForm()) {% <%= Html.ValidationSummary(true) % <fieldset> <legend>Fields</legend> <div class="editor-label"> <%= Html.LabelFor(model => model.Person.Title) %> </div> <div class="editor-field"> <%= Html.TextBoxFor(model => model.Person.Title) %> <%= Html.ValidationMessageFor(model => model.Person.Title) %> </div> <div class="editor-label"> <%= Html.LabelFor(model => model.Person.Forename)%> </div> <div class="editor-field"> <%= Html.TextBoxFor(model => model.Person.Forename)%> <%= Html.ValidationMessageFor(model => model.Person.Forename)%> </div> <div class="editor-label"> <%= Html.LabelFor(model => model.Person.Surname)%> </div> <div class="editor-field"> <%= Html.TextBoxFor(model => model.Person.Surname)%> <%= Html.ValidationMessageFor(model => model.Person.Surname)%> </div> <div class="editor-label"> <%= Html.LabelFor(model => model.DOB) %> </div> <div class="editor-field"> <%= Html.TextBoxFor(model => model.DOB, String.Format("{0:g}", Model.DOB)) <%= Html.ValidationMessageFor(model => model.DOB) %> </div>--%> <div class="editor-label"> <%= Html.LabelFor(model => model.Person.Nationality)%> </div> <div class="editor-field"> <%= Html.TextBoxFor(model => model.Person.Nationality)%> <%= Html.ValidationMessageFor(model => model.Person.Nationality)%> </div> <div class="editor-label"> <%= Html.LabelFor(model => model.Person.Occupation)%> </div> <div class="editor-field"> <%= Html.TextBoxFor(model => model.Person.Occupation)%> <%= Html.ValidationMessageFor(model => model.Person.Occupation)%> </div> <div class="editor-label"> <%= Html.LabelFor(model => model.Person.CountryOfResidence)%> </div> <div class="editor-field"> <%= Html.TextBoxFor(model => model.Person.CountryOfResidence)%> <%= Html.ValidationMessageFor(model => model.Person.CountryOfResidence)%> </div> <div class="editor-label"> <%= Html.LabelFor(model => model.Person.PreviousNameForename)%> </div> <div class="editor-field"> <%= Html.TextBoxFor(model => model.Person.PreviousNameForename)%> <%= Html.ValidationMessageFor(model => model.Person.PreviousNameForename)%> </div> <div class="editor-label"> <%= Html.LabelFor(model => model.Person.PreviousSurname)%> </div> <div class="editor-field"> <%= Html.TextBoxFor(model => model.Person.PreviousSurname)%> <%= Html.ValidationMessageFor(model => model.Person.PreviousSurname)%> </div> <div class="editor-label"> <%= Html.LabelFor(model => model.Person.Email)%> </div> <div class="editor-field"> <%= Html.TextBoxFor(model => model.Person.Email)%> <%= Html.ValidationMessageFor(model => model.Person.Email)%> </div> <p> <input type="submit" value="Save" /> </p> </fieldset> <% } % And the Person class looks like: [MetadataType(typeof(Person_Validation))] public partial class Person { public Person() { } } [Bind(Exclude = "ID")] public class Person_Validation { public int ID { get; private set; } public string Title { get; set; } public string Forename { get; set; } public string Surname { get; set; } public System.DateTime DOB { get; set; } public string Nationality { get; set; } public string Occupation { get; set; } public string CountryOfResidence { get; set; } public string PreviousNameForename { get; set; } public string PreviousSurname { get; set; } public string Email { get; set; } } And ViewModel: public class FormationViewModel { public Company Company { get; set; } public Address RegisteredAddress { get; set; } public Person Person { get; set; } public PersonType PersonType { get; set; } public int CurrentStep { get; set; } } }

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`gem install mongrel` fails with ruby 1.9.1

- by atlantis

I initiated myself into rails development yesterday. I installed ruby 1.9.1, rubygems and rails. Running gem install mongrel worked fine and ostensibly installed mongrel too. I am slightly puzzled because: script/server starts webrick by default which mongrel returns nothing locate mongrel returns lots of entries like /Developer/SDKs/MacOSX10.5.sdk/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1 /Developer/SDKs/MacOSX10.5.sdk/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/lib /Developer/SDKs/MacOSX10.5.sdk/System/Library/Frameworks/Ruby.framework/Versions/1.8/usr/lib/ruby/gems/1.8/gems/mongrel-1.0.1/lib/mongrel . . . /usr/local/bin/mongrel_rails /usr/local/lib/ruby/gems/1.9.1/cache/mongrel-1.1.5.gem /usr/local/lib/ruby/gems/1.9.1/doc/actionpack-2.3.2/rdoc/files/lib/action_controller/vendor/rack-1_0/rack/handler/evented_mongrel_rb.html /usr/local/lib/ruby/gems/1.9.1/doc/actionpack-2.3.2/rdoc/files/lib/action_controller/vendor/rack-1_0/rack/handler/mongrel_rb.html /usr/local/lib/ruby/gems/1.9.1/doc/actionpack-2.3.2/rdoc/files/lib/action_controller/vendor/rack-1_0/rack/handler/swiftiplied_mongrel_rb.html /usr/local/lib/ruby/gems/1.9.1/gems/actionpack-2.3.2/lib/action_controller/vendor/rack-1.0/rack/handler/evented_mongrel.rb /usr/local/lib/ruby/gems/1.9.1/gems/actionpack-2.3.2/lib/action_controller/vendor/rack-1.0/rack/handler/mongrel.rb /usr/local/lib/ruby/gems/1.9.1/gems/actionpack-2.3.2/lib/action_controller/vendor/rack-1.0/rack/handler/swiftiplied_mongrel.rb /usr/local/lib/ruby/gems/1.9.1/gems/mongrel-1.1.5 . . . Does look like I have mongrel installed (both the default installation and my custom install). So why doesn't which mongrel return something. Also trying to reinstall mongrel using gem install mongrel returns throws its own set of exceptions: Building native extensions. This could take a while... ERROR: Error installing mongrel: ERROR: Failed to build gem native extension. /usr/local/bin/ruby extconf.rb install mongrel checking for main() in -lc... yes creating Makefile make gcc -I. -I/usr/local/include/ruby-1.9.1/i386-darwin9.7.0 -I/usr/local/include/ruby-1.9.1/ruby/backward -I/usr/local/include/ruby-1.9.1 -I. -D_XOPEN_SOURCE -D_DARWIN_C_SOURCE -fno-common -D_XOPEN_SOURCE=1 -O2 -g -Wall -Wno-parentheses -fno-common -pipe -fno-common -o http11.o -c http11.c http11.c: In function 'http_field': http11.c:77: error: 'struct RString' has no member named 'ptr' http11.c:77: error: 'struct RString' has no member named 'len' http11.c:77: warning: left-hand operand of comma expression has no effect http11.c:77: warning: statement with no effect http11.c: In function 'header_done': http11.c:172: error: 'struct RString' has no member named 'ptr' http11.c:174: error: 'struct RString' has no member named 'ptr' http11.c:176: error: 'struct RString' has no member named 'ptr' http11.c:177: error: 'struct RString' has no member named 'len' http11.c: In function 'HttpParser_execute': http11.c:298: error: 'struct RString' has no member named 'ptr' http11.c:299: error: 'struct RString' has no member named 'len' make: *** [http11.o] Error 1

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