Greg Robinson's Blog : .NET

VB.NET is not OOP?

gregarobinson — Wed, 30 Sep 2009 16:09:00 GMT

I started a discussion on this subject after hearing it more than once from a recruiter.

Recruiters, please read this discussion, learn and educate your clients.

Technical Interview Questions

gregarobinson — Thu, 24 Sep 2009 15:47:00 GMT

I have been on some recent technical interviews for Tech Lead and/or Architect Roles. I am keeping track of the questions asked and will post them here. The answers you see are mostly copy/paste from a Google search, with a mix of my own thoughts. Feel free to jump in with your own questions and/or answers.

1. define encapsulation

a. Data /Information hiding, hiding; objects do not reveal their attributes and behaviors. All interaction with an object should be done thru it’s interface.

b. Storing data and functions in a single unit (class) is encapsulation. Data cannot be accessible to the outside world and only those functions which are stored in the class can access it.

c. The purpose is to achieve potential for change: the internal mechanisms of the component can be improved without impact on other components, or the component can be replaced with a different one that supports the same public interface. Encapsulation also protects the integrity of the component, by preventing users from setting the internal data of the component into an invalid or inconsistent state. Another benefit of encapsulation is that it reduces system complexity and thus increases robustness, by limiting the interdependencies between software components.

2. define abstraction

a. the act of representing essential features without including the background details or explanations.

b. reduce and factor out details so that one can focus on a few concepts at a time.

3. define garbage collection and what is meant by generational GC

a. The .NET Framework's garbage collector manages the allocation and release of memory for your application. Each time you use the new operator to create an object, the runtime allocates memory for the object from the managed heap. As long as address space is available in the managed heap, the runtime continues to allocate space for new objects. However, memory is not infinite. Eventually the garbage collector must perform a collection in order to free some memory. The garbage collector's optimizing engine determines the best time to perform a collection, based upon the allocations being made. When the garbage collector performs a collection, it checks for objects in the managed heap that are no longer being used by the application and performs the necessary operations to reclaim their memory.

b. The garbage collector keeps track of objects that have Finalize methods, using an internal structure called the finalization queue. Each time your application creates an object that has a Finalize method, the garbage collector places an entry in the finalization queue that points to that object. The finalization queue contains entries for all the objects in the managed heap that need to have their finalization code called before the garbage collector can reclaim their memory.

c. Generational collectors group objects by age and collect younger objects more often than older objects. When initialized, the managed heap contains no objects. All new objects added to the heap can be said to be in generation 0, until the heap gets filled up which invokes garbage collection. As most objects are short-lived, only a small percentage of young objects are likely to survive their first collection. Once an object survives the first garbage collection, it gets promoted to generation 1.Newer objects after GC can then be said to be in generation 0.The garbage collector gets invoked next only when the sub-heap of generation 0 gets filled up. All objects in generation 1 that survive get compacted and promoted to generation 2. All survivors in generation 0 also get compacted and promoted to generation 1. Generation 0 then contains no objects, but all newer objects after GC go into generation 0. Thus, as objects "mature" (survive multiple garbage collections) in their current generation, they are moved to the next older generation. Generation 2 is the maximum generation supported by the runtime's garbage collector. When future collections occur, any surviving objects currently in generation 2 simply stay in generation 2. Thus, dividing the heap into generations of objects and collecting and compacting younger generation objects improves the efficiency of the basic underlying garbage collection algorithm by reclaiming a significant amount of space from the heap and also being faster than if the collector had examined the objects in all generations.

i. The GC maintains lists of managed objects arranged in "generations." A generation is a measure of the relative lifetime of the objects in memory. The generation number indicates to which generation an object belongs. Recently created objects are stored in lower generations compared to those created earlier in the application's life cycle. Longer-lived objects get promoted to higher generations. Because applications tend to create many short-lived objects compared to relatively few long-lived objects, the GC runs much more frequently to clean up objects in the lower generations than in the higher ones.

4. define disposing in .NET

a. Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.

5. Define the difference between finalize and dispose in .NET

a. In general, the Dispose pattern is used to release unmanaged resources in a timely fashion. This allows you to do this in a deterministic fashion- in other words, you have control over when they are released. The Object.Finalize method is also used for the purpose of releasing resources - but it is non-deterministic. You have no control over when it will be called by the GC. Further, implementing a Finalize method can have an adverse affect on the performance of the GC because it takes two passes of the GC to collect objects that override Finalize. So, in general, if you are using objects that manage unmanaged resources, such as database connections, you implement IDisposable AND override Finalize. This way, your covered if the client fails to call Dispose - you know that your resources will then be released when the object is GC'd. Of course, one you call Dispose - you don't need the finalize method to be called by the GC and suffer an unnecessary performance hit.

6. xml tags and attributes

7. define soa

a. Service Oriented Architecture: putting enterprise functionality that rarely or never changes in the enterprise into a service that all enterprise applications can call into; typically a web service

b. SOA is the practice of sequestering the core business functions into independent services that don’t change frequently. These services are glorified functions that are called by one or more presentation programs. The presentation programs are volatile bits of software that present data to, and accept data from, various users.

c. At the highest level, SOA is nothing more (and nothing less) than separating changeable elements from unchangeable elements

d. SOA is not about any particular technology. Rather it is a design philosophy that decouples well heeled business functions from volatile processes and presentation

8. define soap

9. define serialization

a. the process of converting the state of an object into a form that can be persisted or transported. The complement of serialization is deserialization, which converts a stream into an object. Together, these processes allow data to be easily stored and transferred.

b. NET Framework features two serializing technologies:

i. Binary serialization preserves type fidelity, which is useful for preserving the state of an object between different invocations of an application. For example, you can share an object between different applications by serializing it to the Clipboard. You can serialize an object to a stream, to a disk, to memory, over the network, and so forth. Remoting uses serialization to pass objects "by value" from one computer or application domain to another.

ii. XML serialization serializes only public properties and fields and does not preserve type fidelity. This is useful when you want to provide or consume data without restricting the application that uses the data. Because XML is an open standard, it is an attractive choice for sharing data across the Web. SOAP is likewise an open standard, which makes it an attractive choice.

10. define DTO

a. Data Transfer Object; could be custom Business Objects, DataSets

11. Define marshalling

a. The process of gathering data and transforming it into a standard format before it is transmitted over a network so that the data can transcend network boundaries. In order for an object to be moved around a network, it must be converted into a data stream that corresponds with the packet structure of the network transfer protocol. This conversion is known as data marshalling. Data pieces are collected in a message buffer before they are marshaled. When the data is transmitted, the receiving computer converts the marshaled data back into an object.

b. Data marshalling is required when passing the output parameters of a program written in one language as input to a program written in another language.

12. Define interactions with business folks, selling your idea, coaching them, etc

13. define design patterns, give an example of 2

14. define Polymorphism

a. “Many Forms”. The ability of a derived class to perform its own implementation of a parents method thus re-defining the method. It’s the ability to hide alternative implementations behind a common interface.

15. learn more about current web services, messaging, patterns, etc

16. What does the finalize method do and when to use it

a. allows an object to clean up its unmanaged resources properly when the garbage collector reclaims the memory used by the object

b. By default, the Finalize method does nothing. If you want the garbage collector to perform cleanup operations on your object before it reclaims the object's memory, you must override the Finalize method in your class

c. The unmanaged resources must be explicitly released once the application has finished using them. .Net Framework provides the Object.Finalize method: a method that the garbage collector must run on the object to clean up its unmanaged resources, prior to reclaiming the memory used up by the object. Since Finalize method does nothing, by default, this method must be overridden if explicit cleanup is required.

d. Finalize provides a backup to prevent resources from permanently leaking if the programmer fails to call Dispose

17. What is reflection and when would one use it

a. The ability to discover the composition of a type (e.g., class, interface, structure, enumeration, or delegate) at runtime.

b. The classes in the System.Reflection namespace, together with System.Type, allow you to obtain information about loaded assemblies and the types defined within them, such as classes, interfaces, and value types. You can also use reflection to create type instances at run time, and to invoke and access them.

18. Define AppDomains

19. Define Clustered Indexes in SQL Server

.NET Software Developer needed

gregarobinson — Mon, 19 Jan 2009 18:58:00 GMT

I know there are a lot of folks looking for work so I plan to post what I know:

Charlottesville, VA

Permanent Hire

Not remote/offsite

".NET Software Developer

We're looking to add a web developer to our software development group. You'll work in a development team where flexibility, creativity, and continuous learning form the modus operandi. Successful Web Developer Candidates have:

4+ years experience with Microsoft web technologies, including ASP.NET, VB.NET, and MS SQL Server

Understanding of the full software development lifecycle

Proficiency in Object Oriented and N-tier architecture design principles

Interface implementation (HTML/DHTML/CSS/AJAX)

Deep knowledge of XML (a must)

Knowledge of XSL/XSLT (a plus)

Desire to thrive in a creative team environment

The ability to quickly learn and effectively apply new technologies and concepts"

Web development in the .NET world has gotten a lot more interesting in the last couple of years

gregarobinson — Wed, 31 Dec 2008 16:13:00 GMT

A good and quick read on the 3 options by Davy Brion

Creating a windows service in .Net

gregarobinson — Wed, 31 Dec 2008 13:27:00 GMT

I was going to get around to blogging about this, eventually. I came across this read this morning which does a nice job, so I am now spared!

OSLO = 42

gregarobinson — Tue, 30 Dec 2008 17:57:00 GMT

A good post from Head in the Cloud.

Developing Visual Studio in the snow

gregarobinson — Wed, 24 Dec 2008 13:20:00 GMT

I thought this was a cool pic

Migrate sites, lists and libraries between SharePoint servers with views, versions, user-info, web parts, permissions and metadata.

gregarobinson — Wed, 24 Dec 2008 12:35:00 GMT

My client asked me to figure out how to copy a SharePoint site from one server to another server. In my clients case they have an internal SharePoint site that they would like to copy to one of their clients/customers servers.

Metalogix offers content migration and archiving solutions. Thanks for sharing this with me Mark. I took a look at their solutions and they look good, and will certainly do the job.

I am a figure it out for yourself kind of person so I dug into the SharePoint documentation.

Microsoft Office SharePoint Server 2007 includes the Stsadm tool for command-line administration of Office SharePoint Server 2007 servers and sites. Stsadm is located at the following path on the drive where SharePoint Products and Technologies is installed: C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\BIN. You must be an administrator on the local computer to use Stsadm.

Stsadm provides a method for performing the Office SharePoint Server 2007 administration tasks at the command line or by using batch files or scripts. For more on the Stsadm tool see this site.

Two of the operations, Export and Import, can be used to move a Sharepoint site and its contents from one server to another. The Export operation exports site and subsite data from a Microsoft Office SharePoint Server 2007 installation and the Import operation imports site and subsite data from a Microsoft Office SharePoint Server 2007 installation. Using the combination of two one can package up a Sharepoint site, with its contents, and move it to another server.

The stsadm tool is located here: C:\Program Files\Common Files\Microsoft Shared\web server extensions\12\BIN. Open cmd.exe to use this tool. First, start with the export using the stsadmn tool with the following parameters:

stsadm -o export -url http://therurl/theexistingsite -includeusersecurity -nofilecompression -filename test

Executing this will create a folder under the BIN folder named “test”. The test folder will contain .dat, .log and .xml files. I cannot state this for sure, as I have not been able to document it, but it appears each .dat files represents a document (a PDF in my clients case).

I used the nofilecompression parameter as I was seeing low disk space errors while testing this on a development server. This will enable file compression in the import package. The import package is stored in the folder specified by the -filename parameter. It is recommended to use this parameter for performance reasons. If compression is enabled, it can increase the import process by approximately 30%.

The includeusersecurity parameter preserves the user security settings. I am not sure at this point if this is needed when creating an import package that will be executed outside of a client's network as the user settings on a clients server will most likley differ from the internal settings.

Now, to import simply replace the Export operation above with the Import operation. You also need to replace "url http://therurl/theexistingsite with" url http://therurl/thenewsite, pointing to the url for the site you are importing to.

So far so good, this process seems to work.

MGrammer

gregarobinson — Mon, 22 Dec 2008 17:05:00 GMT

Man, where have I been. I was catching up on my RSS feeds this morning and tripped on this.

Book recommendations?

gregarobinson — Mon, 22 Dec 2008 13:07:00 GMT

I get this question often, what books should I read to become a better developer? Not just 'how to code better' either. We are talking full life cycle here, start to finish (is there ever a finish?).

I have been too lazy to put a list together. Today, I saw this list. It's pretty much every book I have read, I am reading or plan to read. Replace C# with VB.NET and that's me in a nutshell.

The Future of .NET Reflector

gregarobinson — Thu, 21 Aug 2008 18:00:00 GMT

FYI, from

Lutz Roeder

"After more than eight years of working on .NET Reflector, I have decided it is time to move on and explore some new opportunities.

I have reached an agreement to have Red Gate Software continue the development of .NET Reflector. Red Gate has a lot of experience creating development tools for both .NET and SQL Server. They have the resources necessary to work on new features, and Reflector fits nicely with other .NET tools the company offers.

Red Gate will continue to provide the free community version and is looking for your feedback and ideas for future versions.

For news and updates on Reflector, sign up for the .NET Developer’s Newsletter from Red Gate. To find out more about the agreement, see the interview on Simple Talk."

VB6 to .NET

gregarobinson — Wed, 27 Feb 2008 13:02:00 GMT

Beth Massi did a nice webcast on migrating from VB6 to .NET. Beth does a nice job letting us VBers know about the new thinks coming and how to use them. Keep an eye on her blog.

To WPF or not

gregarobinson — Tue, 26 Feb 2008 19:23:00 GMT

WPF is one of those latest and greatest things I need to dig into...yeah, I know, we all have the same 24 hours in a day.

Here is a nice post on chosing between WPF or WinForms. Wow, it feels like yesterday that we just started using WinForms and now we are saying "consider something else". Time files in this industry.

.NET 2.0 SP1 shipped

gregarobinson — Wed, 13 Feb 2008 15:22:00 GMT

In case you missed it. .NET 2.0 SP1 shipped recently. This one caused some issues for us, which took us a day or two to resolve. Hopefully there are some things in there that help us.

We are on VS 2008

gregarobinson — Fri, 25 Jan 2008 15:03:00 GMT

We made the conversion to VS 2008 in our current Release code base today. I'll keep you posted on how it goes. We are hoping to pick up some speed.