Tuesday, January 28, 2014

ERROR [IM014] [Microsoft][ODBC Driver Manager] The specified DSN contains an architecture mismatch between the Driver and Application

I was trying to pull data from AS400s’ DB2 database from a SQL Server Analysis Services project. Once I run my SSAS project, I was getting this error “ERROR [IM014] [Microsoft][ODBC Driver Manager] The specified DSN contains an architecture mismatch between the Driver and Application”. But to my surprise from my ADO.NET Source, when I previewed my query I was getting data as expected.

My DSN was 32-bit and I was using 32-bit BIDS in my 64-bit computer.

Picture1
Project Properties Window
Since data is retrieved when I click on Preview inside my ADO.NET Source, I was sure there is nothing wrong in the DSN. So there should be something wrong with the project. Went to project Properties and under “Debugging” changed “Run64BitRuntime” to false.

No more errors and it was perfectly working.

Happy Coding.

Regards,
Jaliya

Monday, January 20, 2014

Visual C# Technical Guru - December 2013

Became the Visual C# Technical Guru for the last month of the year 2013. There was not much of a competition this time, only two contestants including myself.

The TechNet Guru Awards celebrate the technical articles on Microsoft TechNet.

Post in WikiNinjas Official Blog,
Picture
Visual C# Technical Guru - December 2013
Happy Coding.

Regards,
Jaliya

Tuesday, January 14, 2014

Lock Statement in C#

Lock statement can be really useful when you are writing multi threaded applications. Basically what lock statement does is, it monitors and prevents some particular blocks of code from being accessed simultaneously by multiple threads.

It's always good to go by an example. First I am creating a very simple multi threaded application without any lock statements. I am having a class there named “MyClass” which will have a single method.
public class MyClass
{
    public void MyMethodWithoutLock()
    {
        Thread.Sleep(5000);
        Console.WriteLine("Without Lock " + DateTime.Now);
    }
}
Inside the above method, let’s assume that I am doing some time consuming work and then I am printing out a message with the current time.

Inside the Main method, I am going to create a object of “MyClass” and I am going to call the “MyMethodWithoutLock” from some different threads.
class Program
{
    static void Main(string[] args)
    {
        MyClass oMyClass = new MyClass();
        List<Thread> threads = new List<Thread>();
 
        for (int i = 0; i < 5; i++)
        {
            Thread t = new Thread(oMyClass.MyMethodWithoutLock);
            threads.Add(t);
        }
 
        foreach (Thread t in threads)
        {
            t.Start();
        }
 
        Console.WriteLine(DateTime.Now);
    }
}
Here there is nothing complex, just some very simple multi threading. I have created a object of "MyClass" and created a variable to hold list of threads. Then I have added 5 threads to threads list which will call the “MyMethodWithoutLock” of my one and only object “oMyClass”. Finally I am starting all the threads at once and printing out the current time. Please note that in my Main method, I have created only a single object of “MyClass”

So the output will be as follows.
Pic1
Without Lock
As you can see after starting the treads at 11:35:01, all the threads has completed calling “MyMethodWithoutLock” simultaneously at 11:35:06. So the point here is all threads have been calling “MyMethodWithoutLock” at the same time which is a prefect concurrency.

Now let’s say, I have a scenario where I have two methods. One method should be called simultaneously and the other should not be called simultaneously. For this I can use the lock statement and let’s see how.

Hers is my modified class.
public class MyClass
{
    private Object thisLock = new Object();
 
    public void MyMethodWithoutLock()
    {
        Thread.Sleep(5000);
        Console.WriteLine("Without Lock " + DateTime.Now);
    }
 
    public void MyMethodWithLock()
    {
        lock (thisLock)
        {
            Thread.Sleep(5000);
            Console.WriteLine("With Lock " + DateTime.Now);
        }
    }
}
Inside Main, I will have some threads as previous, the only difference is, my threads will be calling both these two methods as below.
class Program
{
    static void Main(string[] args)
    {
        MyClass oMyClass = new MyClass();
        List<Thread> threads = new List<Thread>();
 
        for (int i = 0; i < 5; i++)
        {
            Thread t = new Thread(new ThreadStart(() =>
            {
                oMyClass.MyMethodWithoutLock();
                oMyClass.MyMethodWithLock();
            }));
            threads.Add(t);
        }
 
        foreach (Thread t in threads)
        {
            t.Start();
        }
 
        Console.WriteLine(DateTime.Now);
    }
}
Now the output will be as follows.
Pic2
With Lock
If you can see here, my set of threads has called “MyMethodWithoutLock” method simultaneously. But “MyMethodWithLock” method has been called by only one single thread at a time. After one thread completed executing “MyMethodWithLock” method, then another thread came in and has accessed “MyMethodWithLock”.

Now if you have read the above well, I have mentioned I have created only a single object of “MyClass”. Let’s modify the above code where I am creating several objects of “MyClass” and each thread will be accessing separate objects’ methods.
class Program
{
    static void Main(string[] args)
    {
        List<Thread> threads = new List<Thread>();
 
        for (int i = 0; i < 5; i++)
        {
            Thread t = new Thread(new ThreadStart(() =>
            {
                MyClass oMyClass = new MyClass();
                oMyClass.MyMethodWithoutLock();
                oMyClass.MyMethodWithLock();
            }));
            threads.Add(t);
        }
 
        foreach (Thread t in threads)
        {
            t.Start();
        }
 
        Console.WriteLine(DateTime.Now);
    }
}
So the output will be as follows.
Pic3
With Lock Different Objects
Now here what has happened is both the methods has been called simultaneously back again. This explains the very basic concept of the lock statement. That is lock will only be blocking some code from accessing multiple threads only when the code belongs to same object. If the threads are accessing same method of different objects and still you want to block some code from multi thread access, if you use lock statement, basically it’s not going to help you.

For more information,
   lock Statement (C# Reference)
   Thread Synchronization

I am uploading the sample to my SkyDrive, do enjoy.


So hope this helps. Appreciate your all feedback.

Happy Coding.

Regards,
Jaliya

Monday, January 13, 2014

Microsoft Visual Studio Has Tweeted One Of My Wikis’

Microsoft Visual Studio has tweeted one of my wikis’. I was really surprised and felt so happy to see this tweet.
Untitled1
Microsoft Visual Studio has tweeted one of my wikis
Here is my wiki which was tweeted by @VisualStudio
   Visual C#: Thread.Sleep vs. Task.Delay

Happy Coding.

Regards,
Jaliya

Monday, January 6, 2014

Changing Entity Framework default connection factory from LocalDb to Microsoft SQL Server

When you create a project let’s say a Console Application and add Entity Framework, as you know EF will modify the existing app.config file by adding some EF relevant configurations (If you are creating a Web Application, EF will modify the web.config file.).

Now let’s say you are using Code First and adding some data. But you might be wondering where you have mentioned the connection string etc.. EF maintains these configurations in the configuration file and after EF5, it uses LocalDb as the defaultConnectionFactory. Previously it was using SQL Express.

Something extra, if you are wondering why use LocalDb, it’s because of this. Since SQL Express is the free version of Microsoft SQL Server and most developers that target SQL Server, tend to use SQL Express in their development machines. But with LocalDb they no longer have to install and manage a full instance of SQL Express, as the same T-SQL language, programming surface and client-side providers are provided with LocalDb.

So getting back to the topic, as I mentioned before, the app/web.config will be holding this defaultConnectionFactory setting for EF.
<entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.LocalDbConnectionFactory, EntityFramework">
      <parameters>
        <parameter value="v11.0" />
      </parameters>
    </defaultConnectionFactory>
    <providers>
      <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
    </providers>
</entityFramework>
Here you can see the defaultConnectionFactory is set to LocalDbConnectionFactory. Under the parameters, you can find the LocalDb version. For example, v11.0 represents SQL Server 2012.

Now let’s say you want to change the defaultConnectionFactory to a SQL Server instance. For that you will have to change the configuration as follows.
<entityFramework>
    <defaultConnectionFactory type="System.Data.Entity.Infrastructure.SqlConnectionFactory, EntityFramework">
      <parameters>
        <parameter value="Data Source=.;Integrated Security=True" />
      </parameters>
    </defaultConnectionFactory>
    <providers>
      <provider invariantName="System.Data.SqlClient" type="System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer" />
    </providers>
</entityFramework>
From now onwards, Entity Framework will use SQL Server as the defaultConnectionFactory for that particular application.

Something important to add here, with the release of EF6, it has introduced a new feature which is Code-Based Configuration. Using Code-Based Configuration you can mention the defaultConnectionFactory too. But the config file takes precedence over Code-Based configuration. In other words, if a configuration option is set in both code and in the config file, then the setting in the config file is used.

Happy Coding.

Regards,
Jaliya

Friday, January 3, 2014

Session : Lap Around Entity Framework at Sri Lanka .NET Forum

Yesterday conducted a session at Sri Lanka .NET Forum.



I have uploaded the slide deck and demo projects to my SkyDrive. Do check it out.



Happy Coding.

Regards,
Jaliya

Wednesday, January 1, 2014

Received Microsoft MVP Award for Visual C#

This is going to be my first post in this new year 2014.

Received the Microsoft Most Valuable Professional (MVP) Award for Visual C# and this is my first time. Feeling so great and I definitely will be keeping my contributions towards Visual C# technical community in every possible way.
MVPLogo
Microsoft Most Valuable Professional (MVP)
Thanks a lot Fiqri Ismail, Wellington Perera and Joy Rathnayake for everything. And Thank you much Microsoft. Really Means a lot.

Happy Coding.

Regards,
Jaliya