As a developer my initial plan was to develop something running on Raspberry Pi. Unfortunately being a .NET developer and playing around with Microsoft stack all the time, my arsenal for Linux development is very limited. Before I master Python, I wanted to run small applications using Mono. This would be a good chance to see how smoothly .NET programs can run independent from the platform.

So I booted my Raspberry Pi with a Raspbian image (hard-float ABI). And installed Mono runtime and MonoDevelop IDE.

sudo apt-get update
sudo apt-get install mono-runtime
sudo apt-get install monodevelop

Launched MonoDevelop eagerly to write my first Hello World program on Raspberry Pi and boom! I got the following error:

The good old “Object reference not set to an instance of an object” exception!

After searching around I found out that Mono doesn’t run on Raspbian image and it requires an image with “soft-float ABI“. Turns out soft-float version runs floating point operations using software instead of FPU (Floating Point Unit). Therefore soft-float version it is slower than Raspbian. I quickly downloaded the soft-float image and tried to boot it up again. This time I couldn’t even see the login screen. It got stuck at a stage saying “Waiting for /dev to be fully populated” After some time it timed out and started giving some errors.

Having no idea what’s going on, consulted Google again and found out other people had the same problem. The proposed solution was to replace start.elf with the one from the hard-float image. I tried running it with the replaced elf file but got the same result. I’ve been doing all these experiments on my new Raspberry Pi which is 512MB. Having failed where others seemed to succeed, I put the blame on the hardware I’m using and decided to try the same image with the old Pi. The result was promising: I could boot the Pi with the soft-float version finally. I installed the Mono runtime and MonoDevelop again but looks like MonoDevelop is above Pi’s paygrade! It was excruciatingly slow that I decided to create the sample project on my desktop PC and carry it over with a USB flash drive. Mounted the flash drive using the following commands (replace tosh with directory name you want and make sure you’re mounting the correct device.)

sudo mkdir /media/tosh
sudo mount -t vfat -o uid=pi,gid=pi /dev/sda1 /media/tosh/

Here comes the moment of truth. I changed the directory to the copied files and ran the exe file. Here’s the output:

The screen glares but at the bottom of the screen you can see the glowing (by all means) phrase: Hello World! Of course, this is just the beginning. I’ll see how compatible and reliable Mono framework is after I deploy more complex applications on Raspberry Pi.

Today I came across an interesting namespace collision. I’m writing a library to wrap a 3rd party API. So without getting into specifics I’ll try to illustrate the situation on a sample piece of code. Let’s say we have a class called Test in TestNamespace namespace.

namespace TestNamespace
{
    public class Test
    {
        public static void StaticMethod()
        {
        }
    }
}

and the calling class is something like this:

namespace DifferentNamespace.TestNamespace
{
    class Program
    {
        static void Main(string[] args)
        {
            TestNamespace.Test.StaticMethod();
        }
     }
}

This code doesn’t compile because compiler thinks “TestNamespace.Test” is actually “DifferentNamespace.TestNamespace.Test”.

Adding a using directive doesn’t help either. As it has the same namespace as the subnamespace of the calling class it always resolves to calling class’s namespace. The solution is using “global” namespace.

namespace DifferentNamespace.TestNamespace
{
    using TestNamespace = global::TestNamespace;

    class Program
    {
        static void Main(string[] args)
        {
            TestNamespace.Test.StaticMethod();
        }
    }
}

By explicitly specifying which TestNamespace we are referring to we resolve the conflict. One thing to keep in mind is that we have to define it inside the namespace. If we used it outside the DifferentNamespace.TestNamespace, then inside the namespace TestNamespace would still mean “DifferentNamespace.TestNamespace”

Before this incident, I never had to use the global keyword. Probably the best way to avoid this is by naming conventions but sometimes you may not be able to change the namespace name. You can break lots of things if there are dependant parties on that code. So every now and then this tip may come in handy, just like it did to me in this instance.

Some code snippets are extremely helpful like prop for properties and ctor for constructors. But writing a method is always taking relatively long time as there is no snippet for methods. For good reason I guess as there are all different shapes and colours of methods but I think a snippet can save some time for simple methods. So I decided to create my own snippets. Here’s how to do it in 3 simple steps:

STEP 01: Download the snippet designer from here: http://snippetdesigner.codeplex.com Install and restart visual studio. From File –> New menu select Code Snippet file type.

STEP 02: Save the output of the snippet designer under code snippets folder %USERPROFILE%\Documents\Visual Studio 2012\Code Snippets\Visual C#\My Code Snippets which looks like this

<?xml version="1.0" encoding="utf-8"?>
<CodeSnippets xmlns="http://schemas.microsoft.com/VisualStudio/2005/CodeSnippet">
  <CodeSnippet Format="1.0.0">
    <Header>
      <SnippetTypes>
        <SnippetType>Expansion</SnippetType>
      </SnippetTypes>
      <Title>MethodVoid</Title>
      <Author>dummy</Author>
      <Description>
      </Description>
      <HelpUrl>
      </HelpUrl>
      <Shortcut>method_void</Shortcut>
    </Header>
    <Snippet>
      <Declarations>
        <Literal Editable="false">
          <ID>Method1</ID>
          <ToolTip></ToolTip>
          <Default>
          </Default>
          <Function>
          </Function>
        </Literal>
      </Declarations>
      <Code Language="csharp"><![CDATA[public void MyMetHod()
    {
    }]]></Code>
    </Snippet>
  </CodeSnippet>
</CodeSnippets>

STEP 03: Restart Visual Studio for the changes to take effect. I created a few snippets for simple methods returning primitive types. Depending on your needs you can choose the optimum number of snippets. I especially like using the test method snippet which looks like this:

Another great feature about this tool is you can export a selected text block as a snippet. All you have to do is right-click and select Export as Snippet, make the final touches in the editor and save.