Posts

Fooled by the Activator !!!

It was interesting to know that a custom exception, say an exception class derived from System.ApplicationException, thrown while creating an instance of a type using Activator.CreateInstance does not get caught in its appropriate exception handler, instead gets caught in the global exception handler catch(Exception ex), if provided. Any exception raised while creating an instance of the loaded type is wrapped inside a new exception object as InnerException by Activator.CreateInstance.

I was fooled that there was some problem with the image generation for quite some time, and then very lately inspected the members of the exception caught and found my exception object wrapped as InnerException.

Properties C# 2.0 – Not Elegant Enough

Prior to .NET 2.0, there wasn’t the facility in C# to opt the visibility level for the get and set property or indexers. And i take my comment in my previous post that C# does not provide the facility of having different visibility levels for the get and set accessors. While that is partly correct, it is no more in C# 2.0.

And obviously it isn’t in the easy and elegant way. Take a look at this code snippet:-

Singularity – Safety & Speed !!!

I read about this interesting thing somewhere in MSDN.

There are two types of programming or programming languages. The good old C/C++ kind called the unsafe programming languages, and the other is the safe programming type which we realised very much after advent of Java/C#. And there has always been debate about safety and speed. And neither of the two has won.

So Microsoft is doing a research on a new operating system called Singularity which is written in a safe programming language [C#]. Although there are parts in the OS, especially the kernel, that uses unsafe code, it stills uses the safe C#. So in the Singularity environment, every program that runs is safe. And the environment as such is reinventing from the hardware layers up and above.

out, ref and InvokeMember !!!

When I was working on the .NET reflection extravaganza thing that I explained in my previous column, i learnt one another interesting thing, that is about the Type.InvokeMember. How will pass out or ref parameters for the method invoked using Type.InvokeMember ? If you are going to invoke a method with the prototype

int DoSomething(string someString, int someInt);

then you would use InvokeMember like this:-

object obj = someType.InvokeMember(“DoSomething”,
        BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance,
        null,
        this,
        new object[] {“Largest Integer”, 1});

or use some variables in the new object[] {…}. But what do you with the args if DoSomething takes out or ref parameters ?

.NET Reflection Extravanganza !!!

Over the past few weeks, I have been involved with this module that got the best of both worlds - .NET and I, 😁.

Ok, this was the problem. We have a COM server, let us name it Server. I had to write an assembly in C#, let us call it Bridge, that will listen to all of the events fired by the Server and perform an action Action. To keep that Action simple, let us assume we have to log them to the database. But the Server fires hundreds of events, and it is not wise to write up static event handlers for all of them. Also, if more events are (ever) added in the future, the Bridge should be able to support it without code changes.

The twist in the game was that this was a brown + green field development project. That demanded a wise solution - learn from the past and better the future.

Where is my C++ ?

I have been using C# for quite some time now, and that too VS 2005. I see that Programming Pain at a macro level has boiled down to thinking than coding. Though it might be an advantage on one side, I feel I have become lazy. Since I am a programmer from the C++ world, it was very easy to become lazy. The small and handy applications that I write for myself in C++, I am writing them in C#. Even now I am a great disciple of C++. And even though C++/CLI is out there, and I work a small amount of it in my project, I am getting inclined to C#. More ...

Infinite .NET Languages !!!

Though I knew that there are quite a few languages for the .NET platform, I came to know when surfing today that there are many well beyond my knowledge, most surprisingly like the COBOL.

Check it out @ http://www.dotnetpowered.com/languages.aspx

Implementing COM OutOfProc Servers in C# .NET !!!

Had to implement our COM OOP Server project in .NET, and I found this solution from the internet after a great deal of search, but unfortunately the whole idea was ruled out, and we wrapped it as a .NET assembly. This is worth knowing.

Step 1

Implement IClassFactory in a class in .NET. Use the following definition for IClassFactory.

namespace COM
{
   static class Guids
   {
      public const string IClassFactory = "00000001-0000-0000-C000-000000000046";
      public const string IUnknown = "00000000-0000-0000-C000-000000000046";
   }

   ///
   /// IClassFactory declaration
   ///
   [ComImport(), InterfaceType(ComInterfaceType.InterfaceIsIUnknown), Guid(COM.Guids.IClassFactory)]
   internal interface IClassFactory
   {
      [PreserveSig]
      int CreateInstance(IntPtr pUnkOuter, ref Guid riid, out IntPtr ppvObject);
      [PreserveSig]
      int LockServer(bool fLock);
   }
}

Step 2

Non-conventional Window Shapes [I love C#] !!!

I am not a UI guy. More specifically, I love to work with UIs. I think (only) a UI can give a better picture of the system in a multitasking environment unlike Unix. I do not say I hate Unix. And I do not like to work on UIs ie program on UIs cuz I do not know much. But have always wanted to create a non-conventional window, say an elliptical one. .NET made things like that very easy for guys like me. Look at the code below for creating a ellipitcal window. More ...

Serialization and Exceptions !!!

I am just like Alice in Wonderland, and not yet got out of the wonders of the .NET framework, C# and the VS 2003(5) IDE. I thought that the serialization is all not my thing until I do something big in C#. I had written this custom exception class in my project that has 3 processes connected by .NET Remoting Infrastructure. I throw my custom exception for a scenario but all I got was some other exception: More ...