How to implement a partial class with static object definition in C#

Question

//Found the solution... The problem was in fact that I have an array of register filled on creation (contructor method) and that array wasn't instanciated.

To make it short, I've been too noob to even put a break point in the constructor to see if .Net handled a first chance exception.

Thanks again for all the repliers. You have been really helpful. :) Sorry again for my noobness

What have I learned today : -You never know how .net will merge your partial class -Be more aware of first chance exceptions

//STATE CHANGE 2012/01/30 17:00 or so Sorry, I narrowed on the wrong problem. The problem explained here doesn't seem to be caused by the code provided therefore this question no longer needs to exist. Thanks to the repliers!

//DEPRECATED, CLOSED ... W/E

I have a device which can be contacted by various registry such 0x01, 0x02, 0x03... Also, I work in a development environment and the application I produce are oriented for our own environment in a small compagny.

To turn these registry into object I have chosen, a long time ago, to make a class which have it's constructor private to create it's own and only instance (As I understand, multi-ton design pattern).

Since there's a lot of registry now and the class file is getting huge I want to split it into parts : The property/function definitions and the multi-ton objects.

When I try to use this ex: Register.cs :

namespace DeviceManagement.Register
{
    public partial class Register
    {
       public int id { get; private set; }
       public string foo { get; private set; }
       public string bar { get; private set; }

       protected Register(RegisterEnum id, string foo, string bar)
       {
          this.id = (int)id;
          this.foo = foo;
          this.bar = bar;
       }
    }
}

Register.enum.cs :

namespace DeviceManagement.Register
{
    public partial class Register
    {
       protected enum RegisterEnum
       {
          reg1 = 0x01,
          reg2 = 0x02 //and so on
       };
    }
}

Register.const.cs :

namespace DeviceManagement.Register
{
    public partial class Register
    {
       public static readonly Register reg1 = 
          new Register(RegisterEnum.reg1,"foo1","bar1");
       public static readonly Register reg2 = 
          new Register(RegisterEnum.reg2,"foo2","bar2");
       //there is plenty more
    }
}

I intended to use it like

namespace DeviceManagement
{
   class SomeClassA
   {
       public void doThisOnDevice(Device device)
       {
          device.doSomeStuffOn(Register.Register.reg1, SomeCommonlyUsedStrategy);
       }
   }
}

Here's a test I did :

namespace DeviceManagement
{
   class SomeClassA
   {
       public void testIfNull()
       {
          if(Register.Register.reg1 == null)
             MessageBox.Show("It is null");
       }
   }
}

The compilator, intellisense doesn't throw any error/warning but, when I run my project, the Register objects are never instanciated. Altough, I don't have that issue when all this code is in the same class (not partial) and obviously in the same file.

I'm kind of lost, please help me.

When you say the Register objects are never instanciated, does that mean that Register.reg1 is null inside doThisOnDevice(...) ? — Julian
– Julian, Commented Jan 30, 2012 at 20:48
Other than some compilation errors, There is no error in your code. I think your code here does not reflect the real code. — L.B
– L.B, Commented Jan 30, 2012 at 20:59
@Nailuj, Yes it is null and if I set a break point on any declaration/instanciation line. It never stops there. Register.Register.reg1 is null when I try to call the like in doThisOnDevice(...) — Francis Gagnon
– Francis Gagnon, Commented Jan 30, 2012 at 21:08
@L.B indeed it is not my real code but a shorten sample of it with stuff renamed. Other than context errors I don't see either why it wouldn't work. — Francis Gagnon
– Francis Gagnon, Commented Jan 30, 2012 at 21:11
@L.B You are right, I tested this code into another project /w the renaming and all and it does work fine. — Francis Gagnon
– Francis Gagnon, Commented Jan 30, 2012 at 21:21

WestDiscGolf · Accepted Answer · 2012-01-30 21:28:23Z

1

For starters you don't need to break it out into a partial class to have it over multiple files. If you want to lump it together then you can put it in a different sub namespace in separate files, anyway ...

It looks like a namespace issue, as you need to have Register.Register.reg1 to access the static const.

EDIT

Ok, so from the feedback and re-reading the question a few more times I get the feeling that the current design probably won't quite work all in the same class definition. I think you maybe trying to force something into some thing which won't go.

So, why not try something like this:

namespace DeviceManagement.Register
{
    public class Register
    {
        public RegisterType Type { get; private set; }
        public string Foo { get; private set; }
        public string Bar { get; private set;  }

        public Register(RegisterType type, string foo, string bar)
        {
            Type = type;
            Foo = foo;
            Bar = bar;
        }
    }

    public enum RegisterType
    {
        reg1 = 0x01,
        reg2 = 0x02 //and so on   
    }

    public static class RegisterFactory
    {
        private static readonly Dictionary<RegisterType, Register> _dictionary = new Dictionary<RegisterType, Register>
                                                                     {
                                                                         { RegisterType.reg1, new Register(RegisterType.reg1, "foo", "bar") },
                                                                         { RegisterType.reg2, new Register(RegisterType.reg2, "foo2", "bar2") }
                                                                     };

        public static Register GetRegister(RegisterType type)
        {
            return _dictionary[type];
        }
    }
}

And consume the register:

public class SomeClassA
{
    public void DoThisOnDevice(Device device)
    {
        device.DoSomeStuffOn(RegisterFactory.GetRegister(RegisterType.reg1), SomeCommonlyUsedStrategy);
    }
}

You could then take it a step further and load in the registry details from a configuration file which parses it on start up of your application to, you could then choose the registry type to work on from your UI etc.

Hope I've not got the wrong end of the stick.

edited Jan 30, 2012 at 21:28

answered Jan 30, 2012 at 20:52

WestDiscGolf

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5 Comments

Francis Gagnon Over a year ago

Thanks for you quick reply I edited my question to correct that error.

Francis Gagnon Over a year ago

In fact I already had that feature. But I have been requested to hardcode those. Since this application can be shipped to clients even if it is not designed to and my boss didn't like the fact that if the user isn't the administrator reading and writing file can be harder. and we don't want to have to do tech support for : How to use your computer. Well anyway thanks for you reply, you got it right it would work. Altough i don't like the idea of iterating through a dictionary each time i want to access a register.

WestDiscGolf Over a year ago

You won't be iterating through the dictionary each time, its a key value lookup. The dictionary will be initialised when the application first tried to access the dictionary, it will then be there for the duration of the application running. I understand about the not wanting the details to be in a config file :-)

Francis Gagnon Over a year ago

Key value lookup seems a lot like an iteration to me but well. I did some more tests on my side and it seems that the code I posted here was quite fine. it also doesn't seem to be the source of my problem even if when I merge the files back toguether i no longer encounter the problem. Your help is really appreciated tho :)

Francis Gagnon Over a year ago

The problem was in fact that I have an array of register filled on creation (contructor method) and that array wasn't instanciated. To make it short, I've been too noob to even put a break point in the constructor to see if .Net handled a first chance exception. Thanks again for all the repliers. You have been really helpful. :) Sorry again for my noobness What have I learned today : -You never know how .net will merge your partial class -Be more aware of first chance exceptions

Olivier Jacot-Descombes · Accepted Answer · 2012-01-30 21:37:40Z

0

I copy pasted your code and it works fine for me.

My advice is to use the Class View of Visual Studio. Here you can easily see if all the partial classes are defined within the same namespace and with the exactly same class name. If not, too many namespaces or classes will appear.

answered Jan 30, 2012 at 21:37

Olivier Jacot-Descombes

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1 Comment

Francis Gagnon Over a year ago

Yes I figured that my sample code work. I try to figure out why my copy paste of my code converted to sample work and not the original. Thanks for your reply

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