Re: Shortcut classes in another project - C# Discussion Boards

Wayne Gaylard4-Oct-11 21:27

Wayne Gaylard

4-Oct-11 21:27

The class library is compiled into a dynamic link library (dll), which is then referenced by the silverlight application. This gives the silverlight app the ability to use classes and interfaces defined in the class library project. So to use the both, you need to first compile the library project, and then add a reference to the library project in the silverlight project, using the 'add reference' link in project explorer of Visual Studio.

Hope this helps

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Shameel4-Oct-11 23:44

Shameel

4-Oct-11 23:44

In Visual Studio's 'Add Existing Item' dialog box, the 'Add' button has a drop down option called 'Add As Link' that does the job. It does not copy the file to the project folder, it just creates a shortcut to the actual file. So, the file can be shared with multiple project. This is a very dirty thing to do. Ideally, you should abstract common code into a separate class library.

mehrdadc485-Oct-11 0:02

mehrdadc48

5-Oct-11 0:02

thank you Shameel

Best wishes

Pete O'Hanlon5-Oct-11 0:11

5-Oct-11 0:11

Ideally is the word, except if you want to share code between two different versions of the CLR. This is the method that you are pretty much forced to do if you want the same code to work between WP7, Silverlight and WPF.

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Shameel5-Oct-11 0:25

Shameel

5-Oct-11 0:25

As long as you share files across same kind of projects that are targeted for different platforms, you are fine. But if you share file with projects of different nature, changing the file in one project may render the other project not compile at all (and trying to fix it may make the other project not compile). And that is something really dirty.

Pete O'Hanlon5-Oct-11 0:28

5-Oct-11 0:28

Indeed, but as I say, sometimes it's necessary. Welcome to the world of the professional WPF/Silverlight developer.

Forgive your enemies - it messes with their heads

"Mind bleach! Send me mind bleach!" - Nagy Vilmos

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Super Lloyd5-Oct-11 2:51

Super Lloyd

5-Oct-11 2:51

BTW, there is a new way! Smile | :)

http://visualstudiogallery.msdn.microsoft.com/b0e0b5e9-e138-410b-ad10-00cb3caf4981[^]

Although.. more convenient but more restrictive....

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_________________________________________________________
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Pete O'Hanlon5-Oct-11 3:00

Class inheritance, forcing new classes to implement certain functions

5-Oct-11 3:00

Looks good. Nice find. Thumbs Up | :thumbsup:

Forgive your enemies - it messes with their heads

"Mind bleach! Send me mind bleach!" - Nagy Vilmos

My blog | My articles | MoXAML PowerToys | Mole 2010 - debugging made easier - my favourite utility

ExoticmE4-Oct-11 9:07

Re: Class inheritance, forcing new classes to implement certain functions

4-Oct-11 9:07

Ok so i'm messing around with a few things, specifically interfaces.

Say I have a class 'Cat' with its base as 'Animal' Animal has a method in it like so

public virtual void Walk()
{
    // Do walking stuff
}

So Cat would override it with:

public override void Walk()
{
    // Do cat specific walking stuff
}

Simple right?

Here's my question though, is there a way to force cat to override the base Walk() method? So if another developer added a Dog class they would be forced to implement their own Walk method (even if it was just base.Walk()) ?

So interfaces kind of solves this, this is what i've tried

Cat : Animal : Interface
Animal has to implement the Walk method, but Cat doesn't

Cat : Animal, Interface
Cat has to implement the Walk method, but if the developer doesn't add or forgets the ',Interface' then it will 'break' it.

can someone give me some pointer as to go about this ?

Thanks.

harold aptroot4-Oct-11 9:14

harold aptroot

4-Oct-11 9:14

Sort of, you can make the method abstract, then it will have to implemented somehow. It could just throw a NotImplementedException though.

Re: Class inheritance, forcing new classes to implement certain functions

ExoticmE4-Oct-11 9:30

Re: Class inheritance, forcing new classes to implement certain functions

4-Oct-11 9:30

Using an abstract method in the base Animal class prevents you from doing base.Walk() because it has no implementation.

harold aptroot4-Oct-11 9:48

harold aptroot

4-Oct-11 9:48

Yes, but you could call it baseWalk without the dot.. or something less silly.

Message Removed

4-Oct-11 9:27

N_tro_P

4-Oct-11 9:27

Message Removed

Re: Class inheritance, forcing new classes to implement certain functions

dan!sh 4-Oct-11 9:32

dan!sh

4-Oct-11 9:32

Collin Jasnoch wrote:
not virtual. That is for overloading

Virtual is not for overloading. You do not need any special keyword overload. Both virtual and abstract are for overriding. Abstract, is a forced one while virtual is not.

"The worst code you'll come across is code you wrote last year.", wizardzz[^]

Re: Class inheritance, forcing new classes to implement certain functions

ExoticmE4-Oct-11 9:52

Re: Class inheritance, forcing new classes to implement certain functions

4-Oct-11 9:52

Interfaces cannot have any implementation, which is what I want

Ian Shlasko4-Oct-11 9:45

Ian Shlasko

4-Oct-11 9:45

Well, abstract will force the subclass to implement, but that prevents you from having a base implementation.

You could do this with a pair of methods...

public void Walk()
{
  // Do walking stuff
  WalkInternal();
}

protected abstract void WalkInternal();

This way, the subclass is forced to implement WalkInternal(), but all external calls would go to the base class's Walk() (Which can't be overridden).

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Re: Class inheritance, forcing new classes to implement certain functions

Pete O'Hanlon4-Oct-11 10:19

Re: Class inheritance, forcing new classes to implement certain functions

4-Oct-11 10:19

When I need this type of functionality, I normally implement an abstract On method that the sub classes have to override. Here's an example:

public abstract class Animal
{
  public void Walk()
  {
    Console.WriteLine("Starting the legs off now...");
    OnWalk();
  }

  protected abstract void OnWalk();
}

Forgive your enemies - it messes with their heads

"Mind bleach! Send me mind bleach!" - Nagy Vilmos

My blog | My articles | MoXAML PowerToys | Mole 2010 - debugging made easier - my favourite utility

jschell4-Oct-11 10:53

jschell

4-Oct-11 10:53

Member 8209737 wrote:
can someone give me some pointer as to go about this ?

In general it isn't usually worth time trying to get someone else to do the 'right' thing.

For example even if you force it one can still throw an exception or just call the base method (whether that is right or wrong.)

One uses interfaces and abstract classes not to force others to do the correct thing but rather to implement functionality that would otherwise be difficult, hard, impossible or obscure via some other methodology. If done correctly. If not done correctly then the design if flawed anyways so implementation details become meaningless.

One uses unit tests, system tests, etc to insure that correct functionality is implemented.

Re: Class inheritance, forcing new classes to implement certain functions

Eddy Vluggen4-Oct-11 12:43

Eddy Vluggen

4-Oct-11 12:43

Member 8209737 wrote:
can someone give me some pointer as to go about this ?

Does it have to be on the class level, or would it be alright to have it at the object-level (say, an event[^]?)

class SomeAnimalClass
{
    public event EventHandler IsWalkin;

    protected virtual void OnWalk()
    {
        Console.WriteLine("Doing walking stuff for " + this.GetType().Name);

        EventHandler isWalkin = IsWalkin;
        if (isWalkin != null)
        {
            isWalkin(this, EventArgs.Empty);
        }
        else
            throw new NotImplementedException("DoWalk isn't implemented in " + this.GetType().Name);
    }

    public void StartWalkin()
    {
        // point in code that's calling the custom Walk-method;
        OnWalk();
    }
}
class Cat: SomeAnimalClass { }
class Dawg: SomeAnimalClass { }

class Program
{
    static void Main(string[] args)
    {
        SomeAnimalClass animal = new Cat();
        animal.IsWalkin += (o, s) => 
            Console.WriteLine("specific walking stuff for this animal of type " + animal.GetType().Name);
        animal.StartWalkin();

        SomeAnimalClass otherAnimal = new Dawg();
        try
        {
            otherAnimal.StartWalkin();
        }
        catch (NotImplementedException nie)
        {
            Console.WriteLine(nie.Message);
        }
        Console.ReadKey();
    }
}

Output;

XML

Doing walking stuff for Cat
specific walking stuff for this animal of type Cat
Doing walking stuff for Dawg
DoWalk isn't implemented in Dawg

Reposted, seems I did something wrong as the prev. post doesn't show up

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Re: Class inheritance, forcing new classes to implement certain functions

ExoticmE4-Oct-11 16:38