How to invoke base class methods instead overridens [modified] - C# Discussion Boards

#realJSOP17-Dec-08 0:23

17-Dec-08 0:23

According to what you've described, this is what I think is happening.

When you click the button in question, a function in another class is executed first.

If this post was helpful, be sure to vote it as such.

"Why don't you tie a kerosene-soaked rag around your ankles so the ants won't climb up and eat your candy ass..." - Dale Earnhardt, 1997
-----
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Re: Button?

Member 441328317-Dec-08 0:50

Member 4413283

17-Dec-08 0:50

u didn't clear in web or windows
check their click event and the class u use

2d Closet Designer

willy200516-Dec-08 23:27

willy2005

16-Dec-08 23:27

Hi.
I'm a spanish developer, i need to implement a 2D Closet designer very similar to this: http://www.ikea.com/ms/es_ES/rooms_ideas/pax_step_by_step_08/index.html
The system must do this:
1. drag items with texture, from the menu to a design area.
2. drop in the area in function of the properties, for example:
- Object_A, can drop only in the base of the closet.
- The size of the Object_B is from point A to the point of collision in the near object
- We can put the Object_C, only from top to bottom (move restricted in x direction).
3. The user can edit the position and the size of any object in any time.

Did any of you know resources (tutorials, examples, templates, libraries, plug-ins...) that can help me to finish saving time?
I have a little problem of time.
Thank you.

Hi.
I'm a spanish developer, i need to implement a 2D Closet designer very similar to this: http://www.ikea.com/ms/es_ES/rooms_ideas/pax_step_by_step_08/index.html
The system must do this:
1. drag items with texture, from the menu to a design area.
2. drop in the area in function of the properties, for example:
- Object_A, can drop only in the base of the closet.
- The size of the Object_B is from point A to the point of collision in the near object
- We can put the Object_C, only from top to bottom (move restricted in x direction).
3. The user can edit the position and the size of any object in any time.

Did any of you know resources (tutorials, examples, templates, libraries, plug-ins...) that can help me to finish saving time?
I have a little problem of time.
Thank you.

Re: 2d Closet Designer

#realJSOP17-Dec-08 0:21

#realJSOP

17-Dec-08 0:21

Wow - a re-post in the same message.

Re: 2d Closet Designer

Tom Deketelaere17-Dec-08 0:26

Tom Deketelaere

17-Dec-08 0:26

And in a cross post as well(c# and vb forums)

Re: 2d Closet Designer

willy200517-Dec-08 23:41

willy2005

17-Dec-08 23:41

Re: 2d Closet Designer

Eddy Vluggen17-Dec-08 0:28

Eddy Vluggen

17-Dec-08 0:28

Also posted in the VB.NET forum;
http://www.codeproject.com/script/Forums/View.aspx?fid=1646&msg=2847743

A good resource would be TestDriven.com. It will help you finishing in time, by making sure that you do not go overtime by creating bugs Smile | :)

I are troll Smile | :)

How to invoke base class methods instead overridens [modified]

El'Cachubrey16-Dec-08 23:20

El'Cachubrey

16-Dec-08 23:20

Hi all.

I have OOP Question. Can i invoke base class methods instead overridens; in C#

Examp:

<br />
<br />
 class BaseClass<br />
 {<br />
      public void Fun1()<br />
      {<br />
        this.Fun2();//I want write here - base class method<br />
<br />
 //What i should write here for invoke Fun2() of this class (exactly this class,<br />
// not  derived), i suppose what i shoul write as in C++ ((BaseClass)this).Fun2(); <br />
//But this not work, in this case still invoke method of derived class.<br />
      }<br />
<br />
      protected virtual void Fun2()<br />
      {<br />
             WriteLine("base class method");<br />
      }<br />
 }<br />
<br />
 class DervClass : BaseClass<br />
 {<br />
      protected overriden void Fun2()<br />
      {<br />
            WriteLine("overriden class method");<br />
      }<br />
<br />
 }<br />
<br />
  ....<br />
DervClass derv = new DervClass();<br />
<br />
derv.Fun1();<br />
<br />

modified on Wednesday, December 17, 2008 6:37 AM

Re: How to invoke base class methods instead overridens

N a v a n e e t h16-Dec-08 23:59

N a v a n e e t h

16-Dec-08 23:59

you can use base.FunctionName(). But the code provided by you is not showing the inheritance.

Navaneeth

How to use google | Ask smart questions

Re: How to invoke base class methods instead overridens

El'Cachubrey17-Dec-08 0:18

El'Cachubrey

17-Dec-08 0:18

N a v a n e e t h wrote:
you can use base.FunctionName(). But the code provided by you is not showing the inheritance.

Thats the point. I want to invoke base method from the base class!!!

Re: How to invoke base class methods instead overridens

N a v a n e e t h17-Dec-08 0:51

N a v a n e e t h

17-Dec-08 0:51

El'Cachubrey wrote:
I want to invoke base method from the base class!!!

Base classes methods are invoked using base keyword from a child class. What are you trying to do?

Navaneeth

How to use google | Ask smart questions

Re: How to invoke base class methods instead overridens

El'Cachubrey17-Dec-08 0:58

El'Cachubrey

17-Dec-08 0:58

Not base classes!!!.
I try to invoke from base class method other method of the same base class even if one overriden in derived class. Like that in C++ ((BaseClass)this).Fun2(); But in C# - it's diffrent i wan't to know how.

Confused | :confused:

Re: How to invoke base class methods instead overridens

#realJSOP17-Dec-08 0:26

#realJSOP

17-Dec-08 0:26

First, you have to do this:

class DervClass : BaseClass

Second, in your derived class, you have to do this:

protected override void Fun2()
{
    base.Fun2();
}

Re: How to invoke base class methods instead overridens

El'Cachubrey17-Dec-08 0:41

El'Cachubrey

17-Dec-08 0:41

John Simmons / outlaw programmer wrote:
First, you have to do this:

class DervClass : BaseClass

Yes, it's just misstyping.

John Simmons / outlaw programmer wrote:
econd, in your derived class, you have to do this:

protected override void Fun2()
{
base.Fun2();
}

I can't do this in derived class snice implemented logic.

Re: How to invoke base class methods instead overridens

#realJSOP17-Dec-08 1:12

#realJSOP

17-Dec-08 1:12

El'Cachubrey wrote:
I can't do this in derived class snice implemented logic.

First you tell us you want to do what I told you how to do, and then you tell us you *can't* do it because of logic in your code. Make up your freakin' mind, or stop wasting our time. If your "logic" prevents you from doing what you need to do, then your code is completely screwed up, and you need to start over.

Re: How to invoke base class methods instead overridens

El'Cachubrey17-Dec-08 1:30

El'Cachubrey

17-Dec-08 1:30

Cool up.

I don't beg you to respond my question. I make example just for explanate what i try to do and i mean exactly what i mean how i can invoke base class member from other base class member even if it's one overriden in derived class. Be more attentive in future .

Re: How to invoke base class methods instead overridens

Simon P Stevens17-Dec-08 1:28

Simon P Stevens

17-Dec-08 1:28

First let me check I understand what you are trying to do

class Program
 {
     static void Main(string[] args)
     {
         MySub instance = new MySub();

         instance.CallMe();

         Console.ReadLine();
     }
 }

 public class MyBase
 {
     public virtual void Method1()
     {
         Console.WriteLine("I want this to run");
     }

     public void CallMe()
     {
         Method1();
     }
 }

 public class MySub : MyBase
 {
     public override void Method1()
     {
         Console.WriteLine("But this is what really gets run");
     }
 }

You create a new instance of the sub class, and call "CallMe" which triggers a method. You want it to trigger the method in the base class, and not the one in the sub class.

Well, like others have said, the standard way to do this would be to put base.Method1() in the Method1 in the subclass to call the base method. But for some reason you don't want to do that. I'm assuming you don't want to do that because sometimes, when you call method1 directly on the subclass, you do want it to run.

This is the nature of what 'override' means. The method1 in the subclass overrides the method1 in the base. Perhaps the override behaviour isn't what you want. Perhaps you should just consider naming the methods with different names. Then you can call which ever one you want to call.

Alternatively, consider using the 'new' keyword.

public class MySub : MyBase
{
    public new void Method1()
    {
        Console.WriteLine("But this is what really gets run");
    }
}

Using the 'new' keyword makes the method1 in the sub class hide the method1 in the base class, but not override it. This means when you cast back down to a base class (or call from within the base class) it's the base's method that gets run, because nothing is overriding it, instead, when you have an instance of the subclass, the method1 just hides the bases method1.

Confusing. Yeah. I can't explain it very clearly.

Try running the snippets I've given you and see the difference.

Be careful if you use new. This isn't very standard behaviour, and other people may easily be surprised by what happens. You should probably just be naming your methods differently if they have different behaviour.

Some links on the subject:
http://rbgupta.blogspot.com/2008/09/method-hiding-polymorphism-in-c.html[^]

http://www.c-sharpcorner.com/UploadFile/jaishmathews/DifferentiateHidingandOverriding02252006123905PM/DifferentiateHidingandOverriding.aspx?ArticleID=ea4ba754-8b02-4bde-8f96-a90b428d3656[^]

Simon

Re: How to invoke base class methods instead overridens

El'Cachubrey17-Dec-08 1:43

El'Cachubrey

17-Dec-08 1:43

Nicely. Instead "Confusing" it's very clear.

Let's make a count:

1. There is no exists way to invoke Base Class method if they overriden in derived classes.

2. Only way to invoke Base Class method it's mark overriden method with "new" keyword in derived class.

Re: How to invoke base class methods instead overridens

Simon P Stevens17-Dec-08 1:50

Simon P Stevens

17-Dec-08 1:50

El'Cachubrey wrote:
1. There is no exists way to invoke Base Class method if they overriden in derived classes.

You can call base.method1() from the derived class. I don't know of any other way. Although I'm not Anders[^], there could be a way, I just can't think of one. Perhaps someone with more experience can confirm or deny this.

El'Cachubrey wrote:
2. Only way to invoke Base Class method it's mark overriden method with "new" keyword in derived class.

Well, like I said, it might not be the only way. It's a way though. Just be aware that the 'new' keyword causes different behaviour to the override keyword. What you are doing is conceptually something slightly different. Make sure you understand all the behaviour differences and consequences and that they are what you want before you do it. (And don't forget, other people who use your code won't be expecting this, so note it heavily in the comments, or consider naming the methods differently)

Simon

Re: How to invoke base class methods instead overridens

El'Cachubrey17-Dec-08 2:10

El'Cachubrey

17-Dec-08 2:10

GRATEFULL

Re: How to invoke base class methods instead overridens

#realJSOP17-Dec-08 2:41

#realJSOP

17-Dec-08 2:41

El'Cachubrey wrote:
1. There is no exists way to invoke Base Class method if they overriden in derived classes.

Wrong, wrong, wrong. I showed you how to do it.

El'Cachubrey wrote:
2. Only way to invoke Base Class method it's mark overriden method with "new" keyword in derived class.
Quote Selected Text

Wrong again. If you make a "new" method, it completely hides the base version from other objects that use your derived class.

Re: How to invoke base class methods instead overridens

PIEBALDconsult17-Dec-08 3:24

PIEBALDconsult

17-Dec-08 3:24

By marking the method in the base class virtual and the method in the derived class override, you are stating that you do not want to be able to call the base class' version directly from an instance of the derived class, and therefore it can't be done.
If, you do want to be able to call the base class' version from an instance of the derived class, then do not use virtual and override.

Re: How to invoke base class methods instead overridens

#realJSOP17-Dec-08 3:44

#realJSOP

17-Dec-08 3:44