Any good tutorials about inhertance and shadowing in vb.net

[muck]

I am learning about inertance & Shadowing in VB.net before interfacing VB.net with AutoCAD.

I am having problems with Shadowing concept. Is there any good tutorials that keeps these

oop concepts simple with simple examples?

Thank you,

[Jeff H]

Here is one example where VB differs.

 

A good book about Visual Basic or google should help

http://msdn.microsoft.com/en-us/library/ms172785.aspx

 

To show a example how they differ

*****EDIT*********

Code will not format correctly it puts it on one line

[color=blue]Public[/color] [color=blue]Class[/color] [color=#2b91af]Shape[/color] 
   [color=blue]Overridable[/color] [color=blue]Sub[/color] Draw     
    MsgBox([color=#a31515]"Base Draw"[/color])     
   [color=blue]End[/color] [color=blue]Sub[/color]     

  [color=blue]Sub[/color] SaveToDatabase   
    MsgBox([color=#a31515]"Base SaveToDatabase"[/color])    
  [color=blue]End[/color] [color=blue]Sub[/color]
[color=blue]End[/color] [color=blue]Class[/color] 

[color=blue]Public[/color] [color=blue]Class[/color] [color=#2b91af]Rectangle[/color]  
 [color=blue]Inherits[/color] [color=#2b91af]Shape[/color] 

   [color=blue]Public[/color] [color=blue]Overrides[/color] [color=blue]Sub[/color] Draw()     
   MsgBox([color=#a31515]"Overrides Draw"[/color])    
  [color=blue]End[/color] [color=blue]Sub[/color]   

[color=blue]Shadows[/color] [color=blue]Sub[/color] SaveToDatabase    
   MsgBox([color=#a31515]"Shawdows SaveToDatebase"[/color])    
[color=blue]End[/color] [color=blue]Sub[/color] 
 [color=blue]End[/color] [color=blue]Class[/color]  

[color=blue]Public[/color] [color=blue]Class[/color] [color=#2b91af]Triangle[/color]    
[color=blue]Inherits[/color] [color=#2b91af]Shape[/color]  

  [color=blue]Public[/color] [color=blue]Overrides[/color] [color=blue]Sub[/color] Draw()       
MsgBox([color=#a31515]"Overrides Draw"[/color]) 
  [color=blue]End[/color] [color=blue]Sub[/color] 
  [color=blue]Shadows[/color] [color=blue]Sub[/color] SaveToDatabase       
MsgBox([color=#a31515]"Shawdows SaveToDatebase"[/color]) 
  [color=blue]End[/color] [color=blue]Sub[/color]
[color=blue]End[/color] [color=blue]Class[/color]

 

Now when you use them in this context you can see the difference

     [color=blue]Dim[/color] rec [color=blue]As[/color] [color=#2b91af]Shape[/color] = [color=blue]New[/color] [color=#2b91af]Rectangle[/color]     
  rec.Draw()     
  rec.SaveToDatabase() 
       [color=blue]Dim[/color] tri [color=blue]As[/color] [color=#2b91af]Triangle[/color] = [color=blue]New[/color] [color=#2b91af]Triangle[/color]     
  tri.Draw()    
   tri.SaveToDatabase()

[muck]

I think understand overwriting but I am having a tough time with vb.net Shadowing.

What does shadowing mean in programming? Is there any good simple examples?

An example that includes a test routine that uses the shadow routine.

Please keep it simple as possable.

thank you,

[Jeff H]

Maybe someone else can explain better but if you understand overrides then I would guess you have a basic understanding of inhertance and polymorphism.

 

Some people might argue that shadows is not a OOP concept and you should not use it.

 

But other than taking the information from these links and posting what they already say,

these links give a good description.

 

http://msdn.microsoft.com/en-us/library/c4swkw24.aspx

http://msdn.microsoft.com/en-us/library/ms172785.aspx

http://msdn.microsoft.com/en-us/library/hya04w5b.aspx

http://msdn.microsoft.com/en-us/library/10kws135.aspx

http://msdn.microsoft.com/en-us/library/b25c8bbc.aspx

[muck]

I guess I need to start form the bottom with a good oop tutorial that gets to the point.

I have been searching the web but it seems like I get lost because there is too much info.

Is there a oop tutorial that that gets to the point and is short and somewhat simple?

I am sure it is going to take some time to absorb oop info.

I want to work on inhertance and polymorphism so I can understand those concepts.

Thank you,