|
Thnx Stefan.
Regards,
Panicker.
|
|
|
|
|
An interface defines a contract. It contains only signatures of methods, properties, etc.
An abstract class can contain implementations, but cannot be instantiated.
A good way to determine if you need an abstract class vs. interface would be:
If you plan on having derived objects, all of which will need to do some of the same thing, you should use an abstract class.
Keep in mind, that abstract classes and interfaces can be used in conjunction where appropriate.
|
|
|
|
|
Can we say that Interface is pure virtual form of an abstract class? (similar to OOPS concept)
-rt
|
|
|
|
|
ArtiGujare wrote: Can we say that Interface is pure virtual form of an abstract class? (similar to OOPS concept)
Yes, you could, but I don't know if that would make it less or more confusing...
An interface contains no implementation, in much the same way that a pure virtual method doesn't contain any implementation.
However, an important difference is that you inherit a class, but you implement an interface. As .NET doesn't have multiple inheritance, a class can only inherit from one base class, but you can make a class implement as many interfaces as you like.
---
single minded; short sighted; long gone;
|
|
|
|
|
Another example you often see is an abstract class partially implementing an interface. A good example of this is System.Collections.DictionaryBase providing partial implementation of common functionality to System.Collections.IDictionary interface.
-----
Formerly MP(2)
If atheism is a religion, then not collecting stamps is a hobby. -- Unknown
|
|
|
|
|
Thnx Centriste nd Guffa.
Regards,
Panicker.
|
|
|
|
|
Paul,thnx fr the clarification.
Regards,
Panicker.
|
|
|
|
|
Hi..Let me make it clear to you that interface is not a substitue for abstract class..Abstract class simply act as a base for all the classes that are derived from it(for ex lets say class stundent,class teacher is derived from some class "xyz" which contains feild called organization name,which is reqd by both the derived classes).Since this base class alone itself is of no use so by adding keyword abstract it is restricted from getting Instansiate.
Now coming to Interface...since c# does not support multiple inheritance so we can use interface where we will mention method signature only..and the class implementing interface should define that method..now u might be thinking that how interface will be a solution for non supporting multiple inheritance nature of c#..well in a class you can implement multiple interfaces..
Well abstract class and interface are often seen together..reason is that we need not to implement interface for each class separetly..so implement interface for abstract class which acts as a base class and all the classes that derived from this abstract class can make use of interface implemented once for abstract class..
|
|
|
|
|
Rahul thnx fr ur detailed explanation.
Regards,
Panicker.
|
|
|
|
|
Difference between Abstract classes and Interface
Little background:
A real world entity is represented in an OOP world as object. Objects are defined as classes any language.
A class defines objects in two aspects
Object's characteristics - Data Members
Object's functionality - Member functions
So, when the classes that are forced to provide implementations of the functions prototypes that are defined in either ‘interfaces’ or a ‘abstract class’ are not belonging to the same family (having some inherited parental characteristics from same parent directly or indirectly) but are rather related through some functionalities then 100% we will go with interface and if above said classes are belonging to same family then we should go with abstract class inheritance.
Also in case of inheritance as everything is a specialization of base parent object so there is allowance of providing some default definitions of the functions that are needed to be implemented further by specialized classes. This is not any way allowed in interfaces because implementing classes are not belonging to same family and are not any way related by characteristics.
An Example:
We have four real world objects:
• Airplane
• Bird
• Sparrow
• Eagle
We have one method that is a functionality of all above objects
• Fly
Now all objects share common functionality flying in air but differ in the mechanism they use to fly.
Also by close look we see that in general there is some common characteristics (as well as some common functionalities) between Sparrow and Eagle that can be a part of common class Bird (that has to be abstract because there is no real thing like bird!). But any way Airplane can't be related to Bird or its specialized classes Sparrow and Eagle.
So if want to expose fly functionality to outer world and want their implementations in Airplane and Sparrow (or any bird), so I will 100% go for Interface and Abstract classes will be a big NO!
But if we exclude Airplane want that fly functionality is exposed to outer world and its implementing classes are Bird, Sparrow and Eagle then 'Abstract Classes' is the best of best choice.
Happy programming! Please feel free in writing to me for further clarifications on other OOP concepts (im.himanshu2006@gmail.com)
Himanshu
|
|
|
|
|
Difference between Abstract classes and Interface
Little background:
A real world entity is represented in an OOP world as object. Objects are defined as classes any language.
A class defines objects in two aspects
Object's characteristics - Data Members
Object's functionality - Member functions
So, when the classes that are forced to provide implementations of the functions prototypes that are defined in either ‘interfaces’ or a ‘abstract class’ are not belonging to the same family (having some inherited parental characteristics from same parent directly or indirectly) but are rather related through some functionalities then 100% we will go with interface and if above said classes are belonging to same family then we should go with abstract class inheritance.
Also in case of inheritance as everything is a specialization of base parent object so there is allowance of providing some default definitions of the functions that are needed to be implemented further by specialized classes. This is not any way allowed in interfaces because implementing classes are not belonging to same family and are not any way related by characteristics.
An Example:
We have four real world objects:
• Airplane
• Bird
• Sparrow
• Eagle
We have one method that is a functionality of all above objects
• Fly
Now all objects share common functionality flying in air but differ in the mechanism they use to fly.
Also by close look we see that in general there is some common characteristics (as well as some common functionalities) between Sparrow and Eagle that can be a part of common class Bird (that has to be abstract because there is no real thing like bird!). But any way Airplane can't be related to Bird or its specialized classes Sparrow and Eagle.
So if want to expose fly functionality to outer world and want their implementations in Airplane and Sparrow (or any bird), so I will 100% go for Interface and Abstract classes will be a big NO!
But if we exclude Airplane want that fly functionality is exposed to outer world and its implementing classes are Bird, Sparrow and Eagle then 'Abstract Classes' is the best of best choice.
Happy programming! Please feel free in writing to me for further clarifications on other OOP concepts (im.himanshu2006@gmail.com)
Himanshu
|
|
|
|
|
i am trying to create an excel like interface where headers must remain still verticaly and the detail section can be scrolled. but when user will scroll detail section horizontly, header section must also scroll accordingly. i have put bot in different rows of tableLayoutPanel and a panel control is containing headers and another panel is containing detail section.
i have also wrote some code in OnScroll event procedure but still unable to achieve my goal.
need help!
*************************
SetNewGoal:
while (GoalNotAchieved){}
goto SetNewGoal;
*************************
|
|
|
|
|
why don't you try modiffying DataGridView?!.. (or DataGrid in framework 1.1)..
life is study!!!
|
|
|
|
|
what i am trying to create is not exactly an excel sheet. basically it is an admin section of Media Schedular Application which shows schedules defined in schedule controls in detail section and the header contains a ruler bar to show the scale in minutes. this schedular shows records for one month and of all four quarters of screen.
i have two panel controls named pnlHeader (no scroll bars) and pnlDetail (both vertical and horizontal scroll bars). when a user scrolls vertically up and down on pnlDetail, there is no effect on pnlHeader but when user will scroll horizontly on pnlDetail the other panel named pnlHeader will also scroll accordingly.
*************************
SetNewGoal:
while (GoalNotAchieved){}
goto SetNewGoal;
*************************
|
|
|
|
|
Hi, I have 2 forms, on one form i want to browse image and want to save them in array or arraylist and show on 2nd form that selected image. How would that be done?
One more query is that if i want to show that image in 2nd form can i set the size of image to be shown in a proper place as thier will be some more images will be later on adding to that form as well.
Please help. Thanks
|
|
|
|
|
private void browseBtn_Click(object sender, EventArgs e)<br />
{<br />
openFile.InitialDirectory = @"C:\";<br />
openFile.Filter = "JPEG files (*.jpg)|*.jpg|GIF files (*.gif)|*.gif | BMP files (*.bmp)|*.bmp";<br />
openFile.FilterIndex = 2;<br />
openFile.RestoreDirectory = true;<br />
if (openFile.ShowDialog() != DialogResult.Cancel)<br />
{<br />
imgTextbox.Text = openFile.FileName;<br />
<br />
}<br />
else<br />
{<br />
imgTextbox.Text = "";<br />
}<br />
<br />
<br />
private void LoadGameButton_Click(object sender, EventArgs e)<br />
{<br />
TicTacToe tic=new TicTacToe(usernametextBox.Text);<br />
tic.Show();<br />
this.Hide();<br />
}
To be more specific the browse action on first form now when i select image in the textbox and click on loadgamebutton that selected image should appear on next form.
I added Picturebox tool on 2nd form as well but dont know know how to implement the above functionality.
Thanks
|
|
|
|
|
Thanks it worked but one more thing is how to give size to that image as it has been passed as a parameter. I want to give specific size to image when its loaded?
Here is my code
<br />
Login.cs<br />
<br />
private void LoadGameButton_Click(object sender, EventArgs e)<br />
{<br />
TicTacToe tic=new TicTacToe(usernametextBox.Text,imgTextbox.Text);<br />
tic.Show();<br />
this.Hide();<br />
}
TicTacToe.cs<br />
<br />
public TicTacToe(string strText,string img)<br />
{<br />
InitializeComponent();<br />
if (strText.Equals(""))<br />
{<br />
label2.Text = "Guest";<br />
}<br />
else<br />
{<br />
label2.Text = strText;<br />
pictureBox1.Load(img);<br />
}<br />
}
|
|
|
|
|
It worked now the image is in proper shape in the picture box but now the next question is
"how u will put them in some arraylist so i can show multiple images at one time in the picturebox on the form".
Thanks
|
|
|
|
|
Any help please.. 
|
|
|
|
|
PERFECT PERFECT IT WORKED THANKS A MILLION..THANKS THANKS
|
|
|
|
|
Please help
i have a customer id in textbox, a listview listing 2 to 3 items. So what i want is to insert this into a database with out the id on the textbox changing. Which means i want to add 3 rows at the same time, without changing the id in the textbox.
ID on TextBox = 1
Sample on ListView
Name Descr Amount
Mouse Black 20
Keyboard Black 30
USB 256MB 200
This is what i want the output to be like
sample on Database
1 Mouse Black 20
1 Keyboard Black 30
1 USB 256MB 200
Please
Back of i'm coding!!!!
|
|
|
|
|
Suppose:
Text Box = tb
List Box = lb
Pseudo code :
for(int i=0; i<lb.items.count;i++)
{
insert into table (custid, itemid)
values( tb.text, lb.items[i].text)
}
-- modified at 7:37 Wednesday 16th May, 2007
*************************
SetNewGoal:
while (GoalNotAchieved){}
goto SetNewGoal;
*************************
|
|
|
|
|
Thanks
I understand this using a listbox, but i'm using a ListView with 3 column and 2 rows.
So what i want is get Cell1, cell2, and cell3 at the same time and insert them
Aints never sleep at all, so why should I?
|
|
|
|
|
hi
make dataset of ur data...
and update like this
dataadapter.update(dataset);
i.e.
da.update(ds);
|
|
|
|
|
General 
News 
Suggestion 
Question 
Bug 
Answer 
Joke 
Praise 
Rant 
Admin 
Submit an article or tip
