Design patterns are considered to be best solution for application design based problems. When we design application or have to implement any task. We have multiple ways to perform that task but we should try to perform that task in best way. There are many tasks/problems, we face frequently whilst development or designing application so there are best solutions for such common problems given by gurus. Design patterns help a lot to minimize frequent and complex problems.
Following are few examples (problems), which could help you in understanding what kind of problems are resolved by design patterns.
- You want to undo work done by user one or multiple times
- Suppose you don’t need to let create multiple objects of same class at a time in any case.
- You don’t know exact class type of which you would need to create object whilst programming/coding.
- You need to change behavior of object without changing of class implementation.
- You might need to have different behavior of same object on change of state of object.
Aforementioned points are just to give you sense of types of problems/tasks, you could have whilst application development and designing.
for complete article on design patterns please click on following link where i have uploaded my article http://www.worldofasp.net/tut/designpattern/Design_Patterns_210.aspx