Good Evening Sir....can you Explain Design pattren of Dotnet

I would love to answer that but am restricted by time and space.

So two simple Google search links - design patterns[^]
design patterns .net[^]

Believe me they contain everything you may like to know.

And please consider doing a search before you ask anything.

Thanks
Ankur

Refer this

http://www.eggheadcafe.com/tutorials/csharp/c6526574-cd2a-40e3-beac-fe3b10a1e694/design-patterns-for-net.aspx[^]

Design pattern is a general reusable solution to a commonly occurring problem

It is not compulsory, but using design pattern will reduce you work and the code will be in a structure manner

Design pattern can be used in any language you write the code

for basics of design pattern check this link
Design pattern

http://www.dofactory.com/Patterns/Patterns.aspx[^]

This is the best website for the design patterns and you can learn a lot with the help of above link

it not necessary to learn patterns but good if you know some companies will ask pattern questions also