Unmanaged Code

[issa82developer]

iam using C# to automate Microsoft Word Document.

when i wanted to create a new World Application i used the following code:

Word._Application oWord;
oWord = new Word.Application();

and i found that Word._Application is an interface and also Word.Application.

The Question IS:

how can i use the methods and properties of the object oWord, i mean its an object of an Interface so i have to implement these methods first.But as i saw
i could use methods of the object oWord without need to write any Implementation???
i dont understand the mechanism of that kind of structurs....????