Visual Studio Project Group (IDE)

how to make a group project in visual studio. NET ?

Assume in future that too many words are better than too few and try to provide a full and clear explanation of the problem. What do you mean by "a group project"? Are you talking about a project that multiple people are going to work on? If so then it's just like any other project, as far as VS is concerned.

What a proper development team will do is use some form of source control to each merge their changes into a master copy of the project stored on a server and to get everyone else's changes from that server and merge them into their local copy. That's not going to be so easy for a study group though, because you probably won't have a server that you can all access regularly to use for source control.

Your best bet might be to create a single solution that contains multiple projects and each work on just one project. You can all then merge your projects into the one solution each time you meet. You would have to spend a bit of time up front analysing the project and deciding how to break it up. That part may not be that easy either.

I want in my project there are several projects.

For example:
* Project 1 (windows application)
* Project 2 (Class Library)
* Project 3 (Component)

and I want to merge the three projects mentioned above, in a work area (Group)

This is a perfect example of why you need to provide a proper explanation of what you want to do. I never would have guessed that that's what you meant.

You don't have to do anything special. VS works like that by default. When you create a new project, VS automatically creates a solution and adds the project to it. That's why VS has a Solution Explorer window and not a Project Explorer. If you want to keep multiple related projects to gather then you just add them to the same solution. Just as you can add multiple new or existing items to a project, you can add multiple new or existing projects to a solution.

One advantage of having an application project and its dependent library projects in the same solution is that the library can then reference the projects themselves instead of the output. You can then debug all projects together seamlessly.

The 'group' which you are referring to, is a 'Solution' in visual studio. When you create/open a project, a solution is automatically created by Visual Studio. Select this solution file in the Solution Explorer window and right-click on it. From the context menu you can select Add > New Project to add a new project to the solution, or if the project already is developed, select Add > Existing Project and browse to the existing project that you want to add.

.

Thanks for the explanation, very helpful at all.
Finally today I managed to make it.