What's in Your Project?

The Properties node represents configuration settings that apply to your entire project and are stored in the .csproj file in your solution folder. These settings include compilation options, security and deployment settings and much more. You make modifications to your project using the Project Designer, which is a set of Property Pages that you access by right-clicking Properties, and selecting Open. For more information, see Modifying Project Properties (Visual C#).

In the context of a project, a reference simply identifies a binary file that your application requires in order to run. Typically, a reference identifies a DLL file such as one of the .NET Framework class library files. It can also reference a .NET assembly (called a shim) that enables your application to call methods on a COM object or native Win32 DLL. If your program creates an instance of a class that is defined in some other assembly, then you must add a reference to that file in your project before you compile your project. To add a reference, click Add Reference on the Project menu. All C# projects by default include a reference to mscorlib.dll, which contains the core .NET Framework classes. You can add references to additional .NET Framework DLLs and other files by clicking the Project menu, and selecting Add Reference.

Note
Do not confuse the concept of a project reference with the concept of reference types in C# or other programming languages. The former refers to a file and its expected location on disk. The latter refers to C# types, which are declared using the class keyword.

A resource is data that is included with your application but can be stored in such a way that it can be modified independently from the other source code. For example, you can store all your strings as resources rather than hard-coding them into the source code. You can then translate the strings into different languages at some later date, and add them to the application folder that you ship to customers without having to recompile your assembly. The five types of resources defined by Visual C# are: strings, images, icons, audio, and files. You add, remove, or edit resources using the Resource Designer, which is accessed on the Resources tab in the Project Designer.

When you create a Windows Forms project, Visual C# adds one form to the project by default and calls it Form1. The two files that represent the form are called Form1.cs and Form1.designer.cs. You write your code in Form1.cs; the designer.cs file is where the Windows Forms Designer writes the code that implements all the actions that you performed by dragging and dropping controls from the Toolbox.

You can add a new form by clicking the Project menu item, and selecting Add Windows Form. Each form has two files associated with it. Form1.cs, or whatever you might name it, contains the source code that you write to configure the form and its controls, such as list boxes and text boxes, and responds to events such as button clicks and keystrokes. In simple Windows Forms projects, you do most or all of your coding in this file.

The Designer.cs file contains the source code that the Forms Designer writes when you drag controls onto the form, set properties in the Properties window, and so on. Typically, you should not edit this file manually at all.

Note
Obviously, if you create a console application project, it will not contain source code files for Windows Forms.

A project may include any number of additional .cs files that may or may not be associated with a particular Windows Form. In the previous illustration of Solution Explorer, program.cs contains the entry point for the application. A single .cs file can contain any number of class and struct definitions. You can add new or existing files or classes to your project by clicking Add New Item or Add Existing Item on the Project menu.