# Visual Studio

Find your way around Visual Studio 2026, from solutions and projects to running a program and stepping through it with the debugger.

Novice · Software Development · C# · Updated November 3, 2026

## After this lesson you can

- Explain how a solution, its projects and their files fit together in Visual Studio
- Pause a running program at a breakpoint and step through it with the debugger

## Key takeaways

- A project is one program or library, with its settings in a `.csproj` file. A solution (`.slnx`) holds the projects that belong together.
- Each exercise in this course is a solution with two projects: your program, and the tests that check your answers.
- Ctrl+F5 builds and runs the startup project, and F5 runs it with the debugger. If the build fails, the Error List shows what's wrong and where.
- A breakpoint pauses your program on a line, so you can see every variable's value, and F10 then runs one line at a time.
- When a program gives a wrong answer, put a breakpoint where things should be right and step forward until a value isn't what you expect.

**Visual Studio** is the IDE you'll use for C# in this course. It's a large program with hundreds of menus, but you only need a few parts of it to start: where your files live, how to run your program, and how to watch it run, one line at a time.

![Visual Studio 2026 with Solution Explorer on the right, the code editor in the middle and the Output window below](https://www.ask-codey.com/lessons/TODO)

## Solutions and projects

Visual Studio organizes your work in two layers:

- A **project** is one program or library: its code files, its settings and the libraries it uses. Its settings live in a **project file** that ends in `.csproj`.
- A **solution** is a container for one or more projects that belong together, such as a web app and the tests that check it. Its file ends in `.slnx` (older solutions use `.sln`).

When you open a solution, Visual Studio opens every project in it. In this course, each exercise is a solution with two projects: your program, and the tests that check your answers.

```text
VariablesExercise.slnx            the solution
├── VariablesExercise/            a project: your program
│   ├── VariablesExercise.csproj
│   └── Program.cs
└── VariablesExercise.Tests/      a project: the tests
    ├── VariablesExercise.Tests.csproj
    └── AnswerTests.cs
```

## Solution Explorer

**Solution Explorer**, usually on the right, shows your solution, its projects and their files as a tree. Double-click a file to open it in the editor. Right-click a project to add a file to it, or to choose **Set as Startup Project**: the project that runs when you press the Run button.

If Solution Explorer has disappeared, open it again from **View > Solution Explorer** (or press **Ctrl+Alt+L**).

## Running your program

| To | Press | Menu |
|---|---|---|
| Run without the debugger | **Ctrl+F5** | Debug > Start Without Debugging |
| Run with the debugger | **F5** | Debug > Start Debugging |
| Stop a running program | **Shift+F5** | Debug > Stop Debugging |

Both kinds of run first **build** your program: Visual Studio compiles every project the startup project needs. If your code has a mistake the compiler can find, the build fails and the **Error List** window (**View > Error List**) shows what's wrong and on which line. Double-click an error to jump to it.

## The debugger

A program runs thousands of lines a second, far too fast to watch. The **debugger** lets you pause it, look at every variable, and move forward one line at a time.

Try it now. You need a project to run, so make a quick one:

1. In Visual Studio, choose **File > New > Project** (or **Create a new project** in the start window).
2. Choose **Console App** (the one marked **C#**), then **Next**.
3. Set **Project name** to `DebuggerTry`, click **Next**, then **Create**.
4. In Solution Explorer, double-click `Program.cs` and replace its code with this program.

Don't worry about how the code works yet. `int[]` holds a list of scores, and `foreach` visits each score in turn. You will learn both in the Arrays and Loops chapter.

```csharp
int[] scores = { 21, 14, 35, 28 };
int total = 0;

foreach (int score in scores)
{
    total = total + score;
}

Console.WriteLine("Total points: " + total);
```

```text
Total points: 98
```

1. Click in the gray margin to the left of the line `total = total + score;`. A red dot appears: a **breakpoint**, a place where the program will pause.
2. Press **F5**. The program starts, and stops on that line before running it. A yellow arrow shows where it is.
3. Hover over `total` and `score` to see their values. The **Locals** window at the bottom shows every variable at once.
4. Press **F10** (**Step Over**) to run one line. Press **F5** (**Continue**) to run until the breakpoint is reached again. Watch `total` grow: 21, 35, 70, 98.
5. Click the red dot to remove the breakpoint, then press **F5** to let the program finish.

| Key | Name | What it does |
|---|---|---|
| **F9** | Toggle Breakpoint | Adds or removes a breakpoint on the current line |
| **F10** | Step Over | Runs the current line, then pauses on the next one |
| **F11** | Step Into | Like Step Over, but goes inside a method the line calls |
| **F5** | Continue | Runs until the next breakpoint, or to the end |

When a program gives a wrong answer, the debugger is how you find out why: put a breakpoint where things should be right, and step forward until a value isn't what you expect.

## Check yourself

2 questions to try on the lesson page.

## So what

Visual Studio does three jobs for you: it keeps your projects organized in a solution, it builds and runs them with one key, and its debugger shows you what your program is really doing, line by line.

## Key terms

- [Visual Studio](https://www.ask-codey.com/glossary/visual-studio)
- [Solution](https://www.ask-codey.com/glossary/solution)
- [Build](https://www.ask-codey.com/glossary/build)
- [Debugger](https://www.ask-codey.com/glossary/debugger-c-sharp)
- [Breakpoint](https://www.ask-codey.com/glossary/breakpoint-c-sharp)

## Cheat sheets

- [Visual Studio](https://www.ask-codey.com/cheat-sheets/development-tools-visual-studio-cheat-sheet)

Source: https://www.ask-codey.com/lessons/development-tools-visual-studio