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title Tutorial: Debug C# code and inspect data
description Learn features of the Visual Studio debugger and how to start the debugger, step through code, and inspect data in a C# application.
ms.date 02/11/2026
ms.subservice debug-diagnostics
ms.topic tutorial
dev_langs
CSharp
helpviewer_keywords
debugger
author mikejo5000
ms.author mikejo
ms.update-cycle 90-days

Tutorial: Learn to debug C# code using Visual Studio

This article introduces the features of the Visual Studio debugger in a step-by-step walkthrough. When you debug your app, it usually means that you're running your application with the debugger attached. When you do this task, the debugger provides many ways to see what your code is doing while it runs. You can step through your code and look at the values stored in variables. You can set watches on variables to see when values change. You can examine the execution path of your code to see whether a branch of code is running.

If this article is the first time that you try to debug code, see Debug for absolute beginners. If you want a higher-level view of the debugger features, see Overview of the Visual Studio debugger.

Although the demo app is C#, most of the features are applicable to C++, Visual Basic, F#, Python, JavaScript, and other languages supported by Visual Studio. F# doesn't support Edit-and-continue. F# and JavaScript don't support the Autos window. The screenshots are in C#.

In this tutorial, you will:

[!div class="checklist"]

  • Start the debugger and hit breakpoints
  • Learn commands to step through code in the debugger
  • Inspect variables in data tips and debugger windows
  • Examine the call stack

Prerequisites

You must have Visual Studio installed and the .NET desktop development workload.

If you need to install Visual Studio, get it for free at Visual Studio downloads.

If you already have Visual Studio but the .NET desktop development workload isn't installed, go to Tools > Get Tools and Features.... In the Visual Studio Installer, choose the .NET desktop development workload, then choose Modify.

Create a project

First, create a C#/.NET console app project. The project template includes all the files you need before you add anything.

::: moniker range=">=visualstudio"

  1. Open Visual Studio. If the start window isn't open, select File > Start Window.

  2. On the start window, select Create a new project.

  3. On the Create a new project window, enter console in the search box. Next, choose C# from the Language list, and then choose Windows from the Platform list.

    After you apply the language and platform filters, choose the Console App template, and then select Next.

    :::image type="content" source="media/visualstudio/csharp-get-started-create-console-project.png" alt-text="Screenshot of the 'Console Application' template in the 'Create a new project' window of Visual Studio.":::

    [!NOTE] If you don't see the Console App template, you can install it from the Create a new project window. In the Not finding what you're looking for? message, choose the Install more tools and features link. Then, in the Visual Studio Installer, choose the .NET desktop development workload.

  4. In the Configure your new project window, enter GetStartedDebugging in the Project name box. Then, select Next.

  5. In the Additional information window, ensure .NET 10.0 is selected in the Framework dropdown menu, and then select Create.

::: moniker-end

::: moniker range="=vs-2022"

  1. Open Visual Studio. If the start window isn't open, select File > Start Window.

  2. On the start window, select Create a new project.

  3. On the Create a new project window, enter console in the search box. Next, choose C# from the Language list, and then choose Windows from the Platform list.

    After you apply the language and platform filters, choose the Console App template, and then select Next.

    :::image type="content" source="media/vs-2022/get-started-create-console-project.png" alt-text="Screenshot of the 'Console Application' template in the 'Create a new project' window of Visual Studio 2022.":::

    [!NOTE] If you don't see the Console App template, you can install it from the Create a new project window. In the Not finding what you're looking for? message, choose the Install more tools and features link. Then, in the Visual Studio Installer, choose the .NET desktop development workload.

  4. In the Configure your new project window, enter GetStartedDebugging in the Project name box. Then, select Next.

  5. In the Additional information window, ensure .NET 8.0 is selected in the Framework dropdown menu, and then select Create.

::: moniker-end

Visual Studio opens your new project.

Create the application

In Program.cs, replace all of the default code with the following code:

using System;

class ArrayExample
{
   static void Main()
   {
      char[] letters = { 'f', 'r', 'e', 'd', ' ', 's', 'm', 'i', 't', 'h'};
      string name = "";
      int[] a = new int[10];
      for (int i = 0; i < letters.Length; i++)
      {
         name += letters[i];
         a[i] = i + 1;
         SendMessage(name, a[i]);
      }
      Console.ReadKey();
   }

   static void SendMessage(string name, int msg)
   {
      Console.WriteLine("Hello, " + name + "! Count to " + msg);
   }
}

Start the debugger!

::: moniker range=">=vs-2022"

Mostly, this article uses keyboard shortcuts. It's a fast way to execute debugger commands. Equivalent commands, such as toolbar or menu commands, are also available.

  1. To start the debugger, select F5, or choose the Debug Target button in the Standard toolbar, or choose the Start Debugging button in the Debug toolbar, or choose Debug > Start Debugging from the menu bar.

    :::image type="content" source="media/vs-2022/dbg-tour-start-debugging.png" alt-text="Screenshot of the Debug Target button in the Standard toolbar of Visual Studio 2022.":::

    F5 starts the app with the debugger attached to the app process. Since you started debugging, the app runs to completion and you see the console output.

    Hello, f! Count to 1
Hello, fr! Count to 2
Hello, fre! Count to 3
Hello, fred! Count to 4
Hello, fred ! Count to 5
Hello, fred s! Count to 6
Hello, fred sm! Count to 7
Hello, fred smi! Count to 8
Hello, fred smit! Count to 9
Hello, fred smith! Count to 10

  2. To stop the debugger, select Shift+F5, or choose the Stop Debugging button in the Debug toolbar, or choose Debug > Stop Debugging from the menu bar.

    :::image type="content" source="media/vs-2022/dbg-tour-stop-debugging.png" alt-text="Screenshot of the Stop debugging button in the Debug toolbar of Visual Studio 2022.":::

  3. In the console window, select any key to close the console window.

::: moniker-end

Set a breakpoint and start the debugger

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  1. In the for loop of the Main function, set a breakpoint by clicking in the left margin on the following line of code:

    name += letters[i];

    A red circle appears where you set the breakpoint.

    :::image type="content" source="media/vs-2022/dbg-tour-breakpoint.png" alt-text="Screenshot of a breakpoint in Visual Studio 2022.":::

    Breakpoints are an essential feature of reliable debugging. You can set breakpoints where you want Visual Studio to pause your running code. You can look at the values of variables or the behavior of memory or find out whether a branch of code runs.

  2. To start debugging, select F5, or choose the Debug Target button in the Standard toolbar, or choose the Start Debugging button in the Debug toolbar, or choose Debug > Start Debugging from the menu bar. The app starts and the debugger runs to the line of code where you set the breakpoint.

    :::image type="content" source="media/vs-2022/get-started-set-breakpoint.png" alt-text="Screenshot showing a breakpoint in the code editor of Visual Studio 2022, with code execution paused at the breakpoint.":::

    The yellow arrow points to the statement on which the debugger paused. App execution pauses at the same point, with the statement not yet executed.

    When the app isn't running, F5 starts the debugger, which runs the app until it reaches the first breakpoint. If the app is paused at a breakpoint, then F5 continues running the app until it reaches the next breakpoint.

    Breakpoints are a useful feature when you know the line or section of code that you want to examine in detail. For more about the different types of breakpoints you can set, such as conditional breakpoints, see Use the right type of breakpoint.

::: moniker-end

Navigate code and inspect data by using data tips

::: moniker range=">=vs-2022"

  1. While code execution is paused on the name += letters[i] statement, hover over the letters variable to see a data tip showing the array size and element type, char[10].

    [!NOTE] One of the most useful features of the debugger is its ability to inspect a variable. Often, when you're trying to debug an issue, you're attempting to find out whether variables have values that you expect at a particular time. Viewing data tips is a good way to check that.

  2. Expand the letters variable to view all its array elements and their values.

    :::image type="content" source="media/vs-2022/get-started-view-data-tip.png" alt-text="Screenshot of a debugger data tip in Visual Studio 2022 that shows the element values for the 'letters' array variable.":::

  3. Hover over the name variable to see its current value, which is an empty string.

  4. To advance the debugger to the next statement, select F10, or choose the Step Over button in the Debug toolbar, or choose Debug > Step Over from the menu bar. Select F10 twice more to move past the SendMessage method call.

    F10 advances the debugger without stepping into function or methods, although their code still executes. In this way, you skipped debugging the code in the SendMessage method, which isn't relevant right now.

  5. To iterate through the for loop a few times, select F10 repeatedly. During each loop iteration, pause at the breakpoint, and then hover over the name variable to check its value in the data tip.

    :::image type="content" source="media/vs-2022/get-started-data-tip.png" alt-text="Screenshot of a debugger data tip in Visual Studio 2022 that shows the string value for the 'name' variable.":::

    The value of the variable changes with each iteration of the for loop, showing values of f, then fr, then fre, and so on. To advance the debugger through the loop faster, select F5 instead, which advances to your breakpoint instead of the next statement.

  6. While code execution is paused in the for loop of the Main method, select F11, or choose the Step Into button from the Debug toolbar, or choose Debug > Step Into from the menu bar, until you reach the SendMessage method call.

    The debugger should be paused at this line of code:

    SendMessage(name, a[i]);

  7. To step into the SendMessage method, select F11 again.

    The yellow pointer advances into the SendMessage method.

    :::image type="content" source="media/vs-2022/get-started-f11.png" alt-text="Screenshot showing the execution pointer of the debugger within the 'SendMessage' method.":::

    F11 helps you examine the execution flow of your code in more depth. To step into a method from a method call, select F11. By default, the debugger skips stepping into nonuser methods. To learn about debugging nonuser code, see Just My Code.

    After you finish debugging the SendMessage method, you're ready to return to the for loop of the main method.

  8. To leave the SendMessage method, select Shift+F11, or choose the Step Out button in the Debug toolbar, or choose Debug > Step Out from the menu bar.

    Step Out resumes app execution and advances the debugger until the current method or function returns.

    You see the yellow pointer back in the for loop of the Main method, paused at the SendMessage method call. For more information on different ways to move through your code, see Navigate code in the debugger.

::: moniker-end

Navigate code using Run to Click

::: moniker range=">=vs-2022"

  1. Select F5 to advance to the breakpoint again.

  2. In the code editor, hover over the Console.WriteLine method call in the SendMessage method until the Run to Click button appears. The tooltip for the button shows "Run execution to here."

    :::image type="content" source="media/vs-2022/get-started-run-to-click.png" alt-text="Screenshot showing the Run to Click button in Visual Studio 2022.":::

  3. Choose the Run to Click button. Alternatively, with your cursor at the Console.WriteLine statement, select Ctrl+F10. Or, right-click the Console.WriteLine method call, and choose Run to Cursor from the context menu.

    The debugger advances to the Console.WriteLine method call.

    Using the Run to Click button is similar to setting a temporary breakpoint. This approach is handy for getting around quickly within a visible region of your app code in an open file.

::: moniker-end

Restart your app quickly

::: moniker range=">=vs-2022"

To rerun your app from the beginning in the debugger, select Ctrl+Shift+F5, or choose the Restart button in the Debug toolbar, or choose Debug > Restart from the menu bar.

:::image type="content" source="media/vs-2022/dbg-tour-restart-debugging.png" alt-text="Screenshot of the Restart button in the Debug toolbar of Visual Studio 2022.":::

Restart stops the debugger and then restarts it, in one step. When the debugger restarts, it runs to the first breakpoint, which is the breakpoint you previously set inside the for loop, and then pause.

::: moniker-end

Inspect variables with the Autos and Locals windows

::: moniker range=">=vs-2022"

The Autos and Locals windows show variable values while you're debugging. The windows are only available during a debug session. The Autos window shows variables used on the current line that the debugger is at and the preceding line. The Locals window shows variables defined in the local scope, which is usually the current function or method.

  1. While the debugger is paused, view the Autos window at the bottom of the code editor.

    If the Autos window is closed, select Ctrl+D, A, or choose Debug > Windows > Autos from the menu bar.

  2. With the debugger still paused, view the Locals window, in a tab next to the Autos window.

    If the Locals window is closed, select Ctrl+D, L, or choose Debug > Windows > Locals.

  3. In the Locals window, expand the letters variable to see its array elements and their values.

    :::image type="content" source="media/vs-2022/get-started-locals-window.png" alt-text="Screenshot of the Locals window in Visual Studio 2022, with the 'letters' array variable expanded.":::

For more about the Autos and Locals windows, see Inspect variables and return values.

::: moniker-end

Set a watch

::: moniker range=">=vs-2022"

You can specify a variable, or an expression, that you want to keep an eye on as you step through code by adding it to the Watch window.

  1. While the debugger is paused, right-click the name variable and choose Add Watch.

    The Watch window opens, by default, at the bottom of the code editor.

  2. After you set the watch on the name variable, step through your code to see the value of the name variable change with each for loop iteration.

    Unlike the other variable windows, the Watch window always shows the variables that you're watching. Variables that are out of scope are displayed as unavailable.

For more information about the Watch window, see Watch variables with Watch windows.

::: moniker-end

Examine the call stack

::: moniker range=">=vs-2022"

The Call Stack can help you understand the execution flow of your app. It shows the order in which methods and functions are getting called.

  1. While the debugger is paused in the for loop, view the Call Stack window, which opens by default in the lower right pane of the code editor.

    If the Call Stack window is closed, select Ctrl+D, C, or choose Debug > Windows > Call Stack from the menu bar.

    In the Call Stack window, you see the yellow pointer at the current Main method.

  2. Select F11 a few times until you see the debugger pause in the SendMessage method.

    The top line of the Call Stack window shows the current function, which is the SendMessage method. The second line shows that the SendMessage method was called from the Main method.

    :::image type="content" source="media/vs-2022/get-started-call-stack.png" alt-text="Screenshot of the Call Stack window in Visual Studio 2022.":::

    [!NOTE] The Call Stack window is similar to the Debug perspective in some IDEs, like Eclipse.

    In the Call Stack window, you can double-click a line of code to go to that source code, which changes the current scope under inspection by the debugger. This action doesn't advance the debugger.

    You can also use right-click menus from the Call Stack window to do other things. For example, you can insert breakpoints into specified functions, advance the debugger by using Run to Cursor, or go to source code.

For more about the Call Stack, see View the call stack.

::: moniker-end

Next step

In this tutorial, you learned how to start the debugger, step through code, and inspect variables. You might want to get a high-level look at debugger features along with links to more information.

[!div class="nextstepaction"] Overview of the Visual Studio debugger