Debugging Preparation: Windows Forms Applications
Applies to: 
Visual Studio 
Visual Studio for Mac
Note
This article applies to Visual Studio 2017. If you're looking for the latest Visual Studio documentation, see Visual Studio documentation. We recommend upgrading to the latest version of Visual Studio. Download it here
The Windows Forms App project template creates a Windows Forms application. Debugging this type of application in Visual Studio is straightforward. For information on creating a project of this type, see Create a Windows Form App.
When you create a Windows Forms project with the project template, Visual Studio automatically creates required settings for the Debug and Release configurations. If necessary, you can change these settings. These settings can be changed in the <project name> Property Pages dialog box (My Project in Visual Basic).
For more information, see Recommended Property Settings.
The following table displays one additional recommended property setting.
Configuration Properties in Debug tab
| Property Name | Setting |
|---|---|
| Start Action | - Set to Start project, most of the time. Set to Start external program if you want to start another executable when you start debugging (usually for debugging DLLs). |
You can debug Windows Forms applications from inside Visual Studio, or by attaching to an already running application. For more information about attaching, see Attach to Running Processes.
To debug a C#, F#, or Visual Basic Windows Forms application
Open the project in Visual Studio.
Create breakpoints as needed.
Because Windows Forms applications are event-driven, your breakpoints will go into event handler code, or into methods called by event handler code. Typical events in which to place breakpoints include:
Events associated with a control, such as Click, Enter, etc.
Events associated with application startup and shutdown, such as Load, Activated, etc.
Focus and Validation Events.
For more information, see Creating Event Handlers in Windows Forms.
On the Debug menu, click Start.
Debug using the techniques discussed in First look at the debugger.