How do I make a WinForms app go Full Screen

Question

I have a WinForms app that I am trying to make full screen (somewhat like what VS does in full screen mode).

Currently I am setting FormBorderStyle to <

Answer 1

I worked on Zingd idea and made it simpler to use.

I also added the standard F11 key to toggle fullscreen mode.

Setup

Everything is now in the FullScreen class, so you don't have to declare a bunch of variables in your Form. You just instanciate a FullScreen object in your form's constructor :

FullScreen fullScreen;

public Form1()
{
    InitializeComponent();
    fullScreen = new FullScreen(this);
}

Please note this assumes the form is not maximized when you create the FullScreen object.

Usage

You just use one of the classe's functions to toggle the fullscreen mode :

fullScreen.Toggle();

or if you need to handle it explicitly :

fullScreen.Enter();
fullScreen.Leave();

Code

using System.Windows.Forms;


class FullScreen
{ 
    Form TargetForm;

    FormWindowState PreviousWindowState;

    public FullScreen(Form targetForm)
    {
        TargetForm = targetForm;
        TargetForm.KeyPreview = true;
        TargetForm.KeyDown += TargetForm_KeyDown;
    }

    private void TargetForm_KeyDown(object sender, KeyEventArgs e)
    {
        if (e.KeyData == Keys.F11)
        {
            Toggle();
        }
    }

    public void Toggle()
    {
        if (TargetForm.WindowState == FormWindowState.Maximized)
        {
            Leave();
        }
        else
        {
            Enter();
        }
    }
        
    public void Enter()
    {
        if (TargetForm.WindowState != FormWindowState.Maximized)
        {
            PreviousWindowState = TargetForm.WindowState;
            TargetForm.WindowState = FormWindowState.Normal;
            TargetForm.FormBorderStyle = FormBorderStyle.None;
            TargetForm.WindowState = FormWindowState.Maximized;
        }
    }
      
    public void Leave()
    {
        TargetForm.FormBorderStyle = FormBorderStyle.Sizable;
        TargetForm.WindowState = PreviousWindowState;
    }
}