how to prevent none state form from being maximized in c#

Question

i have created a form and set its FormBorderStyle property to none. when i press Windows + UP form will be Maximized. how can i prevent form from maximize? i tried

private void logIn_Resize(object sender, EventArgs e)
        {
            this.WindowState = FormWindowState.Normal;
        }

but its not that i want. with above code when i press Windows + Up form will maximize and then it restores to normal state. but i want to prevent it basically.

Answer 1

Setting the form's MaximizeBox to False should be enough to stop this Aero Snap feature. But Form.CreateParams calculates the wrong style flags for some mysterious reason. I can't single-step it right now due to the 4.7.1 update and don't see the mistake in the source code. It might have something to do with disabling it in the system menu but not the style flags, just a guess.

Anyhoo, hammering the native style flag off by force does solve the problem. Copy-paste this code into your form class:

protected override CreateParams CreateParams {
    get {
        const int WS_MAXIMIZEBOX = 0x00010000;
        var cp = base.CreateParams;
        cp.Style &= ~WS_MAXIMIZEBOX;
        return cp;
    }
}

Answer 2

// Define the border style of the form to a dialog box.
form1.FormBorderStyle = FormBorderStyle.FixedDialog;

// Set the MaximizeBox to false to remove the maximize box.
form1.MaximizeBox = false;

// Set the MinimizeBox to false to remove the minimize box.
form1.MinimizeBox = false;

Credit to How do I disable form resizing for users?