Unity: NativeWinAlert (Windows MessageBox / Alert Dialog for Unity games)

NativeWinAlert.cs

using System;
using System.Runtime.InteropServices;

/// <see>https://docs.microsoft.com/en-us/windows/desktop/api/winuser/nf-winuser-messagebox</see>
public static class NativeWinAlert
{
    [System.Runtime.InteropServices.DllImport("user32.dll")]
    private static extern System.IntPtr GetActiveWindow();

    public static System.IntPtr GetWindowHandle()
    {
        return GetActiveWindow();
    }

    [DllImport("user32.dll", SetLastError = true)]
    static extern int MessageBox(IntPtr hwnd, String lpText, String lpCaption, uint uType);

    /// <summary>
    /// Shows Error alert box with OK button.
    /// </summary>
    /// <param name="text">Main alert text / content.</param>
    /// <param name="caption">Message box title.</param>
    public static void Error(string text, string caption)
    {
        try
        {
            MessageBox(GetWindowHandle(), text, caption, (uint)(0x00000000L | 0x00000010L));
        }
        catch (Exception ex) { }
    }
}

This is the equivalent of using a MessageBox in a .NET Windows Forms application, except falling back to the native counterpart.

Example use:

NativeWinAlert.Error("Something went wrong.", "Message title");

Notes:

• Alert dialogs are synchronous and blocking. I only use them for critical startup errors (e.g. Steamworks not initializing properly) to inform the user before quitting the app.
• This is (obviously) not cross platform at all, as it invokes native Windows APIs.
• It shouldn't break if there is different foreground window (not unity) as GetActiveWindow "[retrieves] the window handle to the active window attached to the calling thread's message queue".

To see all style / button options for the Messagebox:
https://docs.microsoft.com/en-us/windows/desktop/api/winuser/nf-winuser-messagebox

Works great :) This was quite weird to work with especially that System.Windows.Forms.dll wouldn't even import, thank you.

Thank you so much for this, I have credited you in the source and will in any release its used in!
if you want it removed you can contact me on this post or hit me up [email protected]