When using parentHWND option, keyboard input doesn't work

Unity Engine
1

I’ve been testing the new parentHWND command line option that appeared in 4.5.5p1 using the reference example provided in the documentation page, but when I tried to use Input.GetKey it never triggered. Input.GetMouseButton works correctly, but I couldn’t get keyboard input to work. I’ve tested it in Windows 8.1 x64 and Windows 7 x64.
I know is a very recent feature, but it looked great and I’d love to use it.
Any advice?

2

I have the same problem, mouse input works fine, but no keyboard input at all.
Did you find a solution or workaround for this?
Any official statement about this? Is it a bug, or missing something from the initialization on opener side?

3

I think you need to send WM_ACTIVATE

1 Like
4

Adding to Dave answer, here’s the updated Form1.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading;
using System.Windows.Forms;
using System.Diagnostics;
using System.Windows.Forms.VisualStyles;

namespace Container
{
    public partial class Form1 : Form
    {
        [DllImport("User32.dll")]
        static extern bool MoveWindow(IntPtr handle, int x, int y, int width, int height, bool redraw);

        internal delegate int WindowEnumProc(IntPtr hwnd, IntPtr lparam);
        [DllImport("user32.dll")]
        internal static extern bool EnumChildWindows(IntPtr hwnd, WindowEnumProc func, IntPtr lParam);

        [DllImport("user32.dll")]
        static extern int SendMessage(IntPtr hWnd, int msg, int wParam, uint lParam);

        private Process process;
        private IntPtr unityHWND = IntPtr.Zero;

        private const int WM_ACTIVATE = 0x0006;
        private const int WA_ACTIVE = 1;

        public Form1()
        {
            InitializeComponent();

            try
            {
                process = new Process();
                process.StartInfo.FileName = "Child.exe";
                process.StartInfo.Arguments = "-parentHWND " + panel1.Handle.ToInt32() + " " + Environment.CommandLine;
                process.StartInfo.UseShellExecute = true;
                process.StartInfo.CreateNoWindow = true;

                process.Start();

                process.WaitForInputIdle();
                // Doesn't work for some reason ?!
                //unityHWND = process.MainWindowHandle;
                EnumChildWindows(panel1.Handle, WindowEnum, IntPtr.Zero);

                unityHWNDLabel.Text = "Unity HWND: 0x" + unityHWND.ToString("X8");
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message + ".\nCheck if Container.exe is placed next to Child.exe.");
            }

        }
        private int WindowEnum(IntPtr hwnd, IntPtr lparam)
        {
            unityHWND = hwnd;
            SendMessage(unityHWND, WM_ACTIVATE, WA_ACTIVE, 0);
            return 0;
        }

        private void panel1_Resize(object sender, EventArgs e)
        {
            MoveWindow(unityHWND, 0, 0, panel1.Width, panel1.Height, true);
            SendMessage(unityHWND, WM_ACTIVATE, WA_ACTIVE, 0);
        }

        // Close Unity application
        private void Form1_FormClosed(object sender, FormClosedEventArgs e)
        {
            try
            {
                process.CloseMainWindow();

                Thread.Sleep(1000);
                while (process.HasExited == false)
                    process.Kill();
            }
            catch (Exception)
            {
               
            }
        }
    }
}
5 Likes
5

Can you plz guide me how to pass data to the embedded Unity Exe from the Host WPF Application ?

6

use Interprocess communication

7

I had similar issue, this was caused by the line

unityHWND = process.MainWindowHandle;

I dont know why I uncommented it. Removed the line, works well.

8

Still looking for a solution for this with the new input system. If anyone have one.

9

See https://discussions.unity.com/t/807093