C# 将Windows窗体附加到Unity3D制作的游戏

它适用于其他winform程序，但不适用于游戏本身。 我试图制作一个额外的菜单或“mod menu”，但它是不可见的

用于测试winform是否工作的消息框按钮。当我点击左上角的

“无处”

时，它会在消息框中显示

“hello”

我试图编辑代码，但找不到问题。我该怎么办

namespace myapp
{

public partial class Form1 : Form
{
    [System.ComponentModel.Browsable(false)]
    public bool AllowTransparency { get; set; }

    [System.ComponentModel.Browsable(false)]
    public bool AllowTransparencykey { get; set; }

    [DllImport("user32.dll")]
    public static extern int SetWindowLong(IntPtr hWnd, int nIndex, int dwNewLong);

    [DllImport("user32.dll")]
    public static extern int GetWindowLong(IntPtr hWnd, int nIndex);

    [DllImport("user32.dll", SetLastError = true)]
    private static extern IntPtr SetParent(IntPtr hWndChild, IntPtr hWndNewParent);

    public static int GWL_STYLE = -16;
    public static int WS_CHILD = 0x40000000;

    public Form1()
    {
        InitializeComponent();

    }

    private void Form1_Load(object sender, EventArgs e)
    {

    }

    private void button1_Click(object sender, EventArgs e)
    {
        Process hostProcess = Process.GetProcessesByName("game").FirstOrDefault();
        if (hostProcess != null)
        {
            Hide();
            FormBorderStyle = FormBorderStyle.None;
            SetBounds(0, 0, 0, 0, BoundsSpecified.Location);

            IntPtr hostHandle = hostProcess.MainWindowHandle;
            IntPtr guestHandle = this.Handle;
            SetWindowLong(guestHandle, GWL_STYLE, GetWindowLong(guestHandle, GWL_STYLE) | WS_CHILD);
            SetParent(guestHandle, hostHandle);
            Show();
            FormBorderStyle = FormBorderStyle.None;
            SetBounds(0, 0, 0, 0, BoundsSpecified.Location);
        }

    }

    private void button2_Click(object sender, EventArgs e)
    {
        MessageBox.Show("Hello");
    }
}
}