// 要嵌入窗体的句柄
IntPtr wnd = Cocos2dxEditor.Cocos2dx.Cocos2dxNativeInterface.GetCocosWindow();
// 嵌入窗体
FormEmbedder.EmbedWindow(wnd, this.panel1);

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

    [DllImport("user32.dll", SetLastError = true)]
    private static extern IntPtr GetWindowLong(IntPtr hWnd, int nIndex);

    [DllImport("user32.dll", SetLastError = true)]
    private static extern IntPtr SetWindowLong(IntPtr hWnd, int nIndex, IntPtr dwNewLong);

    [DllImport("user32.dll", SetLastError = true)]
    private static extern bool MoveWindow(IntPtr hWnd, int X, int Y, int nWidth, int nHeight, bool bRepaint);

    private const int GWL_STYLE = -16;
    private const int WS_BORDER = 0x00800000;
    private const int WS_CAPTION = 0x00C00000;

    public static void EmbedWindow(IntPtr childPtr, Control parent)
    {
        // 去除子窗口边框
        IntPtr style = GetWindowLong(childPtr, GWL_STYLE);
        style = (IntPtr)((int)style & ~WS_BORDER & ~WS_CAPTION);
        SetWindowLong(childPtr, GWL_STYLE, style);

        // 设置子窗口的父窗口
        SetParent(childPtr, parent.Handle);

        // 调整子窗口的大小和位置
        MoveWindow(childPtr, 0, 0, parent.Width, parent.Height, true);

        // 在调整父控件大小时，调整子窗口大小
        parent.SizeChanged += (s, e) =>
        {
            MoveWindow(childPtr, 0, 0, parent.Width, parent.Height, true);
        };
    }
}