using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.InteropServices;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace AIProofread
{
    /// <summary>
    /// 处理窗体基本事件
    /// </summary>
    [ClassInterface(ClassInterfaceType.AutoDual)]
    [ComVisible(true)]
    public class EventForwarder
    {
        public const int WM_NCLBUTTONDOWN = 0xA1;
        public const int HT_CAPTION = 0x2;

        [DllImport("user32.dll")]
        public static extern int SendMessage(IntPtr hWnd, int Msg, int wParam, int lParam);
        [DllImport("user32.dll")]
        public static extern bool ReleaseCapture();

        readonly IntPtr target;
        readonly Form formHandle;


        public EventForwarder(Form who)
        {
            this.target = who.Handle;
            this.formHandle = who;
        }

        public void Close()
        {
            formHandle.Close();
        }

        public void MouseDownDrag()
        {
            ReleaseCapture();
            SendMessage(target, WM_NCLBUTTONDOWN, HT_CAPTION, 0);
        }
    }
}