WinForm特效:拦截窗体上各个部位的点击

windows窗体的标题栏无法直接通过一些默认的事件来控制，需要了解和WM_NCHITTEST相关的windows消息。 以下示例演示了最简单的效果片断： 他会把客户区和标题栏的效果互换，比如无法按住标题栏拖动窗体而是改为了安抓客户区拖动，并禁用了关闭按钮。 其中m.Result从-2到21都有定义，分别度应了整个窗体的各个部位，比如1代表客户区，8代表最小化按钮等等。

using System;

using System.Windows.Forms;

namespace WindowsApplication42

{

    public partial class Form1 : Form

    {

        public Form1() { InitializeComponent(); this.Text = "双击左上角图标关闭窗体"; }

        //拦击标题栏鼠标位置事件  

        const int WM_NCHITTEST = 0x84;

        protected override void WndProc(ref Message m)

        {

            base.WndProc(ref m); if (m.Msg == WM_NCHITTEST)

            {

                switch (m.Result.ToInt32())

                {

                    case 1://客户区  

                        m.Result = new IntPtr(2); break;

                    case 2://标题栏  

                        m.Result = new IntPtr(1); break;

                    case 20: m.Result = new IntPtr(0); break;

                    default: Console.WriteLine(m); break;

                }

            }

        }

    }

}

下面是各个常量的意义：从Delphi7 VCL中摘取：

{ WM_NCHITTEST and MOUSEHOOKSTRUCT Mouse Position Codes }

  {$EXTERNALSYM HTERROR}

  HTERROR = -2;

  {$EXTERNALSYM HTTRANSPARENT}

  HTTRANSPARENT = -1;

  {$EXTERNALSYM HTNOWHERE}

  HTNOWHERE = 0;

  {$EXTERNALSYM HTCLIENT}

  HTCLIENT = 1;

  {$EXTERNALSYM HTCAPTION}

  HTCAPTION = 2;

  {$EXTERNALSYM HTSYSMENU}

  HTSYSMENU = 3;

  {$EXTERNALSYM HTGROWBOX}

  HTGROWBOX = 4;

  {$EXTERNALSYM HTSIZE}

  HTSIZE = HTGROWBOX;

  {$EXTERNALSYM HTMENU}

  HTMENU = 5;

  {$EXTERNALSYM HTHSCROLL}

  HTHSCROLL = 6;

  {$EXTERNALSYM HTVSCROLL}

  HTVSCROLL = 7;

  {$EXTERNALSYM HTMINBUTTON}

  HTMINBUTTON = 8;

  {$EXTERNALSYM HTMAXBUTTON}

  HTMAXBUTTON = 9;

  {$EXTERNALSYM HTLEFT}

  HTLEFT = 10;

  {$EXTERNALSYM HTRIGHT}

  HTRIGHT = 11;

  {$EXTERNALSYM HTTOP}

  HTTOP = 12;

  {$EXTERNALSYM HTTOPLEFT}

  HTTOPLEFT = 13;

  {$EXTERNALSYM HTTOPRIGHT}

  HTTOPRIGHT = 14;

  {$EXTERNALSYM HTBOTTOM}

  HTBOTTOM = 15;

  {$EXTERNALSYM HTBOTTOMLEFT}

  HTBOTTOMLEFT = 16;

  {$EXTERNALSYM HTBOTTOMRIGHT}

  HTBOTTOMRIGHT = 17;

  {$EXTERNALSYM HTBORDER}

  HTBORDER = 18;

  {$EXTERNALSYM HTREDUCE}

  HTREDUCE = HTMINBUTTON;

  {$EXTERNALSYM HTZOOM}

  HTZOOM = HTMAXBUTTON;

  {$EXTERNALSYM HTSIZEFIRST}

  HTSIZEFIRST = HTLEFT;

  {$EXTERNALSYM HTSIZELAST}

  HTSIZELAST = HTBOTTOMRIGHT;

  {$EXTERNALSYM HTOBJECT}

  HTOBJECT = 19;

  {$EXTERNALSYM HTCLOSE}

  HTCLOSE = 20;

  {$EXTERNALSYM HTHELP}

  HTHELP = 21;