[Winform Study Notes (7)] Winform borderless form drag function

Preface

This article mainly introduces how to set the form to borderless mode and several methods to realize the dragging function of borderless form.

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1. Set borderless mode

Select the form whose borders you want to remove, press F4 to bring up its properties panel, find FormBorderStyle in the properties panel , and select None to set the form to borderless mode; by default, it cannot be dragged at will and is not maximized. Minimize close button.

2. Borderless form dragging method

1. Implement form movement through Panel control

1. Implementation method : Add a Panel control at the head of the form, and move the form through the Panel's MouseDown and MouseMove events;

2. Implementation principle : directly modify the position of the form to achieve the effect of moving the form;

3. Specific code :

   		private Point mPoint;//定义一个位置信息Point用于存储鼠标位置
           /// <summary>
           /// 鼠标按下
           /// </summary>
           /// <param name="sender"></param>
           /// <param name="e"></param>
           private void uPanel1_MouseDown(object sender, MouseEventArgs e)
           {
         
         
               mPoint = new Point(e.X, e.Y);
           }
           /// <summary>
           /// 鼠标移动
           /// </summary>
           /// <param name="sender"></param>
           /// <param name="e"></param>
           private void uPanel1_MouseMove(object sender, MouseEventArgs e)
           {
         
         
               if (e.Button == MouseButtons.Left)
               {
         
         
                   this.Location = new Point(this.Location.X + e.X - mPoint.X, this.Location.Y + e.Y - mPoint.Y);
               }
           }
   

4. Realization effect :
   

2. Implement form movement through form events

1. Implementation method : realize form movement through the form MouseDown, MouseMove, and MouseUp events;

2. Specific code :

   		//通过窗体MouseDown、MouseMove、MouseUp事件实现窗体移动
           Point point; //鼠标按下时的点
           bool isMoving = false;//标识是否拖动
   
           private void Form1_MouseDown(object sender, MouseEventArgs e)
           {
         
         
               point = e.Location;//按下的点
               isMoving = true;//启动拖动
           }
   
           private void Form1_MouseMove(object sender, MouseEventArgs e)
           {
         
         
               if (e.Button == MouseButtons.Left && isMoving)
               {
         
         
                   Point pNew = new Point(e.Location.X - point.X, e.Location.Y - point.Y);
                   //Location = new Point(Location.X + pNew.X, Location.Y + pNew.Y);
                   Location += new Size(pNew);
               }
           }
   
           private void Form1_MouseUp(object sender, MouseEventArgs e)
           {
         
         
               isMoving = false;//停止
           }
   

3. Realization effect :
   

3. Call the system API to move the form

1. Implementation method : Use the Windows application programming interface Windows API to realize form movement;

2. Implementation principle : When the left mouse button is pressed, the system thinks it was pressed on the title bar;

3. Specific code :

   using System.Runtime.InteropServices;
           //调用系统API
           [DllImport("user32.dll")]
           public static extern bool ReleaseCapture();
           [DllImport("user32.dll")]
           public static extern bool SendMessage(IntPtr hwnd, int wMsg, int wParam, int lParam);
           private const int VM_NCLBUTTONDOWN = 0XA1;//定义鼠标左键按下
           public const int HTCAPTION = 0x0002; //HTCAPTION=2 鼠标在标题栏中
           /// <summary>
           /// 鼠标按下事件
           /// </summary>
           /// <param name="sender"></param>
           /// <param name="e"></param>
           private void Form1_MouseDown(object sender, MouseEventArgs e)
           {
         
         
               //为当前应用程序释放鼠标捕获
               ReleaseCapture();
               //发送消息 让系统误以为在标题栏上按下鼠标
               SendMessage((IntPtr)this.Handle, VM_NCLBUTTONDOWN, HTCAPTION, 0);
           }
   

4. Note : Need to introduce namespaceusing System.Runtime.InteropServices;

5. Realization effect :

4. Rewrite WndProc() to implement form movement

1. Implementation method : Implement form movement by overriding the WndProc() method;

2. Implementation principle : Change the message when the mouse is pressed in the client area to when the mouse is pressed in the title bar of the non-client area;

3. Specific code :

   		//重写WndProc：
           //原理：将鼠标在客户区按下的消息更改为在非客户区的标题栏按下
           protected override void WndProc(ref Message m)
           {
         
         
               switch (m.Msg)
               {
         
         
                   case 0x0201://鼠标左键按下的消息
                       m.Msg = 0x00A1;//更改消息为非客户区按下鼠标
                       m.LParam = IntPtr.Zero;//默认值
                       m.WParam = new IntPtr(2);//鼠标放在标题栏内
                       break;
               }
               base.WndProc(ref m);
           }
   

4. Realization effect :