How to move and resize a form without a border?

Question

Does anyone know how I can resize a winform when it has no border. I don't want the default border that Windows has, so I changed the property "FormBorderStyle" to "None". This removed the border, although now it can't be resized. I've figured out how to move the form around, I just need to know how to resize it.

Answer 1

"Sizer" is the light blue panel in the right bottom corner enter image description here

    int Mx;
    int My;
    int Sw;
    int Sh;

    bool mov;

    void SizerMouseDown(object sender, MouseEventArgs e)
    {
        mov = true;
        My = MousePosition.Y;
        Mx = MousePosition.X;
        Sw = Width;
        Sh = Height;
    }

    void SizerMouseMove(object sender, MouseEventArgs e)
    {
        if (mov == true) {
            Width = MousePosition.X - Mx + Sw;
            Height = MousePosition.Y - My + Sh;
        }
    }

    void SizerMouseUp(object sender, MouseEventArgs e)
    {
        mov = false;
    }

Answer 2

(elaborate : in comment 2)

Resize "Form" From All place And Move it >>> Full Code <<<<<

//First u most to add this Class

 class ReSize
     {

        private bool Above, Right, Under, Left, Right_above, Right_under, Left_under, Left_above;


        int Thickness=6;  //Thickness of border  u can cheang it
        int Area = 8;     //Thickness of Angle border 


        /// <summary>
        /// Constructor
        /// </summary>
        /// <param name="thickness">set thickness of form border</param>
        public ReSize(int thickness)
        {
            Thickness = thickness;
        }

        /// <summary>
        /// Constructor set thickness of form border=1
        /// </summary>
        public ReSize()
        {
            Thickness = 10;
        }

        //Get Mouse Position
        public  string getMosuePosition(Point mouse, Form form)
        {
            bool above_underArea = mouse.X > Area && mouse.X < form.ClientRectangle.Width - Area; /* |\AngleArea(Left_Above)\(=======above_underArea========)/AngleArea(Right_Above)/| */ //Area===>(==)
            bool right_left_Area = mouse.Y > Area && mouse.Y < form.ClientRectangle.Height - Area; 

            bool _Above=mouse.Y <= Thickness;  //Mouse in Above All Area
            bool _Right= mouse.X >= form.ClientRectangle.Width - Thickness;
            bool _Under=mouse.Y >= form.ClientRectangle.Height - Thickness;
            bool _Left=mouse.X <= Thickness;

            Above = _Above && (above_underArea); if (Above) return "a";   /*Mouse in Above All Area WithOut Angle Area */
            Right = _Right && (right_left_Area); if (Right) return "r";
            Under = _Under && (above_underArea); if (Under) return "u";
            Left = _Left && (right_left_Area);   if (Left) return "l";


            Right_above =/*Right*/ (_Right && (!right_left_Area)) && /*Above*/ (_Above && (!above_underArea));   if (Right_above) return "ra";     /*if Mouse  Right_above */
            Right_under =/* Right*/((_Right) && (!right_left_Area)) && /*Under*/(_Under && (!above_underArea));  if (Right_under) return "ru";     //if Mouse  Right_under 
            Left_under = /*Left*/((_Left) && (!right_left_Area)) && /*Under*/ (_Under && (!above_underArea));    if (Left_under) return "lu";      //if Mouse  Left_under
            Left_above = /*Left*/((_Left) && (!right_left_Area)) && /*Above*/(_Above && (!above_underArea));     if (Left_above) return "la";      //if Mouse  Left_above

            return "";

        }


    }

Then Form cs

 public partial class FormGDI : Form
    {

        ReSize resize = new ReSize();     // ReSize Class "/\" To Help Resize Form <None Style>


        public FormGDI()
        {
            InitializeComponent();
            this.SetStyle(ControlStyles.ResizeRedraw, true);

        }


        private const int cGrip = 16;      // Grip size
        private const int cCaption = 32;   // Caption bar height;

        protected override void OnPaint(PaintEventArgs e)
        {
            //this if you want to draw   (if)

            Color theColor = Color.FromArgb(10, 20, 20, 20);
            theColor = Color.DarkBlue;
            int BORDER_SIZE = 4;
            ControlPaint.DrawBorder(e.Graphics, ClientRectangle,
                                         theColor, BORDER_SIZE, ButtonBorderStyle.Dashed,
                                         theColor, BORDER_SIZE, ButtonBorderStyle.Dashed,
                                         theColor, BORDER_SIZE, ButtonBorderStyle.Dashed,
                                         theColor, BORDER_SIZE, ButtonBorderStyle.Dashed);


            Rectangle rc = new Rectangle(this.ClientSize.Width - cGrip, this.ClientSize.Height - cGrip, cGrip, cGrip);
            ControlPaint.DrawSizeGrip(e.Graphics, this.BackColor, rc);
            rc = new Rectangle(0, 0, this.ClientSize.Width, cCaption);
            e.Graphics.FillRectangle(Brushes.DarkBlue, rc);



            base.OnPaint(e);
        }


        //set MinimumSize to Form
        public override Size MinimumSize
        {
            get
            {
                return base.MinimumSize;
            }
            set
            {
                base.MinimumSize = new Size(179, 51); 
            }
        }

        //
        //override  WndProc  
        //
        protected override void WndProc(ref Message m)
        {
            //****************************************************************************

            int x = (int)(m.LParam.ToInt64() & 0xFFFF);               //get x mouse position
            int y = (int)((m.LParam.ToInt64() & 0xFFFF0000) >> 16);   //get y mouse position  you can gave (x,y) it from "MouseEventArgs" too
            Point pt = PointToClient(new Point(x, y));

            if (m.Msg == 0x84)
            {
                switch (resize.getMosuePosition(pt, this))
                {
                    case "l": m.Result = (IntPtr)10; return;  // the Mouse on Left Form
                    case "r": m.Result = (IntPtr)11; return;  // the Mouse on Right Form
                    case "a": m.Result = (IntPtr)12; return;
                    case "la": m.Result = (IntPtr)13; return;
                    case "ra": m.Result = (IntPtr)14; return;
                    case "u": m.Result = (IntPtr)15; return;
                    case "lu": m.Result = (IntPtr)16; return;
                    case "ru": m.Result = (IntPtr)17; return; // the Mouse on Right_Under Form
                    case "": m.Result = pt.Y < 32 /*mouse on title Bar*/ ? (IntPtr)2 : (IntPtr)1; return;  

                }
            }

              base.WndProc(ref m);

        }

    }

Answer 3

Some sample code that allow moving and resizing the form:

  public partial class Form1 : Form {
    public Form1() {
      InitializeComponent();
      this.FormBorderStyle = FormBorderStyle.None;
      this.DoubleBuffered = true;
      this.SetStyle(ControlStyles.ResizeRedraw, true);
    }
    private const int cGrip = 16;      // Grip size
    private const int cCaption = 32;   // Caption bar height;

    protected override void OnPaint(PaintEventArgs e) {
      Rectangle rc = new Rectangle(this.ClientSize.Width - cGrip, this.ClientSize.Height - cGrip, cGrip, cGrip);
      ControlPaint.DrawSizeGrip(e.Graphics, this.BackColor, rc);
      rc = new Rectangle(0, 0, this.ClientSize.Width, cCaption);
      e.Graphics.FillRectangle(Brushes.DarkBlue, rc);
    }

    protected override void WndProc(ref Message m) {
      if (m.Msg == 0x84) {  // Trap WM_NCHITTEST
        Point pos = new Point(m.LParam.ToInt32());
        pos = this.PointToClient(pos);
        if (pos.Y < cCaption) {
          m.Result = (IntPtr)2;  // HTCAPTION
          return;
        }
        if (pos.X >= this.ClientSize.Width - cGrip && pos.Y >= this.ClientSize.Height - cGrip) {
          m.Result = (IntPtr)17; // HTBOTTOMRIGHT
          return;
        }
      }
      base.WndProc(ref m);
    }
  }

Answer 4

The simplest way is to assign mouse events to the form or the title bar, whatever you want to be hold for moving. You can move a BorderLess Form with assigning these methods to there events as names in method.

    int movX;
    int moxY;
    bool isMoving;

    private void onMouseDown(object sender, MouseEventArgs e)  
    {
         // Assign this method to mouse_Down event of Form or Panel,whatever you want
        isMoving = true;
        movX = e.X;
        movY = e.Y;
    }

    private void onMouseMove(object sender, MouseEventArgs e)
    {
         // Assign this method to Mouse_Move event of that Form or Panel
        if (isMoving)
        {
            this.SetDesktopLocation(MousePosition.X - movX, MousePosition.Y - movY);
        }
    }

    private void onMouseUp(object sender, MouseEventArgs e)
    {
       // Assign this method to Mouse_Up event of Form or Panel.
        isMoving = false;
    }

Answer 5

Here's a complete example of a customized form with all 8 points of resizing:

public partial class Form1 : Form {
public Form1() {
  InitializeComponent();
  this.FormBorderStyle = FormBorderStyle.None; // no borders
  this.DoubleBuffered = true;
  this.SetStyle(ControlStyles.ResizeRedraw, true); // this is to avoid visual artifacts
}

protected override void OnPaint(PaintEventArgs e) // you can safely omit this method if you want
{
    e.Graphics.FillRectangle(Brushes.Green, Top);
    e.Graphics.FillRectangle(Brushes.Green, Left);
    e.Graphics.FillRectangle(Brushes.Green, Right);
    e.Graphics.FillRectangle(Brushes.Green, Bottom);
}

private const int
    HTLEFT = 10,
    HTRIGHT = 11,
    HTTOP = 12,
    HTTOPLEFT = 13,
    HTTOPRIGHT = 14,
    HTBOTTOM = 15,
    HTBOTTOMLEFT = 16,
    HTBOTTOMRIGHT = 17;

const int _ = 10; // you can rename this variable if you like

Rectangle Top { get { return new Rectangle(0, 0, this.ClientSize.Width, _); } }
Rectangle Left { get { return new Rectangle(0, 0, _, this.ClientSize.Height); } }
Rectangle Bottom { get { return new Rectangle(0, this.ClientSize.Height - _, this.ClientSize.Width, _); } }
Rectangle Right { get { return new Rectangle(this.ClientSize.Width - _, 0, _, this.ClientSize.Height); } }

Rectangle TopLeft { get { return new Rectangle(0, 0, _, _); } }
Rectangle TopRight { get { return new Rectangle(this.ClientSize.Width - _, 0, _, _); } }
Rectangle BottomLeft { get { return new Rectangle(0, this.ClientSize.Height - _, _, _); } }
Rectangle BottomRight { get { return new Rectangle(this.ClientSize.Width - _, this.ClientSize.Height - _, _, _); } }


protected override void WndProc(ref Message message)
{
    base.WndProc(ref message);

    if (message.Msg == 0x84) // WM_NCHITTEST
    {
        var cursor = this.PointToClient(Cursor.Position);

        if (TopLeft.Contains(cursor)) message.Result = (IntPtr)HTTOPLEFT;
   else if (TopRight.Contains(cursor)) message.Result = (IntPtr)HTTOPRIGHT;
   else if (BottomLeft.Contains(cursor)) message.Result = (IntPtr)HTBOTTOMLEFT;
   else if (BottomRight.Contains(cursor)) message.Result = (IntPtr)HTBOTTOMRIGHT;

   else if (Top.Contains(cursor)) message.Result = (IntPtr)HTTOP;
   else if (Left.Contains(cursor)) message.Result = (IntPtr)HTLEFT;
   else if (Right.Contains(cursor)) message.Result = (IntPtr)HTRIGHT;
   else if (Bottom.Contains(cursor)) message.Result = (IntPtr)HTBOTTOM;
    }
}}