C # custom drag and resize methods for controls

When using the Form Designer of Vs, we can find that the control can be dragged and the size can be adjusted. How can I use the above functions in my own program? The following method is worth learning!

Using system; <br/> using system. windows. forms; <br/> using system. drawing; <br/> namespace controlsizechangeex <br/> {<br/> /// <summary> <br/> // This class implements sizing and moving functions for <br/> /// runtime editing of graphic controls <br/> /// </Summary> <br/> public class pickbox <br/>{< br/> ///// //////////////////////////////////////// /// // <br/> // Private Constants And variables <br/> ////////////////////////////////// /// // <br/> private const int box_size = 8; <br/> private color box_color = color. white; <br/> private containercontrol m_container; <br/> private control m_control; <br/> private label [] LBL = new label [8]; <br/> private int startl; <br/> private int startt; <br/> private int startw; <br/> private int starth; <br/> Private int startx; <br/> private int starty; <br/> private bool dragging; <br/> private cursor [] arrarrow = new cursor [] {cursors. sizenwse, cursors. sizens, <br/> cursors. sizenesw, cursors. sizewe, cursors. sizenwse, cursors. sizens, <br/> cursors. sizenesw, cursors. sizewe }; <br/> private cursor oldcursor; <br/> private const int min_size = 20; <br/> // constructor creates 8 sizing handles & Wires mouse events <br/> // to each that implement sizing functions <br/> // <br/> Public pickbox () <br/> {<br/> for (INT I = 0; I <8; I ++) <br/>{< br/> LBL [I] = new label (); <br/> LBL [I]. tabindex = I; <br/> LBL [I]. flatstyle = 0; <br/> LBL [I]. borderstyle = borderstyle. fixedsingle; <br/> LBL [I]. backcolor = box_color; <br/> LBL [I]. cursor = arrarrow [I]; <br/> LBL [I]. TEXT = ""; <br/> LBL [I]. bringto Front (); <br/> LBL [I]. mousedown + = new mouseeventhandler (this. lbl_mousedown); <br/> LBL [I]. mousemove + = new mouseeventhandler (this. lbl_mousemove); <br/> LBL [I]. mouseup + = new mouseeventhandler (this. lbl_mouseup ); <br/>}< br/> ////////////////////////// //////////////////////////////////////// <br/> // public methods <br/> //////////////////////////// /// // <br />/< Br/> // wires a click event handler to the passed Control <br/> // that attaches a pick box to the control when it is clicked <br/> // <br/> Public void wirecontrol (control CTL) <br/>{< br/> CTL. click + = new eventhandler (this. selectcontrol ); <br/>}< br/> /////////////////////////////// /// // <br/> // private methods <br/> ////////////////////////////////// //// /// // <Br/> // attaches A pick box to the sender Control <br/> // <br/> private void selectcontrol (Object sender, eventargs e) <br/>{< br/> If (m_control is control) <br/>{< br/> m_control.cursor = oldcursor; <br/> // remove event any pre-existing Event Handlers appended by this class <br/> m_control.mousedown-= new mouseeventhandler (this. ctl_mousedown); <br/> m_co Ntrol. mousemove-= new mouseeventhandler (this. ctl_mousemove); <br/> m_control.mouseup-= new mouseeventhandler (this. ctl_mouseup); <br/> m_control = NULL; <br/>}< br/> m_control = (Control) sender; <br/> // Add Event Handlers for moving the selected control around <br/> m_control.mousedown + = new mouseeventhandler (this. ctl_mousedown); <br/> m_control.mousemove + = new mouseeventhandler (this. ctl_mouse Move); <br/> m_control.mouseup + = new mouseeventhandler (this. ctl_mouseup); <br/> // Add sizing handles to control's container (Form or picturebox) <br/> for (INT I = 0; I <8; I ++) <br/>{< br/> m_control.parent.controls.add (LBL [I]); <br/> LBL [I]. bringtofront (); <br/>}< br/> // position sizing handles around Control <br/> movehandles (); <br/> // display sizing handles <br/> showhandles (); <br/> oldc Ursor = m_control.cursor; <br/> m_control.cursor = cursors. sizeall; <br/>}< br/> Public void remove () <br/>{< br/> hidehandles (); <br/> m_control.cursor = oldcursor; <br/>}< br/> private void showhandles () <br/>{< br/> If (m_control! = NULL) <br/>{< br/> for (INT I = 0; I <8; I ++) <br/> {<br/> LBL [I]. visible = true; <br/>}< br/> private void hidehandles () <br/> {<br/> for (INT I = 0; I <8; I ++) <br/> {<br/> LBL [I]. visible = false; <br/>}< br/> private void movehandles () <br/>{< br/> int SX = m_control.left-box_size; <br/> int Sy = m_control.top-box_size; <br/> int Sw = m_control.width + box _ Size; <br/> int SH = m_control.height + box_size; <br/> int HB = box_size/2; <br/> int [] arrposx = new int [] {SX + HB, SX + Sw/2, SX + Sw-Hb, SX + Sw-Hb, <br/> SX + Sw-Hb, SX + Sw/2, SX + HB, SX + HB }; <br/> int [] arrposy = new int [] {SY + HB, SY + sh/2, SY + sh-Hb, <br/> SY + sh-Hb, SY + sh-Hb, SY + sh/2}; <br/> for (INT I = 0; I <8; I ++) <br/> LBL [I]. setbounds (arrposx [I], arrpos Y [I], box_size, box_size ); <br/>}< br/> /////////////////////////////// /// // <br/> // mouse events that implement sizing of the picked Control <br/> /////////////////////////// /// // <br />/< br/> // store control position and size when mouse button pushed over <br/> // any sizing handle <br/> // <br/> private void lbl_mousedown (Object Sender, mouseeventargs e) <br/>{< br/> dragging = true; <br/> startl = m_control.left; <br/> startt = m_control.top; <br/> startw = m_control.width; <br/> starth = m_control.height; <br/> hidehandles (); <br/>}< br/> // <br/> // size the picked control in accordance with Sizing handle being dragged <br/> // 0 1 2 <br/> // 7 3 <br/> // 6 5 4 <br/> // <br/> private void lbl_mousemove (Object sender, Mouseeventargs e) <br/>{< br/> int L = m_control.left; <br/> int W = m_control.width; <br/> int T = m_control.top; <br/> int H = m_control.height; <br/> If (dragging) <br/> {<br/> switch (Label) sender ). tabindex) <br/>{< br/> case 0: // dragging top-left Sizing Box <br/> L = startl + E. x <startl + startw-min_size? Startl + E. X: startl + startw-min_size; <br/> T = startt + E. Y <startt + starth-min_size? Startt + E. y: startt + starth-min_size; <br/> W = startl + startw-m_control.left; <br/> H = startt + starth-m_control.top; <br/> break; <br/> case 1: // dragging top-center Sizing Box <br/> T = startt + E. Y <startt + starth-min_size? Startt + E. y: startt + starth-min_size; <br/> H = startt + starth-m_control.top; <br/> break; <br/> case 2: // dragging top-Right Sizing Box <br/> W = startw + E. x> min_size? Startw + E. X: min_size; <br/> T = startt + E. Y <startt + starth-min_size? Startt + E. y: startt + starth-min_size; <br/> H = startt + starth-m_control.top; <br/> break; <br/> case 3: // dragging right-middle Sizing Box <br/> W = startw + E. x> min_size? Startw + E. x: min_size; <br/> break; <br/> case 4: // dragging right-bottom Sizing Box <br/> W = startw + E. x> min_size? Startw + E. X: min_size; <br/> H = starth + E. Y> min_size? Starth + E. y: min_size; <br/> break; <br/> case 5: // dragging center-bottom Sizing Box <br/> H = starth + E. y> min_size? Starth + E. y: min_size; <br/> break; <br/> case 6: // dragging left-bottom Sizing Box <br/> L = startl + E. x <startl + startw-min_size? Startl + E. X: startl + startw-min_size; <br/> W = startl + startw-m_control.left; <br/> H = starth + E. Y> min_size? Starth + E. y: min_size; <br/> break; <br/> case 7: // dragging left-middle Sizing Box <br/> L = startl + E. x <startl + startw-min_size? Startl + E. x: startl + startw-min_size; <br/> W = startl + startw-m_control.left; <br/> break; <br/>}< br/> L = (L <0 )? 0: L; <br/> T = (T <0 )? 0: T; <br/> m_control.setbounds (L, t, W, H ); <br/>}< br/> // <br/> // display sizing handles around picked control once sizing has completed <br/> // <br /> private void lbl_mouseup (Object sender, mouseeventargs e) <br/>{< br/> dragging = false; <br/> movehandles (); <br/> showhandles (); <br/>}< br/> /////////////////////////////// /// // <br/> // mouse events That move the picked control around the form <br/> //////////////////////////// /// // <br/> // <br/> // get mouse pointer starting position on mouse down and hide sizing handles <br/> // <br/> private void ctl_mousedown (Object sender, mouseeventargs e) <br/>{< br/> dragging = true; <br/> startx = E. x; <br/> starty = E. y; <br/> hidehandles (); <br/>}< br/> // <br/>/ /Reposition the dragged Control <br/> // <br/> private void ctl_mousemove (Object sender, mouseeventargs e) <br/>{< br/> If (dragging) <br/>{< br/> int L = m_control.left + E. x-startx; <br/> int T = m_control.top + E. y-starty; <br/> int W = m_control.width; <br/> int H = m_control.height; <br/> L = (L <0 )? 0: (L + W> m_control.parent.clientrectangle.width )? <Br/> m_control.parent.clientrectangle.width-W: l); <br/> T = (T <0 )? 0: (t + H> m_control.parent.clientrectangle.height )? <Br/> m_control.parent.clientrectangle.height-H: T); <br/> m_control.left = L; <br/> m_control.top = T; <br/>}< br/> // <br/> // display sizing handles around picked control once dragging has completed <br/> // <br /> private void ctl_mouseup (Object sender, mouseeventargs e) <br/>{< br/> dragging = false; <br/> movehandles (); <br/> showhandles (); <br/>}< br/> 

 

Create a pickbox object and call the wirecontrol of this object (the control you want to change). The method is fine.