Code Sharing for drag and zoom implementations of WinForm controls in C #

This article mainly introduces the implementation code of drag and scale of WinForm control in C #, and the drag and zoom of C # WinForm control is a useful function, which is interesting to understand.

The drag and scale of the C # WinForm control is a useful feature. Implementation is actually very simple, mainly the design of the control MouseDown, MouseLeave, MouseMove events, the following steps will gradually implement the C # WinForm control of the drag and zoom function.

1. Define an enumeration type that describes the cursor state

Private enum enummousepointposition    {    Mousesizenone  = 0,//' no    mousesizeright  = 1,//' Extrude right    border Mousesizeleft  = 2,//' Extrude left border    mousesizebottom  = 3,//' Extrude bottom frame    mousesizetop  = 4,//' Extrude top Border    Mousesizetopleft = 5,//' Extrude upper left corner    mousesizetopright = 6,//' Extrude upper right corner    Mousesizebottomleft = 7,//' extrude lower left corner    Mousesizebottomright= 8,//' stretched lower right corner    mousedrag  = 9  //' Mouse drag    }

2. Define several variables

const int Band = 5;    const int minwidth=10;    const int minheight=10;    Private Enummousepointposition m_mousepointposition;    Private point P,p1;

3. Define your own Mymousedown events

private void Mymousedown (Object Sender,system.windows.forms.mouseeventargs e)  {   p.x=e.x;   P.y=e.y;   P1. x=e.x;   P1. y=e.y;    }

4. Define your own Mymouseleave events

private void Mymouseleave (object sender, System.EventArgs e)  {   m_mousepointposition = Enummousepointposition.mousesizenone;   This. Cursor=cursors.arrow;  }

5. Design a function to determine the style of the cursor at different positions in the control

Private Enummousepointposition mousepointposition (Size Size,system.windows.forms.mouseeventargs e) {if (E.X >=- 1 * Band) | (e.x <= size.) Width) | (E.y >=-1 * Band) | (e.y <= size.)    Height) {if (E.x < Band) {if (E.y < Band) {return enummousepointposition.mousesizetopleft;} else {if (E.y >-1 * Band + size.    Height) {return enummousepointposition.mousesizebottomleft;}    else {return enummousepointposition.mousesizeleft;} }} else {if (e.x >-1 * Band + size.    Width) {if (E.y < Band) {return enummousepointposition.mousesizetopright;} else {if (E.y >-1 * Band + size.     Height) {return enummousepointposition.mousesizebottomright;}    else {return enummousepointposition.mousesizeright;}    }} else {if (E.y < Band) {return enummousepointposition.mousesizetop;} else {if (E.y >-1 * Band + size. Height) {return enummousepointposition.mousesizebottom;} else {return enummousepointposition.mousedrag;}  }}}} else {return enummousepointposition.mousesizenone;} }

6. Define your own Mymousemove event, in which the function designed above will be used

  private void Mymousemove (Object Sender,system.windows.forms.mouseeventargs e) {Control Lctrl = (sender as Control)      ;         if (e.button==mousebuttons.left) {switch (m_mousepointposition) {case Enummousepointposition.mousedrag:      Lctrl.left =lctrl.left+ e.x-p.x;      Lctrl.top =lctrl.top+ e.y-p.y;     Break Case EnumMousePointPosition.MouseSizeBottom:lCtrl.Height = Lctrl.height + e.y-p1.      Y P1.      x=e.x; P1. Y=e.y;     ' Record cursor to drag the current point to break; Case EnumMousePointPosition.MouseSizeBottomRight:lCtrl.Width = Lctrl.width + e.x-p1.      X Lctrl.height = Lctrl.height + e.y-p1.      Y P1.      x=e.x; P1. Y=e.y;     ' Record cursor to drag the current point to break; Case EnumMousePointPosition.MouseSizeRight:lCtrl.Width = Lctrl.width + e.x-p1.     X Lctrl.height = Lctrl.height + e.y-p1.      Y P1.      x=e.x; P1. Y=e.y;     ' Record cursor to drag the current point to break;      Case EnumMousePointPosition.MouseSizeTop:lCtrl.Top = lctrl.top + (E.Y-P.Y); Lctrl.Height = Lctrl.height-(E.Y-P.Y);     Break      Case EnumMousePointPosition.MouseSizeLeft:lCtrl.Left = Lctrl.left + e.x-p.x;      Lctrl.width = Lctrl.width-(e.x-p.x);     Break      Case EnumMousePointPosition.MouseSizeBottomLeft:lCtrl.Left = Lctrl.left + e.x-p.x;      Lctrl.width = Lctrl.width-(e.x-p.x); Lctrl.height = lctrl.height+ E.y-p1.      Y P1.      x=e.x; P1. Y=e.y;     ' Record cursor to drag the current point to break;      Case EnumMousePointPosition.MouseSizeTopRight:lCtrl.Top = lctrl.top + (E.Y-P.Y); Lctrl.width = Lctrl.width + (e.x-p1.      X);      Lctrl.height = Lctrl.height-(E.Y-P.Y); P1.      x=e.x; P1. Y=e.y;     ' Record cursor to drag the current point to break;      Case EnumMousePointPosition.MouseSizeTopLeft:lCtrl.Left = Lctrl.left + e.x-p.x;      Lctrl.top = Lctrl.top + (E.Y-P.Y);      Lctrl.width = Lctrl.width-(e.x-p.x);      Lctrl.height = Lctrl.height-(E.Y-P.Y);     Break     Default:break; } if (Lctrl.width<minwidth) lctrL.width=minwidth;         if (lctrl.height<minheight) lctrl.height=minheight;  } else {m_mousepointposition = Mousepointposition (Lctrl.size, E); ' Determine the cursor position status switch (m_mousepointposition)//' Change cursor {case EnumMousePointPosition.MouseSizeNone:this.    Cursor = Cursors.arrow;     ' Arrow break; Case EnumMousePointPosition.MouseDrag:this.   Cursor = Cursors.sizeall;     ' Quartet to break; Case EnumMousePointPosition.MouseSizeBottom:this.    Cursor = Cursors.sizens;     ' North-South break; Case EnumMousePointPosition.MouseSizeTop:this.    Cursor = Cursors.sizens;     ' North-South break; Case EnumMousePointPosition.MouseSizeLeft:this.    Cursor = Cursors.sizewe;     ' Something break; Case EnumMousePointPosition.MouseSizeRight:this.    Cursor = Cursors.sizewe;     ' Something break; Case EnumMousePointPosition.MouseSizeBottomLeft:this.   Cursor = CURSORS.SIZENESW;     ' Northeast to south West break; Case Enummousepointposition.mousesizebottoMright:this.   Cursor = Cursors.sizenwse;     ' Southeast to Northwest break; Case EnumMousePointPosition.MouseSizeTopLeft:this.   Cursor = Cursors.sizenwse;     ' Southeast to Northwest break; Case EnumMousePointPosition.MouseSizeTopRight:this.   Cursor = CURSORS.SIZENESW;     ' Northeast to south West break;     Default:break; }    }      }

7. Make an initialization process, bind all the controls on the interface Panel1 to Mymousedown, Mymouseleave, Mymousemove events, and remember to execute it first when the form is initialized or Form_Load.

private void Initproperty ()  {for   (int i = 0; i < This.panel1.Controls.Count; i++)    {    This.panel1.controls[i]. mousedown+= new System.Windows.Forms.MouseEventHandler (Mymousedown);   This.panel1.controls[i]. mouseleave+= new System.EventHandler (mymouseleave);   This.panel1.controls[i]. MouseMove + = new System.Windows.Forms.MouseEventHandler (mymousemove);   }    }

8, OK, before running you put a few controls on the Panel1, execute the program, should be able to casually move, change its size

The implementation of drag and zoom for the C # WinForm control is complete.