在前面的文章中，提到過在vb.net中實現picturebox中圖片拖動，以及控件數組方面的東西。

因為項目需要，我要實現的是，圖片上有各個站點的名稱，我要實現點擊相應的名稱，進入站點，查看相應的信息。我采取的是在圖片上放一系列的label，然后點擊label，進入相應的站點，這樣就遇到了一個問題，要實現在拖動圖片的同時，所有的label也同步拖動。

下面的代碼實現了這個功能：

imports system.drawing
namespace winform.main
    public class mainwindow
        inherits system.windows.forms.form

---- " windows 窗體設計器生成的代碼 "---

 public sub new()
            mybase.new()

            '該調用是 windows 窗體設計器所必需的。
            initializecomponent()

            '在 initializecomponent() 調用之后添加任何初始化
            me.windowstate = windows.forms.formwindowstate.maximized
            loadtree()
            me.l_user_content.text = myform.loginuser.get_username
            '得到picturebox的初始位置坐標
            me.m_leftx = me.picturebox1.location.x
            me.m_lefty = me.picturebox1.location.y
            '得到圖片的縮放率
            me.m_strecthx = me.picturebox1.image.size.width / me.picturebox1.size.width
            me.m_strecthy = me.picturebox1.image.size.height / me.picturebox1.size.height

            '添加label雙擊的綁定
            bindarray()
        end sub

------------- windows 窗體設計器生成的代碼----------------------

   '處理圖片拖動

        private m_leftx as integer = 152
        private m_lefty as integer = 0
        dim m_mouseposx as integer
        dim m_mouseposy as integer
        dim m_driftx as integer
        dim m_drifty as integer
        '縮放率
        dim m_strecthx as double
        dim m_strecthy as double
        'label起始相對于picturebox的位置
        dim m_l_gw_ry_x as integer
        dim m_l_gw_ry_y as integer

        dim m_l_station_zf_x as integer
        dim m_l_station_zf_y as integer
        '是否第一次縮放
        dim m_l_first as boolean = true
        '處理label
        dim labels as new common.labelarray(me)

   '當鼠標按下時，將鼠標變成手形，并且記錄下當前鼠標的位置
        private sub picturebox1_mousedown(byval sender as object, byval e as system.windows.forms.mouseeventargs) handles picturebox1.mousedown           

            me.cursor = system.windows.forms.cursors.hand
            m_mouseposx = e.x
            m_mouseposy = e.y

           getlabelpositon()

 end sub

'根據偏移量計算出的圖片位置，重畫圖片
        private sub picturemove(byval sender as object, byval e as system.windows.forms.mouseeventargs)
            dim mybit as new system.drawing.bitmap(picturebox1.image)

            dim mypicgrh as system.drawing.graphics = me.picturebox1.creategraphics
            mypicgrh.clear(me.picturebox1.backcolor)
                        mypicgrh.drawimageunscaled(mybit, m_leftx - 152, m_lefty)
            stretchlabel()
            mybit.dispose()
            mypicgrh.dispose()

        end sub

  '處理鼠標按鍵抬起的事件，根據鼠標按下時保存的鼠標位置，和當前鼠標的位置，計算鼠標移動偏移量，借此調用移動圖片的函數，移動圖片
        private sub picturebox1_mouseup(byval sender as object, byval e as system.windows.forms.mouseeventargs) handles picturebox1.mouseup
            m_driftx = m_mouseposx - e.x
            m_drifty = m_mouseposy - e.y
            m_leftx = m_leftx - m_driftx
            m_lefty = m_lefty - m_drifty
            picturemove(sender, e)
            me.cursor = system.windows.forms.cursors.arrow

        end sub

   '將管網圖上的站點的label用一個事件來處理，處理之前需要綁定
        public sub bindarray()
            labels.additem(me.l_gw_ry)
            labels.additem(me.l_station_zf)
        end sub

  '得到label的起始相對于picture的位置
        public sub getlabelpositon()
            m_l_gw_ry_x = (me.l_gw_ry.location.x - me.picturebox1.location.x) * me.m_strecthx + me.picturebox1.location.x
            m_l_gw_ry_y = me.l_gw_ry.location.y * me.m_strecthy

            m_l_station_zf_x = (me.l_station_zf.location.x - me.picturebox1.location.x) * me.m_strecthx + me.picturebox1.location.x
            m_l_station_zf_y = me.l_station_zf.location.y * me.m_strecthy
        end sub
        '根據picture的位置重繪label
        public sub stretchlabel()
            if m_l_first = true then
                me.l_gw_ry.font = new system.drawing.font("宋體", 9.0!, system.drawing.fontstyle.regular, system.drawing.graphicsunit.point, ctype(134, byte))
                l_gw_ry.setbounds(me.m_l_gw_ry_x - m_driftx, me.m_l_gw_ry_y - m_drifty, l_gw_ry.width * me.m_strecthx, l_gw_ry.height * me.m_strecthy)

                me.l_station_zf.font = new system.drawing.font("宋體", 9.0!, system.drawing.fontstyle.regular, system.drawing.graphicsunit.point, ctype(134, byte))
                l_station_zf.setbounds(me.m_l_station_zf_x - m_driftx, me.m_l_station_zf_y - m_drifty, l_station_zf.width * me.m_strecthx, l_station_zf.height * me.m_strecthy)
            else
               
                if ((l_gw_ry.location.x - m_driftx) < me.picturebox1.location.x) or ((l_gw_ry.location.x - m_driftx + l_gw_ry.size.width) > (me.picturebox1.size.width)) then

                    l_gw_ry.visible = false
                else
                    l_gw_ry.visible = true
                end if

                if (l_station_zf.location.x - m_driftx) < me.picturebox1.location.x or (l_station_zf.location.x - m_driftx + l_station_zf.size.width) > (me.picturebox1.size.width) then
                    l_station_zf.visible = false
                else
                    l_station_zf.visible = true
                end if

                l_gw_ry.setbounds(l_gw_ry.location.x - m_driftx, l_gw_ry.location.y - m_drifty, l_gw_ry.width, l_gw_ry.height)
                l_station_zf.setbounds(l_station_zf.location.x - m_driftx, l_station_zf.location.y - m_drifty, l_station_zf.width, l_station_zf.height)

            end if
            m_l_first = false
        end sub
    end class

end namespace