VB6中模拟按钮的实现

朋友发来一个 VB6 的小要求：自行绘制按钮，并且按钮不能有句柄，不得用 Image 控件，需要支持单击事件，鼠标移动上去会变化。感觉像个考试题啊！

 

先贴代码：

VERSION 5.00Begin VB.Form Form1 Caption = "Form1" ClientHeight = 3090 ClientLeft = 60 ClientTop = 450 ClientWidth = 4680 LinkTopic = "Form1" ScaleHeight = 3090 ScaleWidth = 4680 StartUpPosition = 3 '窗口缺省 Begin VB.Image Image3 Height = 1215 Left = 1560 Top = 1680 Width = 2655 EndEndAttribute VB_Name = "Form1"Attribute VB_GlobalNameSpace = FalseAttribute VB_Creatable = FalseAttribute VB_PredeclaredId = TrueAttribute VB_Exposed = FalseDim pic1 As StdPicture, pic2 As StdPictureDim btnLeft As Single, btnTop As SingleDim btnRight As Single, btnBottom As SingleDim inButton As Boolean, last As BooleanPrivate Sub Form_Load() Set pic1 = LoadPicture(App.Path + "/111.bmp") Set pic2 = LoadPicture(App.Path + "/112.bmp") btnLeft = 150: btnTop = 150 ' 亮点在这里啊 btnRight = ScaleX(pic1.Width, vbHimetric, vbPixels) * 15 + btnLeft btnBottom = btnTop + ScaleY(pic1.Height, vbHimetric, vbPixels) * 15 inButton = False: last = inButton Image3.Picture = pic1 MsgBox Image3.Picture.Width & " x " & Image3.Picture.Height & vbNewLine & _ Image3.Width & " x " & Image3.Height End SubPrivate Function IsMouseInButton(X As Single, Y As Single) As Boolean IsMouseInButton = (X <= btnRight And X >= btnLeft) And (Y <= btnBottom And Y >= btnTop)End FunctionPrivate Sub Form_MouseMove(Button As Integer, Shift As Integer, X As Single, Y As Single) Debug.Print "x: " & X & " y: " & Y & " Button: " & Button inButton = IsMouseInButton(X, Y) If inButton <> last Then Me.Refresh Debug.Print "InButton: " & inButton & ", last: " & last End If last = inButtonEnd SubPrivate Sub Form_MouseUp(Button As Integer, Shift As Integer, X As Single, Y As Single) If inButton Then MsgBox ("button clicked.") End IfEnd SubPrivate Sub Form_Paint() If inButton Then PaintPicture pic2, btnLeft, btnTop Else PaintPicture pic1, btnLeft, btnTop End IfEnd Sub

思路就是 使用 PaintPicture 在窗体上作图，使用MouseMove事件判定鼠标是否在图片的位置上，如果是则绘制鼠标移动浮动后的图片，否则就绘制原始按钮图片。

在判断鼠标位置是否在图片位置的这块功能中发现一个问题，StdPicture.Width比图片的实际长度要大，不知道是什么原因造成的。使用必应搜索MS网站无结果，最后依靠伟大的google搜索外国网友的疑问找到解决方法，必须使用 ScaleX 和 ScaleY 函数计算图片在设备（此处是窗体）上的实际大小。

 

花了大约两个小时的时间，好在有一点收获。不错。