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1、添加一个“label控件”命名为label
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2、添加一个“timer控件”命名为timer1
3、设置“timer1”的“Interval属性”为1000
使用到的代码：
Dim Hour As Integer '小时
Dim Min As Integer '分钟
Dim Sec As Integer '秒
Private Sub Form_Load()
Hour = 0
Min = 0
Sec = 0
Label1.Caption = "00 : 00 : 00"
End Sub
Private Sub Timer1_Timer()
Dim strHour As String
Dim strMin As String
Dim strSec As String
Sec = Sec + 1
If Sec = 60 Then
Sec = 0
Min = Min + 1
If Min = 60 Then
Min = 0
Hour = Hour + 1
If Hour = 24 Then
Hour = 0
End If
End If
End If
If Hour 10 Then
strHour = "0" Hour
Else
strHour = Hour
End If
If Min 10 Then
strMin = "0" Min
Else
strMin = Min
End If
If Sec 10 Then
strSec = "0" Sec
Else
strSec = Sec
End If
Label1.Caption = strHour " : " strMin " : " strSec
End Sub
就
是
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个
了
！
Hand类的代码：
Public MustInherit Class Hand
Protected gp As GraphicsPath = New GraphicsPath()
Protected gpBase As GraphicsPath = Nothing
Protected midX As Integer = 150 ‘默认的窗体
Protected midY As Integer = 150 ‘中心位置
‘构造器，得到窗体中心位置
Public Sub New(ByVal theForm As Form1)
midX = (theForm.ClientRectangle.Left + theForm.ClientRectangle.Right) / 2
midY = (theForm.ClientRectangle.Top + theForm.ClientRectangle.Bottom) / 2
End Sub
MustOverride Sub Transform(ByVal d As DateTime)
‘绘制指针路径
Overridable Sub Draw(ByVal g As Graphics)
Dim aPen As Pen = New Pen(Brushes.Black, 4F)
g.DrawPath(aPen, gp)
g.FillPath(Brushes.Black, gp)
aPen.Dispose()
End Sub
‘使用矩阵实现路径（gp）的旋转
Public Sub Rotate(ByVal angle As Double)
gp = CType(gpBase.Clone(), GraphicsPath)
Dim mTransform As Matrix = New Matrix()
mTransform.RotateAt(CType(angle,Single),NewPointF(midX,midY))
gp.Transform(mTransform)
End Sub
End Class
为了节省篇幅，上面的代码省略了引入命名空间的语句。
下面是分针（MinuteHand）类的定义：
Public Class MinuteHand
Inherits Hand
‘构造器，生成绘制分针的路径（gp）
Public Sub New(ByVal myForm As Form1)
MyBase.New(myForm)
gp.AddLine(midX, midY, midX, 45)
gp.AddLine(midX, 45, midX - 3, 50)
gp.AddLine(midX - 3, 50, midX + 3, 50)
gp.AddLine(midX + 3, 50, midX, 45)
gpBase = CType(gp.Clone(), GraphicsPath)
End Sub
‘Transform方法取得系统当前时间，并旋转时钟指针。
Public Overrides Sub Transform(ByVal d As DateTime)
Dim minuteTime As Double = (CDbl(d.Minute) + CDbl(d.Second / 60))
Dim angle As Double = (CDbl(minuteTime) / 60) * 360
Rotate(angle)
End Sub
End Class
对所有的指针旋转的方法都是相同的，因此在基类中实现。由于时针和秒针的实现与分针相似，所不同者，只在于构造器中绘制的指针路径不同和Transform方法中转动的角度不同，在这里就不在赘述了。
另外还需要提一下的是画时钟表面的代码，时钟表面用ClockFace类来实现。这个类首先画一个圆代表时钟，然后画上米老鼠的图案，最后在相应的位置画上数字1～12代表12个小时。
Public Sub Draw(ByVal g As Graphics)
DrawClockFace(g)
DrawImage(g)
DrawNumbers(g)
DrawPin(g)
End Sub
下面是ClockFace类的属性：
Private ClockRectangle As Rectangle
Private ClockFont As Font = New Font("Arial", 12)
Private midPoint As Point
Private ClockImage As Bitmap
Private Const IMAGEX As Integer = 50
Private Const IMAGEY As Integer = 50
DrawClockFace方法用来画时钟表面：
Private Sub DrawClockFace(ByVal g As Graphics)
g.FillEllipse(Brushes.White, ClockRectangle.Left + 10, ClockRectangle.Top + 10, ClockRectangle.Width - 20, ClockRectangle.Height - 20)
g.DrawEllipse(Pens.Black, ClockRectangle.Left + 10, ClockRectangle.Top + 10, ClockRectangle.Width - 20, ClockRectangle.Height - 20)
End Sub
然后用Graphics对象的DrawImage方法画出米老鼠的图片：
Private Sub DrawImage(ByVal g As Graphics)
Dim nWidth As Integer = ClockImage.Width
Dim nHeight As Integer = ClockImage.Height
Dim destRect As Rectangle = New Rectangle(midPoint.X - IMAGEX / 2, midPoint.Y - IMAGEY / 2, IMAGEX, IMAGEY)
g.DrawImage(ClockImage, destRect)
End Sub
数字在时钟上的位置是用sin和cos函数计算的：
Private Sub DrawNumbers(ByVal g As Graphics)
Dim count As Integer = 1
Dim a As Double
For a = 0 To 2 * Math.PI Step 2 * Math.PI / 12
Dim x As Double = (ClockRectangle.Width - 70) / 2 * Math.Cos(a - Math.PI / 3) + (ClockRectangle.Width - 70) / 2 + 25
Dim y As Double = (ClockRectangle.Width - 70) / 2 * Math.Sin(a - Math.PI / 3) + (ClockRectangle.Width - 70) / 2 + 20
g.DrawString(Convert.ToString(count), ClockFont, Brushes.Black, CType(x, Single), CType(y, Single), New StringFormat())
count += 1
Next
End Sub
最后是窗体文件（Form1.vb）:
Public Class Form1
Inherits System.Windows.Forms.Form
Private MyMinuteHand As MinuteHand
Private MyHourHand As HourHand
Private MySecondHand As SecondHand
Private TheClockFace As ClockFace
Private FirstTick As Boolean = False
‘在窗体的OnPaint事件中取得Graphics对象
Protected Overrides Sub OnPaint(ByVal e As System.Windows.Forms.PaintEventArgs)
If (FirstTick = False) Then Exit Sub
Dim g As Graphics = e.Graphics
TheClockFace.Draw(g)
MyHourHand.Draw(g)
MyMinuteHand.Draw(g)
MySecondHand.Draw(g)
TheClockFace.DrawPin(g)
End Sub
‘计时器事件
Private Sub Timer1_Tick(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Timer1.Tick
MySecondHand.Transform(DateTime.Now)
MyHourHand.Transform(DateTime.Now)
MyMinuteHand.Transform(DateTime.Now)
FirstTick = True
Invalidate()
Private Sub Form_Load()
Me.Caption = "数字时钟"
Timer1.Interval = 1000
Timer1.Enabled = True
End Sub
Private Sub Timer1_Timer()
Label1.Caption = Format(Now, "yyyy年m月d日")
Label2.Caption = Format(Now, "hh时nn分ss秒")
End Sub
