一个用VB编写ActiveX自定义控件的例子——进度条控

设计方法：
   
   1.在UserControl中添加一个Label控件Label1，将它设为平面，用来做外框。添加两个PictureBox控件PictureBox1做为进度指示，PictureBox2控件做为控件背景。
   
   
   2.加入以下代码
   
   Option Explicit
   
   ''定义私有变量用于存储属性值
   Private mvarMax As Long
   Private mvarMin As Long
   Private mvarValue As Long
   
   Private Rate As String
   
   Private Sub UserControl_Initialize()
   ''初始化
   Picture2.BackColor = vbBlue
   End Sub
   
   Public Property Get BackColor() As OLE_COLOR
   ''读取BackColor属性
   BackColor = Picture1.BackColor
   End Property
   
   Public Property Let BackColor(ByVal vNewValue As OLE_COLOR)
   ''设置BackColor属性
   Picture1.BackColor = vNewValue
   End Property
   
   Private Sub UserControl_InitProperties()
   ''初始化属性
   Max = 100
   Min = 0
   Value = 0
   End Sub
   
   Private Sub UserControl_ReadProperties(PropBag As PropertyBag)
   ''读取从属性窗体中设置的属性值
   mvarMax = PropBag.ReadProperty("Max", 100)
   mvarMin = PropBag.ReadProperty("Min", 0)
   ''Value属性值这里未提供，主要是模仿VB自带的进度条控件
   ''mvarValue = PropBag.ReadProperty("Value", 0)
   End Sub
   
   Private Sub UserControl_WriteProperties(PropBag As PropertyBag)
   ''保存从属性窗体中设置的属性值
   PropBag.WriteProperty "Max", mvarMax, 100
   PropBag.WriteProperty "Min", mvarMin, 0
   ''PropBag.WriteProperty "Value", mvarValue, 0
   End Sub
   
   Private Sub UserControl_Resize()
   ''Resize事件
   Label1.Move 0, 0, UserControl.Width / Screen.TwipsPerPixelX, UserControl.Height / Screen.TwipsPerPixelY
   Picture1.Move 1, 1, UserControl.Width / Screen.TwipsPerPixelX - 2, UserControl.Height / Screen.TwipsPerPixelY - 2
   Picture2.Move 1, 1, 1, UserControl.Height / Screen.TwipsPerPixelY - 2
   End Sub
   
   Public Property Get Max() As Long
   ''读取Max属性
   Max = mvarMax
   End Property
   
   Public Property Let Max(ByVal vNewValue As Long)
   ''设置Max属性
   mvarMax = vNewValue
   If vNewValue < Min Then Err.Raise "1001", , "Max必须大于Min"
   End Property
   
   Public Property Get Min() As Long
   ''读取Min属性
   Min = mvarMin
   End Property
   
   Public Property Let Min(ByVal vNewValue As Long)
   ''设置Min属性
   If vNewValue > Max Then Err.Raise "1000", , "Min必须小于Max"
   mvarMin = vNewValue
   End Property
   
   Public Property Get Value() As Long
   ''读取Value属性
   Value = mvarValue
   End Property
   
   Public Property Let Value(ByVal vNewValue As Long)
   ''设置Value属性
   ''原理就是在两个PictureBox中以不同颜色打印百分比进度
   Dim DX As Long, DY As Long
   
   If vNewValue > Max Then Err.Raise "1002", , "Value不能大于Max"
   mvarValue = vNewValue
   
   Picture2.Width = Value / (Max - Min) * (UserControl.Width / Screen.TwipsPerPixelX - 2)
   Rate = Int(Value / (Max - Min) * 100) & "%"
   DX = (Picture1.Width - Picture1.TextWidth(Rate)) / 2
   DY = (Picture1.Height - Picture1.TextHeight(Rate)) / 2
   Picture1.ForeColor = vbBlack
   Picture2.ForeColor = vbWhite
   If DX < Picture2.Width Then
   Picture2.Cls
   Picture2.CurrentX = DX
   Picture2.CurrentY = DY
   Picture2.Print Rate
   Else
   Picture1.Cls
   Picture1.CurrentX = DX
   Picture1.CurrentY = DY
   Picture1.Print Rate
   End If
   End Property
   
   3.新建另一个测试工程，加入一个自己的进度条控件和一个系统的进度条控件，加入以下代码：
   
   Option Explicit
   
   Private Sub Command1_Click()
   Unload Me
   End Sub
   
   Private Sub Timer1_Timer()
   myProgressBar1.Value = myProgressBar1.Value + 2
   ProgressBar1.Value = ProgressBar1.Value + 2
   If myProgressBar1.Value = myProgressBar1.Max Then Timer1.Enabled = False
   End Sub
   
   
   OK.运行看看效果吧。