标签： 培训

‘一、建立子类 CAddress.cls
Private m_Street As String
Private m_City As String

Public Property Get Street() As String
Street = m_Street
End Property

Public Property Let Street(ByVal sStreet As String)
m_Street = sStreet
End Property

Public Property Get City() As String
City = m_City
End Property

Public Property Let City(ByVal sCity As String)
m_City = sCity
End Property

‘ 二、建立父类 CPerson.cls
Private m_Address As CAddress ‘ 声明 CAddress 类型的私有变量

‘ 自动初始化 CAddress 实例
Private Sub Class_Initialize()
Set m_Address = New CAddress
End Sub

‘ 清理资源
Private Sub Class_Terminate()
Set m_Address = Nothing
End Sub

‘ 通过 Property Get 公开 CAddress 实例
Public Property Get Address() As CAddress
Set Address = m_Address
End Property

‘ 可选：允许外部设置 CAddress 实例
Public Property Set Address(ByVal objAddress As CAddress)
Set m_Address = objAddress
End Property

‘ 三、在窗体或模块中使用：
Dim person As CPerson
Set person = New CPerson

‘ 设置地址属性
With person.Address
.Street = “123 Main St”
.City = “New York”
End With

‘ 读取地址属性
MsgBox “地址：” & person.Address.Street & “, ” & person.Address.City

‘四、注意事项

Set person.Address = New CAddress ‘ 正确
person.Address = New CAddress ‘ 错误（缺少 Set）

‘ 一、类模块代码

‘ 类名: clsWire
‘ 包含8个参数、2个方法、1个事件

Option Explicit

‘ —————————-
‘ 1. 定义私有变量（8个参数）
‘ —————————-
Private pMaterial As String ‘ 材料
Private pLength As Double ‘ 长度
Private pDiameter As Double ‘ 直径
Private pVoltage As Double ‘ 电压
Private pCurrent As Double ‘ 电流
Private pResistance As Double ‘ 电阻
Private pTemperature As Double ‘ 温度
Private pIsInsulated As Boolean ‘ 是否有绝缘层

‘ —————————-
‘ 2. 定义事件
‘ —————————-
Event StatusChanged(ByVal Message As String)

‘ —————————-
‘ 类初始化（设置默认值）
‘ —————————-
Private Sub Class_Initialize()
pMaterial = “Copper” ‘ 默认材料为铜
pLength = 0
pDiameter = 0
pVoltage = 0
pCurrent = 0
pResistance = 0
pTemperature = 25 ‘ 默认温度25°C
pIsInsulated = False
End Sub

‘ —————————-
‘ 属性定义（8个参数）
‘ —————————-
Public Property Get Material() As String
Material = pMaterial
End Property
Public Property Let Material(ByVal Value As String)
pMaterial = Value
End Property

Public Property Get Length() As Double
Length = pLength
End Property
Public Property Let Length(ByVal Value As Double)
pLength = Value
End Property

Public Property Get Diameter() As Double
Diameter = pDiameter
End Property
Public Property Let Diameter(ByVal Value As Double)
pDiameter = Value
End Property

Public Property Get Voltage() As Double
Voltage = pVoltage
End Property
Public Property Let Voltage(ByVal Value As Double)
pVoltage = Value
End Property

Public Property Get Current() As Double
Current = pCurrent
End Property
Public Property Let Current(ByVal Value As Double)
pCurrent = Value
End Property

Public Property Get Resistance() As Double
Resistance = pResistance
End Property
Public Property Let Resistance(ByVal Value As Double)
pResistance = Value
End Property

Public Property Get Temperature() As Double
Temperature = pTemperature
End Property
Public Property Let Temperature(ByVal Value As Double)
pTemperature = Value
End Property

Public Property Get IsInsulated() As Boolean
IsInsulated = pIsInsulated
End Property
Public Property Let IsInsulated(ByVal Value As Boolean)
pIsInsulated = Value
End Property

‘ —————————-
‘ 方法1：计算功率
‘ —————————-
Public Function CalculatePower() As Double
CalculatePower = pVoltage * pCurrent ‘ P = V * I
RaiseEvent StatusChanged(“功率计算完成: ” & CalculatePower & “W”)
End Function

‘ —————————-
‘ 方法2：检查安全性
‘ —————————-
Public Sub CheckSafety()
Dim msg As String
If pTemperature > 80 Then
msg = “警告：温度过高（” & pTemperature & “°C）！”
ElseIf pCurrent > 10 Then
msg = “警告：电流超过安全阈值！”
Else
msg = “系统状态正常”
End If
RaiseEvent StatusChanged(msg) ‘ 触发事件
End Sub

‘ 二、调用

‘ 在窗体代码中：
Dim WithEvents myWire As clsWire ‘ 必须使用 WithEvents 捕获事件

Private Sub Form_Load()
Set myWire = New clsWire
myWire.Voltage = 220
myWire.Current = 5
myWire.Temperature = 75

‘ 调用方法
Debug.Print “功率：” & myWire.CalculatePower()
myWire.CheckSafety

End Sub

‘ 处理事件
Private Sub myWire_StatusChanged(ByVal Message As String)
MsgBox Message, vbInformation, “导线状态”
End Sub