我试图自动克隆一个对象,而不必实例化一个新对象并手动复制每个变量。
我记得当天(当我每天都做VB6时)我想出了一种使用PropertyBag克隆对象的方法,这非常酷。但是我丢失了代码,不记得怎么做了。
有人记得还是有其他方法?
答案 0 :(得分:4)
我过去使用的方法是将所有实例变量放在UDT上。只要您使UDT保持最新,您就可以使用单个方法/语句复制类的数据。
给出一个“Person”类,这是一个简单的例子:
Private Type tPerson
ID As Long
FirstName As String
LastName As String
End Type
Private m_Person As tPerson
Public Sub InitPerson(ID As Long, FirstName As String, LastName As String)
m_Person.ID = ID
m_Person.FirstName = FirstName
m_Person.LastName = LastName
End Sub
Friend Sub SetData(PersonData As tPerson)
m_Person = PersonData
End Sub
Public Function GetClone() As Person
Dim p As New Person
p.SetData m_Person
Set GetClone = p
End Function
Public Property Get FirstName() As String
FirstName = m_Person.FirstName
End Property
Private Type tPerson
ID As Long
FirstName As String
LastName As String
End Type
Private m_Person As tPerson
Public Sub InitPerson(ID As Long, FirstName As String, LastName As String)
m_Person.ID = ID
m_Person.FirstName = FirstName
m_Person.LastName = LastName
End Sub
Friend Sub SetData(PersonData As tPerson)
m_Person = PersonData
End Sub
Public Function GetClone() As Person
Dim p As New Person
p.SetData m_Person
Set GetClone = p
End Function
Public Property Get FirstName() As String
FirstName = m_Person.FirstName
End Property
尝试代码:
Dim p As New Person
p.InitPerson 1, "MyName", "MyLastName"
Dim p2 As Person
Set p2 = p.GetClone
MsgBox p2.FirstName
如果你在UDT中维护所有实例变量而不是单独声明它们,你可以使用简单的Clone方法,只需要很少的维护。
另一个优点是您可以将UDT放到文件句柄中,以便快速序列化到磁盘。
Dim p As New Person
p.InitPerson 1, "MyName", "MyLastName"
Dim p2 As Person
Set p2 = p.GetClone
MsgBox p2.FirstName
一个穷人的序列化解决方案真的: - )
答案 1 :(得分:4)
this您要找的是什么?文章在下面复制给后人。
您可以通过将数据放入PropertyBag对象,然后读取PropertyBags Contents属性来快速序列化数据。此属性实际上是一个Byte数组,它是PropertyBag对象中数据的序列表示形式。您可以将此字节数组用于多种用途,包括通过DCOM进行数据传输的有效方法:
Private Function PackData() As String
Dim pbTemp As PropertyBag
'Create a new PropertyBag object
Set pbTemp = New PropertyBag
With pbTemp
'Add your data to the PB giving each item a
'unique string key
Call .WriteProperty("FirstName", "John")
Call .WriteProperty("MiddleInitial", "J")
Call .WriteProperty("LastName", "Doe")
'Place the serialized data into a string
'variable.
Let PackData = .Contents
End With
Set pbTemp = Nothing
End Function
要检索序列化数据,只需创建一个新的PropertyBag对象并将序列化字符串设置为其Contents属性。将字符串转换为字节数组,然后将其分配给Contents属性:
Private Sub UnPackData(sData As String)
Dim pbTemp As PropertyBag
Dim arData() As Byte
'Convert the string representation of the data to
'a Byte array
Let arData() = sData
'Create a new PropertyBag object
Set pbTemp = New PropertyBag
With pbTemp
'Load the PropertyBag with data
Let .Contents = arData()
'Retrieve your data using the unique key
Let m_sFirstName = .ReadProperty("FirstName")
Let m_sMiddleInitial = _
.ReadProperty("MiddleInitial")
Let m_sLastName = .ReadProperty("LastName")
End With
Set pbTemp = Nothing
End Sub
Mike Kurtz,McKees Rocks,Pa。
答案 2 :(得分:1)
答案 3 :(得分:1)
我的应用程序框架中的每个对象都有一个Read和Store方法。我所做的是传递一个写入bytearray并存储字节数组的流。虽然这并没有消除必须处理每个属性,你只需要处理一次阅读和一次处理。
另一种方法是使用像Darrel Miller这样的财产袋,但你仍然必须单独处理每个房产。如果您已经阅读并存储,那么我的建议应该节省一些时间。