复制类属性 [英] Copy Class Properties

问题描述

如何使用byval方法将类的所有属性复制到另一个类？

Hi,

How to copy all properties of a class to another class using byval method?

Dim Xglobal as new NameClass
Dim Xlocal as new NameClass


XLocal = XGlobal

i使用上面的方法，它运作良好，但是当我更改xglobal类中的属性值，它也会自动更改xlocal属性的值。 （我想分配像byval methoid这样的值。）

i use the above method, it works good, but when i change a property value in xglobal class it automatically changes the values of xlocal properties also. (I want to assign the values like byval methoid).

推荐答案

Quote：

XLocal = XGlobal

XLocal = XGlobal

上面的行只是将引用 XGlobal 分配给 XLocal ：它们是两个变量持有对同一个对象的引用。



您应该使用 MemberwiseClone [ ^ ]方法。但请，请，请确保理解浅层副本（以及深层副本），即：r 仔细阅读文档（以及代码示例）。

The above line simply assigns the reference XGlobal to XLocal: they are then two variables holding the reference to the same object.

You should instead use MemberwiseClone[^] method. However, please, please, please, make sure to understand what a shallow copy is (and what a deep copy is), that is: read carefully the documentation (and the code example).

您需要提供 Copy（）方法;），它返回具有默认属性的新类。

：

You need to provide Copy() method ;) which returns new class with default properties.

in pseudo-code:

Class NameClass

    'declare and implement many properties and methods

    'provide Copy method
    Public Function Copy() As NameClass
        Dim newClass As NameClass
        newClass.Property1 = Me.Property1
        newClass.Property2 = Me.Property2
        Return New newClass
    End Function

    'another members of class

End Class

用法：

Usage:

Dim Xglobal as new NameClass
With Xglobal
   'here set properties
End With

Dim Xlocal as new NameClass = Xglobal.Copy() 'simple?

成员克隆

在NameClass中创建一个新的公共函数克隆

Member-wise clone
create a new public function clone in your NameClass

Public class NameClass
   Public Function clone() As NameClass
        Dim ObjOriginal = Me
        Dim ObjCopied As New NameClass
        'set desired property values from original object to the object you want to copy
        ObjCopied.Property1 = ObjOriginal.Property1
        Return ObjCopied 
    End Function
'other property & methods...
End Class

现在......而不是你的代码......

Now... instead of your code...

Dim Xglobal as new NameClass
Dim Xlocal as new NameClass
XLocal = XGlobal.Clone()

快乐编码！

：）

Happy Coding!
:)

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