如何更改某些包含引用类型对象的复制列表而不更改原始列表

Question

I Have List<PropertyDetails> OriginalList which I clone it to another list by : List<PropretyDetails> CopiedList = OriginalList.ToList();

Now I pass the CopiedList to some method that alters it.

Myproblem is the alterations are reflected to the OriginalList

Answer 1

A reference type is really a pointer to an object. And because PropertyDetails is also a reference type, copying the list just gives you a new list of pointers that point to the original objects. As Habbib pointed out, you'll have to create copies of the objects in the list, and build a new list that contains these copies.

Answer 2

If you are doing something like this: CopiedList[0] = OriginalList[0] and the objects are reference types, CopiedList[0] will be pointing to the same address in memory than OriginalList[0]. Thus, when you change something for CopiedList[0] you will be editing the same object in memory in OriginalList. When you are copying the objects to the CopiedList you will need to create a new instance of that object with the same values of the OriginalList. You can take a look at ICloneable Interface which is the standard way of doing this. Also there are other questions related to this, like for example this one: Deep cloning objects

Answer 3

I think what you want to do is clone your list to make some changes without having the original one modified, right?

Check @ajm answers in here: https://stackoverflow.com/a/222640/1435499

You can actually create a extension method to clone the list :), it shouldn't be hard.