通过TreeView.Nodes分配TreeNodeCollection [英] Assign TreeNodeCollection through TreeView.Nodes

问题描述

我已经声明了TreeNodeCollection

I have declared a TreeNodeCollection

public TreeNodeCollection NewTreeCollection ;
NewTreeCollection = MyTreeview.Nodes;

现在在

Now in

tabIndexChanged(object sender, EventArgs e) //event
{
//I am storing the NewTreeCollection into a global class object
InterfaceData.tnCollectionNodes = this.NewTreeCollection //InterfaceData is globalclass object

for (int i= 0; i< InterfaceData.Items.Count<object>(); i++)
{
if ((InterfaceData.Items[i])).PCNames.Equals(tabControl.SelectedTab.Text))
     {
       if (InterfaceData.Items[i].tnCollectionNodes.Count > 0)
           {
             this.MyTreeview.Nodes.Clear();
             this.MyTreeview.Nodes.Add(InterfaceData.Items[i].tnCollectionNodes[0]);
                                    break;
           }
     }
else
     {
       this.MyTreeview.Nodes.Clear();
     }
}

问题出现了，当我做

Here the problem comes, when I am doing

this.MyTreeview.Nodes.Clear(); 

NewTreeCollection正在成为null以及全局类对象

the NewTreeCollection is becomming null as well as the global class object

InterfaceDetails.Items[i] is also becomming null.

你可以帮助我如何将数据存储在全局类中，以便在

Can u please help me how i can store the data in the global class so that the global class does not become null after

this.MyTreeview.Nodes.Clear();

推荐答案

你需要制作一个< a href =http://msdn.microsoft.com/en-us/library/system.windows.forms.treenodecollection.copyto.aspx> copy [ ^ ]。请记住，当您使用以下内容初始化参考时：

You need to make a copy[^] of the original before clearing it. Remember, when you initialise the reference with:

NewTreeCollection = MyTreeview.Nodes;

NewTreeCollection 只是原始的引用（指针），而不是它的副本。

that NewTreeCollection is merely a reference (pointer) to the original, not a copy of it.

你是全局类对象只是一个引用您的本地对象。无论您对全局对象执行何种操作，都可以在本地对象上执行（反之亦然）。将您的全局对象视为指向本地对象的指针，而不是对象的副本。



为了做你想做的事，你需要创建一个深度复制树节点集合的方法。 在此处查看解决方案 [ ^ ]。还有其他方法可以使用序列化和内存流，但我认为你应该选择简单的东西。



BTW，C＃（.NET）中的所有对象都以相同的方式运行，你传递的是对象引用，而不是整个新对象。

You're "global" class object is just a reference to your local object. Whatever operations you perform on your global object, also get performed on your local object (and vice-versa). Think of your global object as a pointer to your local object, not a copy of the object.

In order to do what you are wanting, you need to create a method to "deep copy" the tree node collection. Look at the solution here[^]. There are other ways to do it, using serialization and memory streams, but I think you should opt for something simple.

BTW, all objects in C# (.NET) act the same way, you are passing around object references, not entire new objects.

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