引用类型的行为就像在VB.NET值类型 [英] Reference types behaves like value type in VB.NET

问题描述

尽管串是引用类型，在VB.NET中，我们只有使用引用类型的，如果我们传递一个参数作为ByRef的效果。因此，与C＃甚至引用类型在VB.NET行为就像默认值类型。为什么会出现这种差异？

Even though "String" is a reference type, in VB.NET, we only get the effect of using of a reference type if we pass a parameter as ByRef. So, unlike C# even reference types in VB.NET behaves like value type by default. Why is there this kind of difference?

推荐答案

如果你想了解使用字符串作为一个例子，那么你会混淆自己大的引用类型和价值类型及其在VB.NET和C＃.NET差异时间。

If you are trying to understand reference types and value types and their differences in VB.NET and C#.NET using string as an example then you will confuse yourself big time.

正如大卫所说，字符串是引用类型，但他们是特殊的，那就是不可变的。这意味着，一旦你在参考地址创建一个字符串，则不能对其进行修改。如果你尝试这样做，那么.NET将保存修改后的串上不同的地址，并开始指向新的地址。旧的地址将作为垃圾收集一段时间。

Just as David mentioned, strings are reference types, but they are special, that is, immutable. Which means that once you have created a string on a reference address you cannot modify them. If you try to do that then .NET will store your modified string on a different address and start pointing to the new address. The old address will get garbage collected over a period of time.

例如

string str = "new string"; //One address space
str = "modified" + str; //Different address and not same address as above

此外，当你传递一个字符串参考的方法和修改字符串中的方法，实际上它只是指向一个不同的参考，但它让你感觉，实际参考的更新。

Moreover, when you are passing a string by reference to a method and modifying the string in the method, it is actually just pointing to a different reference, but it makes you feel that the actual reference is updated.

我希望这阐明你的问题有点。

I hope this clarifies your question a little.

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