C# 计算类的实例
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Count instances of the class
提问by Tomas
Possible Duplicate:
how can i find out how many objects are created of a class in C#
Is it possible to get number of instances which is active(created and not yet destroyed) for selected class?
是否可以获得所选类的活动（已创建但尚未销毁）的实例数量？
For example:
例如：
public class MyClass { }
...
var c1 = new MyClass();
var c2 = new MyClass();
count = GetActiveInstances(typeof(MyClass))
Should return 2. If GC destroy any of these classes then 1 or 0.
应该返回 2。如果 GC 销毁了这些类中的任何一个，则返回 1 或 0。
采纳答案by Dor Cohen
You can holds global static counter in your program.
This is a simple thread safe solution:
您可以在程序中保存全局静态计数器。
这是一个简单的线程安全解决方案：
class MyClass
{
static int counter = 0;
public MyClass()
{
Interlocked.Increment(ref counter);
}
~MyClass()
{
Interlocked.Decrement(ref counter);
}
}
also take a look at the following similar question - Count number of objects of class type within class method
也看看下面的类似问题 -在类方法中计算类类型的对象数
回答by Jon
Only if you implement a counting mechanism inside the constructor (increment) and finalizer (decrement). But even that will not account for instances which are really inactive (noone has any reference to them) but have not been collected yet.
仅当您在构造函数（增量）和终结器（减量）中实现计数机制时。但即使这样也不会考虑那些真正不活动（没有人提到它们）但尚未收集的实例。
Moreover, adding a finalizer to a class -- no matter how trivial -- will adversely affect performance, which is an argument against doing so.
此外，向类添加终结器——无论多么微不足道——都会对性能产生不利影响，这是反对这样做的论据。
回答by Esben Skov Pedersen
public class MyClass
{
private static int count;
private static object _lock = new object();
public MyClass()
{
lock(_lock)
{
count++;
}
}
private ~MyClass()
{
lock(_lock)
{
count--;
}
}
}
回答by Can Poyrazo?lu
I don't know of a built in mechanism, but you can always incrase a private static variable in constructor.
我不知道内置机制，但是您始终可以在构造函数中增加私有静态变量。
public class MyClass
{
private static int instances = 0;
public MyClass() => instances++;
~MyClass() => instances--;
}
Haven't tried but should work.
没试过，但应该可以。
回答by SMK
You can try it by making a static variable for count in class and increment it in constructorand decrement in destructor.May this helps you.
您可以通过在类中创建一个用于计数的静态变量来尝试它，constructor并在destructor.
回答by Adil Mammadov
Try this one:
试试这个：
public class MyClass
{
public static int activeCount = 0;
public MyClass() => activeCount++;
~MyClass() => activeCount--;
}
//In the main
var testClass1 = new MyClass();
var testClass2 = new MyClass();
Console.WriteLine(MyClass.activeCount);
回答by Pranay Rana
Such thing is not possible but you can do something like
这种事情是不可能的，但你可以做类似的事情
Note :ClassInstancecan be also int value just to maintain count.
注意：ClassInstance也可以是 int 值只是为了保持计数。
public class MyType
{
public static List<MyType> ClassInstance = new List<MyType>();
public MyType() => ClassInstance.Add(this);
public RemoveClass(MyType t)
{
ClassInstance.Remove(t);
t = null;
}
public int ActiveCount => ClassInstance.Count;
}
回答by Gyan Chandra Srivastava
public class MyClass
{
public static int countinstance =0;
MyClass(){ countinstance ++;}
~ MyClass() {countinstance --; }
}
simple and easy get instance active by countinstance
简单轻松地通过计数实例激活实例
回答by Habib Zare
this :
这个 ：
public class MyClass
{
private static int instances = 0;
public MyClass()
{
instances++;
}
~MyClass()
{
instances--;
}
public static int GetActiveInstances()
{
return instances;
}
}
use :
用 ：
MyClass c1 = new MyClass();
MyClass c2 = new MyClass();
int count = MyClass.GetActiveInstances();
