C # generics-use static member variables with caution

For the declaration of a generic class
which uses the type parameter's constructed type, such as list<t>, which is called an open constructed type (open constructed type)
A constructed type that does not use a type parameter, such as List<int>, is called a closed constructed type (closed constructed type).
It is particularly emphasized that static member variables are not shared between closed constructed types with different types of parameters.

As an example,

Using System;

public class List<t>
{
Public List (T t)
{
_value = t;
_closedcount++;
}

Public T Value
{
get {return _value;}
}

public int Closedcount
{
get {return _closedcount;}
}

public static int Staticcount
{
get {return _closedcount;}
}

Private T _value;
private static int _closedcount = 0;
}

public class Test
{
static void Main ()
{
List<double> List1 = new list<double> (3.14);
Console.WriteLine ("List1 Value: {0} \ t Closed Count: {1}", List1. Value, List1. Closedcount);

list<double> list2 = new list<double> (0.618);
Console.WriteLine ("List2 Value: {0} \ t Closed Count: {1}", List2. Value, List2. Closedcount);

list<string> list3 = new List<string> ("Divino");
Console.WriteLine ("List3 Value: {0} \ t Closed Count: {1}", List3. Value, List3. Closedcount);

Console.WriteLine ();

Console.WriteLine ("list<double> Count: {0}", List<double>. Staticcount);
Console.WriteLine ("list<string> Count: {0}", List<string>. Staticcount);
}
}

Output Result:
List1 value:3.14 Closed count:1
List2 value:0.618 Closed Count:2
List3 Value:divino Closed count:1

List<double> Count:2
List<string> count:1

which
List1 and List2 are list<double> they share static members _closedcount
List3 of type list<string> cannot be used _closedcount
We can also see the results from the last two lines of output
That is, static member variables are not shared between closed constructed types of different types of parameters.

C # generics-use static member variables with caution