2019-2-24-2019-2-24-C#中的弃元

var dict = new ConcurrentDictionary<int,int>
dict[]=;
var result = dict.TryRemove(, out var value);
Console.WriteLine(result);

var dict = new ConcurrentDictionary<int,int>();
dict[1]=1;
var result = dict.TryRemove(1,out _);
Console.WriteLine(result);

var (year,_,_) = GetDate();

private (string,string,string) GetDate()
{
	//...
    return (year,month,day);
}

Foo("10");

void Foo(object item)
{
	switch (item)
	{
	     case int val:
             Console.WriteLine(val);
	         break;
	     case string _:
	         Console.WriteLine("Error");
	         break;
	}
}