C＃4.0，可选参数和参数不起作用

Question

如何创建一个具有可选参数和参数在一起的方法？

static void Main(string[] args)
{

    TestOptional("A",C: "D", "E");//this will not build
    TestOptional("A",C: "D"); //this does work , but i can only set 1 param
    Console.ReadLine();
}

public static void TestOptional(string A, int B = 0, params string[] C)
{
    Console.WriteLine(A);
    Console.WriteLine(B);
    Console.WriteLine(C.Count());
}   

Answer 1

您现在只有您的选择是超载testOptional（就像您在C＃4之前必须执行的那样）。不是首选，但它在使用时清理了代码。

public static void TestOptional(string A, params string[] C)
{
    TestOptional(A, 0, C);
}

public static void TestOptional(string A, int B, params string[] C)
{
    Console.WriteLine(A);
    Console.WriteLine(B);
    Console.WriteLine(C.Count());
}

Answer 2

TestOptional("A", C: new []{ "D", "E"});

Answer 3

    static void Main(string[] args) {

        TestOptional("A");
        TestOptional("A", 1);
        TestOptional("A", 2, "C1", "C2", "C3"); 

        TestOptional("A", B:2); 
        TestOptional("A", C: new [] {"C1", "C2", "C3"}); 

        Console.ReadLine();
    }

    public static void TestOptional(string A, int B = 0, params string[] C) {
        Console.WriteLine("A: " + A);
        Console.WriteLine("B: " + B);
        Console.WriteLine("C: " + C.Length);
        Console.WriteLine();
    }

Answer 4

public static void TestOptional(string A, params string[] C)
{
    TestOptional(A, C: C);
}


public static void TestOptional(string A, int B =0, params string[] C)
{
    Console.WriteLine("A: " + A);
    Console.WriteLine("B: " + B);
    Console.WriteLine("C: " + C.Length);
    Console.WriteLine();
}