c# - 为什么我会收到此编译错误？

Question

为什么我不能使用下面的选项 #1。选项 2 工作正常

class Program
    {
        static void Main()
        {
             //Option 1  
            //Error 1   The best overloaded method match for 'ConsoleApplication2.Program.SomeMethod(System.Collections.Generic.List<string>)' has some invalid argument
            //Error 2   Argument 1: cannot convert from 'void' to 'System.Collections.Generic.List<string>'
            SomeMethod(new List<string>().Add("This give compilation Error"));

            //Option 2 
            List<string> MyMessages = new List<string>();
            MyMessages.Add("This compiles fine");
            SomeMethod(MyMessages);
        }

        static void SomeMethod(List<string> Messages)
        {
            foreach (string Message in Messages)
                Console.WriteLine(Message);
        }
    } 

Answer 1

List<T>.Add 返回 void .您的代码失败的方式与此失败的方式相同:

List<string> list = new List<string>().Add("This wouldn't work");

但是，C# 3 使用集合初始化器来拯救:

SomeMethod(new List<string> { "Woot!" });