为什么我可以在C＃中执行此操作？（带有（）的公共类

Question

In C# why am I able to compile and run a program with the following code

public class HammingTFTP()
{
     //class variables here
     public HammingTFTP(string mode, string host, string fileName)
           :this()
     {
        //code here
     }
}

I am coding on a mac and running mono 3.6.0. I understand there should be no () after the class declaration and i should remove :this(). Just wondering why this compiles and runs in the first place. Could it be a bug with the given version of mono?

Answer 1

This doesn't compile with the .NET compiler, but it does with the Roslyn compiler. Demo: https://dotnetfiddle.net/HkngI3

This is a C# 6.0 feature called "Primary Constructors". See The New and Improved C# 6.0

It allows you to declare a primary constructor for the class alongside its declaration, such as:

public class MyClass(string name)
{
    public string Name {get; } = name;  
}

Answer 2

Mono 3.6.0 already supports some of the features that will come in C# 6.0, as stated here .

In your case this is namely primary constructors. See this language preview for more details.

Without using primary constructors, your code would translate as follows:

public class HammingTFTP
{
    // generated via primary constructor
    public HammingTFTP()
    {
    }

    //class variables here
    public HammingTFTP(string mode, string host, string fileName)
       :this()
    {
       //code here
    }
}