c# Variable parameters params Introduction to

As a netUp Lord , In today's b The station is here java A video of , Introduction of variable parameters , So today I'd like to introduce to you c# Variable parameters in params Introduction to the use of ,

Let's first look at the official explanation : Use params Keyword can specify a variable number of parameters params. The parameter type must be a one-dimensional array . In the method declaration params No other parameters are allowed after the keyword , And only one is allowed in a method declaration params keyword . If params The declaration type of the parameter is not a one-dimensional array , A compiler error occurs params. Use params When a method is called with a parameter , You can pass in ：

• Comma separated list of parameters of array element type .

• An array of parameters of the specified type .

• No parameter . If no parameters are sent , be params The length of the list is zero .

Example

static void Main(string[] args)
  {
     string[] lst = new string[] { " Zhang San ", " Li Si ", " Wang Wu " };
     AddName(lst);
     AddName(" Zhang San "," Li Si "," Wang Wu ");
  }


 static void AddName(params string[] args)
  {
    string allName= string.Join(",", args);
  }

Variable parameters are used as above , When we define functions, we use keywords for arrays params, The array becomes a variable parameter , When calling, the data we pass in will form an array , When called, we can pass in no matter how many elements .

I understand the application scenarios of variable parameters , Variable parameters ( Array ) Not only can arrays be passed in , It can also be passed in the form of direct assignment of formal parameters when calling , It will still be treated as an array in the method , This is the advanced nature of variable parameters. .

Personally, I think it's just convenient before calling the method , Reduce the process of array instantiation , because up The main has hardly used variable parameters in its work , My understanding may be limited, and my friends who know can tell me more abundant usage scenarios , That's the end of today's presentation !