How to pass string array to asp.net mvc action method or Api

Question

I am trying to pass strings array to my mvc action but I am getting Null value.  

 

This is my javascript/Jquery 

 

var array = ["Good Morning", "Good Afternoon", "Good Evening"]

var postData= { imageList: array };

$('button').on('click', function () {

$.ajax({

url: "/Home/Greetings",

type: 'POST',

data: postData,

dataType: "json",

traditional: true,

success: function (data) {

array = [];

},

error: function (xhr, status, err) {

}

});

});

 

My Code in Asp.net MVC is 

[HttpPost]

public string Greetings(List postData)

{

string result = "";

foreach(var item in postData)

{

result += item + " ";

}

return result;

}