如何从 controller 传递数据以在 MVC 中的 JQuery AJAX 调用期间查看？

Question

In my view, I have an AJAX call which sends an id parameter to my controller. This bit works fine. In my controller, I plan to query the database with that id, pull out associated data and want to send this back to the AJAX call/view. This is the bit I am struggling with, as I am new to AJAX calls.

var chosenSchoolID = $("#SelectedSchoolId").val();

$.ajax({
  url: "/Home/GetSchoolDetailsAJAX",
  type: "POST",
  data: {
    schoolID: chosenSchoolID
  },
  dataType: "text",
  success: function(data) {
    if (data == "success") {

    }
  },
  error: function(data) {
    if (data == "failed")
      alert("An error has occured!");
  }
});

The above is my AJAX call, and this does hit my controller method. However in my controller, I want to now send back other string data and I am unsure on how to do this (just placeholder code currently)

[HttpPost]
public ActionResult GetSchoolDetailsAjax(string schoolID)
{
  // query database using schoolID
  // now we have other data such as:
  string SchoolName = "";
  string SchoolAddress = "";
  string SchoolCity = "";
  return null;
}

Must I declare variables in my Jquery and pass into the data parameter of the AJAX call in order for the values to be passed?

Many thanks in advance

Answer 1

The simplest way to do this is to return the entities retrieved from your database using return Json() from your controller.

Note that when retrieving data then a GET request should be made, not a POST. In addition the default MVC configuration should have the routes setup to allow you to provide the id of the required resource in the URL. As such, try this:

$.ajax({
  url: "/Home/GetSchoolDetailsAJAX/" + $("#SelectedSchoolId").val(),
  type: "get",
  success: function(school) {
    console.log(school);
  },
  error: function() {
    alert("An error has occured!");
  }
});

[HttpGet]
public ActionResult GetSchoolDetailsAjax(string id) {
  var school = _yourDatabaseContext.Schools.Single(s => s.Id == id); // assuming EF
  return Json(school);
}

If you'd like to test this without the database integration, amend the following line:

var school = new {
  Id = id,
  Name = "Hogwarts",
  Address = "Street, City, Country"
};