ASP.NET AJAX无法找到控制器，请求技术解决方案

Hey there, I see you’ve spent 3 hours troubleshooting this AJAX-to-controller issue—let’s break this down and fix it step by step!

First, here's your project structure for reference:

HomeController.cs Code #

(Quick heads-up: Your code has a duplicate public class HomeController : Controller line—be sure to remove that extra declaration to avoid compilation errors!)

public class HomeController : Controller 
{ 
    [WebMethod] 
    public static int OnSubmit() 
    { 
        return 1; 
    } 

    [HttpGet] 
    public ActionResult Index() 
    { 
        return View("Index"); 
    } 
}

Index.cshtml AJAX Script (Partial) #

<script type="text/javascript"> 
function sendRequest() { 
    // Your incomplete AJAX logic here
}
</script>

The main problems here stem from mixing WebForms and MVC patterns—they don’t play nice together:

• [WebMethod] is a WebForms-specific attribute; it won’t work in an MVC Controller. MVC uses action methods with HTTP verb attributes (like [HttpPost]) instead.
• Static methods can’t be used as MVC action methods by default—MVC relies on controller instances to handle requests.
• You haven’t specified an HTTP verb for your OnSubmit method, and AJAX calls typically use POST (not GET) for form/submit actions.

Updated HomeController.cs #

Replace the WebForms-style code with proper MVC conventions:

public class HomeController : Controller 
{ 
    // Replace [WebMethod] with MVC's [HttpPost], remove static modifier
    [HttpPost]
    public ActionResult OnSubmit() 
    { 
        // Return JSON for clean AJAX handling (more flexible than raw int)
        return Json(1);
        // If you strictly need a plain integer response, use:
        // return Content("1", "text/plain");
    } 

    [HttpGet] 
    public ActionResult Index() 
    { 
        return View("Index"); 
    } 
}

Complete Working AJAX Script (jQuery Example) #

Assuming you’re using jQuery (the most common AJAX library for MVC), here’s a full, tested sendRequest function:

<script src="~/Scripts/jquery-3.7.1.min.js"></script> <!-- Make sure jQuery is loaded first! -->
<script type="text/javascript"> 
function sendRequest() { 
    $.ajax({
        url: '@Url.Action("OnSubmit", "Home")', // Use MVC's URL helper to avoid hardcoding paths
        type: 'POST',
        contentType: 'application/json; charset=utf-8',
        success: function(response) {
            console.log("Success! Response:", response);
            // Add your post-success logic here (e.g., alert("Returned: " + response))
        },
        error: function(xhr, status, error) {
            console.error("Request failed:", error);
            // Handle errors here (e.g., alert("Something went wrong!"))
        }
    });
}
</script>

• Always use @Url.Action to generate controller/action URLs—this avoids broken links when deploying to different environments.
• If you need to pass data to the controller, add parameters to the OnSubmit method and include a data property in your AJAX call (e.g., data: JSON.stringify({username: "Zeal"})).
• Double-check that jQuery is loaded before your AJAX script—missing jQuery is a super common gotcha!

内容的提问来源于stack exchange，提问作者ZeáL