Question

Here is my ajax call

$.ajax({
            type: "POST",
            url: "MyMethod",
            contentType: 'application/json; charset=utf-8',
            data: JSON.stringify({  Param1: 'value1', Param2: 'value2'}),
            success: function (msg) { location.href = '@Url.Action("MyActionMethod", "MyController")'; },
            error: function (msg) { alert(msg); }
        });

This is my model

public class MyModel
{
    public string Param1 { get; set; }
    public string Param2 { get; set; }
}

MyMethod implementation is as follows

public bool MyMethod(MyModel model)
{

    if (!ValidateModel(model) )
    {
        // I want to error a descriptive error  
        return false;
    }

    // Some other processing
    return true;
}

Problem is that I don’t know how does it determine if call is a success or failure. Returning ture/false does not seem to help as code always go in the success code path (that is it redirects to MyController.MyActionMethod). Any ideas what i am doing wrong

Answer 1

This is usually what I do:

public JsonResult MyMethod(MyModel model)
{
    var success = true;
    var result = string.Empty;

    if (!ValidateModel(model) )
    {
        // I want to error a descriptive error  
        success = false;
        result = "Invalid model";
    }

    // Some other processing
    return Json(new { success = success, error = result }, 
        JsonRequestBehavior.Allow);
}

Note the change in the return method from bool to JsonResult. And then in your JavaScript you could test the properties coming through on the JSON object:

...
success: function (msg) { 
   if (msg.success) {
       location.href = '@Url.Action("MyActionMethod", "MyController")'; 
   } else {
       alert(msg.error);
   }
},
...