AmbiguousActionException: Multiple actions matched. The following actions matched route data and had all constraints satisfied:

Question

I know there have been more questions about this, but they dont seem to work for me.

I followed the following tutorial: https://www.youtube.com/watch?v=hlZexx2gbNs.

I want to make an email send form in MVC ASP.NET. Everything in seemed to work, except for the last step. I had to change the RouteConfig, but I dont have a routeconfig.

I think I need to change this for this to work, but I dont know where to change this. Does anyone have any idea how to solve this issue?

If there is a good solution for this on another question, let me know.

This is de code I use for the view:

@model smoothboard.Models.gmail

@{
ViewData["Title"] = "Index";
}

<h2>Index</h2>

<h4>Email</h4>
<hr />

<div>
    @using (Html.BeginForm("Index", "EmailSetup", FormMethod.Post, new { enctype = "multipart/form-data" }))
    {
    <table>
        <tr>
            <td>
                Naar:
            </td>
            <td>
                @Html.TextBoxFor(gmail=>gmail.To)
            </td>
        </tr>
        <tr>
            <td>
                <input type="submit" value="Verzend">
            </td>
        </tr>
    </table>
    }
</div>

<div>
    <a asp-action="Index">Back to List</a>
</div>

This is the code I use to send the mail:

public class EmailSetupController : Controller
{
    public IActionResult Index()
    {
        return View();
    }
    string from = new string("[email protected]");
    string subject = new string("Geregistreerd");
    string body = new string("Je hebt je ingeschreven voor de nieuwsbrief!");
    public IActionResult Index(smoothboard.Models.gmail gmail, string from)
    {

        MailMessage mm = new MailMessage(from, gmail.To);
        mm.Subject = subject;
        mm.Body = body;
        mm.IsBodyHtml = false;

        SmtpClient smtp = new SmtpClient();
        smtp.Host = "smtp.gmail.com";
        smtp.Port = 587;
        smtp.EnableSsl = true;

        NetworkCredential nc = new NetworkCredential("[email protected]", "hans1234hans");
        smtp.UseDefaultCredentials = true;
        smtp.Credentials = nc;
        smtp.Send(mm);
        ViewBag.MailMessage = "Mail is verzonden";
        return View();
    }
}

This is what I use for my model:

namespace smoothboard.Models
{
public class gmail
{
    public string To { get; set; }
}
}

Answer 1

The problem mentioned by exception message is straightforward: you have 2 action methods with same name and same HTTP method (by default HTTP method is GET, which implicitly uses [HttpGet]):

// first action with GET method
public IActionResult Index() { ... }

// ambiguous matching here because this also uses GET method
public IActionResult Index(smoothboard.Models.gmail gmail, string from) { ... }

Since you have BeginForm helper which uses FormMethod.Post:

@using (Html.BeginForm("Index", "EmailSetup", FormMethod.Post, new { enctype = "multipart/form-data" }))

Then you must decorate the second Index action with parameters using [HttpPost] attribute to distinguish its HTTP method:

[HttpPost]
public IActionResult Index(smoothboard.Models.gmail gmail, string from)
{
    MailMessage mm = new MailMessage(from, gmail.To);
    mm.Subject = subject;
    mm.Body = body;
    mm.IsBodyHtml = false;

    SmtpClient smtp = new SmtpClient();
    smtp.Host = "smtp.gmail.com";
    smtp.Port = 587;
    smtp.EnableSsl = true;

    NetworkCredential nc = new NetworkCredential("[email protected]", "hans1234hans");
    smtp.UseDefaultCredentials = true;
    smtp.Credentials = nc;
    smtp.Send(mm);
    ViewBag.MailMessage = "Mail is verzonden";
    return View();
}