I'm not able to get ReturnUrl to work on HttpPost using ASP.NET Core 6 MVC.

When adding a breakpoint to the POST method, returnurl is always null. But with .NET 5, it works with the same code setup except that with .NET 6, I need to make the returnurl parameter nullable so that I won't get an error "returnurl field is required".

This is the code I'm using - any help would be much appreciated.

Thanks.

Model:

namespace IdentityManagerDotNet6.Models
{
    public class LoginViewModel
    {
        [Required]
        [EmailAddress]
        public string Email { get; set; } = string.Empty;

        [Required]
        [DataType(DataType.Password)]
        public string Password { get; set; } = string.Empty;

        [Display(Name = "Remember me?")]
        public bool RememberMe { get; set; }
    }
}

Controller

[HttpGet]
public IActionResult Login(string? returnurl)
{
    ViewData["ReturnUrl"] = returnurl;
    return View();
}

[HttpPost]
[ValidateAntiForgeryToken]
public async Task<IActionResult> Login(LoginViewModel loginViewModel, string? returnurl)
{
    ViewData["ReturnUrl"] = returnurl;
    returnurl = returnurl ?? Url.Content("~/");

    if (ModelState.IsValid)
    {
        var result = await _signInManager.PasswordSignInAsync(loginViewModel.Email, loginViewModel.Password, loginViewModel.RememberMe, lockoutOnFailure: true);

        if (result.Succeeded)
        {
            return LocalRedirect(returnurl);
        }

        if (result.IsLockedOut)
        {
            return View("Lockout");
        }
        else
        {
            ModelState.AddModelError(string.Empty, "Invalid login attempt.");
            return View(loginViewModel);
        }
    }

    return View(loginViewModel);
}

View:

@model LoginViewModel

<h1 >Log in</h1>
<div >
    <div >
        <form asp-controller="Account" asp-action="Login" asp-route-returnurl="@ViewData["ReturnUrl"]" method="post" role="form">
            <h4>Use a local account to log in</h4>
            <hr />
            <div asp-validation-summary="All" ></div>
            <div >
                <label asp-for="Email" ></label>
                <div >
                    <input asp-for="Email"  />
                    <span asp-validation-for="Email" ></span>
                </div>
            </div>
            <div >
                <label asp-for="Password" ></label>
                <div >
                    <input asp-for="Password"  />
                    <span asp-validation-for="Password" ></span>
                </div>
            </div>
            <div >
                <input  asp-for="RememberMe" type="checkbox" value="" id="flexCheckChecked">
                <label  asp-for="RememberMe" for="flexCheckChecked">
                    Remember me?
                </label>
            </div>
            <div >
                <div >
                    <button type="submit" asp-controller="Account" asp-action="Login" >Login</button>
                </div>
            </div>
            <p>
                <a asp-action="Register">Register as a new user?</a>
            </p>
            <p>
                <a asp-action="ForgotPassword">Forgot your passord?</a>
            </p>
        </form>
    </div>
</div>

CodePudding user response：

"I'm not able to get ReturnUrl to work on HttpPost using ASP.NET Core 6 MVC.":

I have checked your code between the line. It doesn't has anything wrong with [FromQuery] So you don't need to do anything on [FromQuery] as other answer I've seen, may be deleted now.

Issue Replication:

I have reproduced your issue successfully as you can see below:

What Causing the Issue:

If you investigate your code again you would noticed that you are using asp-controller="Login" asp-action="Login" twice on your Login.cshtml at the begining of the form and at the point of submit button this causing the data loss while you are submitting the form.

At the starting on form:

   <form asp-controller="Login" asp-action="Login" asp-route-returnurl="@ViewData["ReturnUrl"]" method="post" role="form">

At your button submit::

 <button type="submit" asp-controller="Login" asp-action="Login" >Login</button>

Solution:

The easiest solution is just modify your submit button code like below which will resolve your issue:

            <div >
                <div >
                    <button type="submit" >Login</button>
                </div>
            </div>

Output:

Hope it will resolve your returnurl null issue completely.