ASP.NET Core : How to login with “UserName” instead of “Email”?

The first step is to scaffold identity to your application :

Scaffold Identity in ASP.NET Core projects

Then you could customize the Register.cshtml/Register.cshtml.cs and Login.cshtml/Login.cshtml.cs , update model and view , and change the logic in OnPostAsync function to fit your requirement .

To your requirement , you can follow the steps :

1. Scaffold identity into your project .

2. Modify the Register.cshtml.cs , add Username to InputModel :

   [Required]
   [DataType(DataType.Text)]
   [Display(Name = "User Name")]
   public string UserName { get; set; }
   

3. Modify the OnPostAsync method :

   var user = new IdentityUser { UserName = Input.UserName, Email = Input.Email };
   

4. Update the Register.cshtml to include the UserName :

   <div class="form-group">
       <label asp-for="Input.UserName"></label>
       <input asp-for="Input.UserName" class="form-control"/>
       <span asp-validation-for="Input.UserName" class="text-danger"></span>
   </div>
   

5. Modify the Login.cshtml.cs , modify InputModel to replace Email with UserName :

   [Required]
   [DataType(DataType.Text)]
   [Display(Name = "User Name")]
   public string UserName { get; set; }
   

6. Modify the Login.cshtml :

   <div class="form-group">
       <label asp-for="Input.UserName"></label>
       <input asp-for="Input.UserName" class="form-control" />
       <span asp-validation-for="Input.UserName" class="text-danger"></span>
   </div>
   

7. Modify the Login.cshtml.cs OnPostAsync method to use Username instead of email :

   var result = await _signInManager.PasswordSignInAsync(Input.UserName, Input.Password, Input.RememberMe, lockoutOnFailure: true);
   

By default ASP.NET Identity uses FindByNameAsync to check if user with given name exists , so that you don't need to override PasswordSignInAsync function in SignInManager . If you want to login with email , your could click here to update that .

Look inside Pages -> Login.cshtml page (Here, you will get a class named Login.cshtml.cs). Inside that class, you will get a method named 'OnPostAsync'

Change frontend as likes

And inside your 'Login.cshtml.cs' class change this method with your target Dashboard/Index url..

 public async Task<IActionResult> OnPostAsync()
    {
        if (ModelState.IsValid)
        {
            var validated = _ADService.Validate(new NetworkCredential(LoginData.UserId, LoginData.Password));
            if (validated)
            {
                if (await _identityService.SignInAsync(HttpContext, LoginData.UserId))
                {

              //   return Redirect("Index");
                   return Redirect("../app/bootstrap.html");

                }

                ModelState.AddModelError("", "account does not exist in system!");
                return Page();
            }

            ModelState.AddModelError("", "userid or password is invalid!");
            return Page();
        }
        else
        {
            ModelState.AddModelError("", "userid or password is blank!");
            return Page();
        }
    }

When using the excepted answer I also had to modify the following line in step three from Input.Email to Input.UserName on the latest ASP.NET Core template.

await _userStore.SetUserNameAsync(user, Input.UserName, CancellationToken.None);