asp.net mvc Razor TextBox

问题:

How do you check the value that has been entered in an ASP.NET MVC @Html.TextBox and compare it with a value in the database? I want to make an easy login, and want to see if the value that has been entered in the textbox is the same as that in the database

<tr><td>Username</td><td>:</td><td>@Html.TextBox("username", new { @value = ViewBag.username })</td></tr>

I tried things like creating a viewbag and then taking it to the controller, but it didnt seem to work.

回答1:

Create a viewmodel(a simple class) for this specific UI

public class LoginViewModel
{
  [Required]
  public string UserName { set;get;}

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

Now in your GET action, create an object of this class and send to your view.

public ActionResult Login()
{
  var vm=new LoginViewMode();
  return View(vm);
}

Now in our login view(Login.cshtml)which is strongly typed to our LoginViewModel, we will use the TextBoxFor html helper method to render the textboxes for our UserName and Password fields.

@model LoginViewModel
@using(Html.Beginform())
{
  UserName 
  @Html.TextBoxFor(x=>x.UserName);

  Password
  @Html.TextBoxFor(x=>x.Password)
  <input type="submit" />
}

This will render a form which has action attribute value set to /YourCotnroller/Login. now we need to have an HttpPost action method to handle the form posting

[HttpPost]
public ActionResult Login(LoginViewModel model)
{
  if(ModelState.IsValid)
  {
    string uName=model.UserName;
    string pass=model.Password.

    //Now you can use the above variables to check it against your dbrecords.  
    // If the username & password matches, you can redirect the user to 
    //  another page using RedirecToAction method
    //  return RedirecToAction("UserDashboard")

  }
  return View(model);
}
public ActionResult UserDashboard()
{
  //make sure you check whether user is logged in or not
  // to deny direct access without login
  return View();
}

回答2:

Try like this:

Define model property in your Model class:

public class Login{

        [Required]
        [Remote("IsUserNameAvaliable", "Home")]
        public string username{get;set;}

        [Required]
        public string password{get;set;}
}

The Remote attribute that is placed will find the Method/Action with IsUserNameAvaliable in the controller name Home.

The remote attribute servers for this purpose in MVC.

public JsonResult IsUserNameAvaliable(string username)
        {
            //Check if there are any matching records for the username name provided
            if (_dbEntity.Users.Any(c => c.UserName == username))
            {
                //If there are any matching records found

                return Json(true, JsonRequestBehavior.AllowGet);
            }
            else
            {
                string userID = String.Format(CultureInfo.InvariantCulture,
                                "{0} is not available.", username);

                return Json(userID, JsonRequestBehavior.AllowGet);
            }

        }

Now in your view strongly type the textbox

@model Application.Models.Login

@Html.TextBoxFor(m=>m.username)
@Html.ValidationMessageFor(m=>m.username)

Donot forget to include jquery validation scripts.

 @Scripts.Render("~/bundles/jquery")
 @Scripts.Render("~/bundles/jqueryval")