如何将自定义登录失败通知传递给MVC4中的视图(How to pass a custom login failed notification to the view in MVC4)

 我想在我编写自己的视图中传递错误登录通知，但我不知道如何。 我想把它放在@Html.ValidationMessageFor(model => model.Password)和@Html.ValidationMessageFor(model => model.Password)或一个单独的标签（我是否正确使用@Html.ValidationMessage()而不是@Html.ValidationMessageFor() ？） 
 
 这是我的模特： 
 
public class User 
{
    public int UserId { get; set; }

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

    [Required]
    [DataType(DataType.Password)]
    public string Password { get; set; }
}
 
 这里是我的控制器： 
 
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Login(User p)
{
    if (ModelState.IsValid)
    {
        User item = db.Authenticate(p);

        if (item != null) // if item is not null, the login succeeded
        {
            return RedirectToAction("Main", "Home");
        }
    }
    string error = "Incorrect user name or password."; //  I don't know how to pass this
    return View(); //login failed
}
 
 这是我的看法： 
 
@using (Html.BeginForm()) {
    @Html.AntiForgeryToken()
    @Html.ValidationSummary(true)

    <fieldset>
        <legend>User</legend>

        <div class="editor-label">
            @Html.LabelFor(model => model.UserName)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.UserName)
            @Html.ValidationMessageFor(model => model.UserName)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.Password)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.Password)
            @Html.ValidationMessageFor(model => model.Password)
        </div>

        <p>
            <input type="submit" value="Login" />
        </p>
    </fieldset>
}

I want to pass an error login notification in the view which I coded my self, but I do not know how. I want to put it in the @Html.ValidationMessageFor(model => model.UserName) and @Html.ValidationMessageFor(model => model.Password) or a separate label (am I correct that I will use @Html.ValidationMessage() instead of @Html.ValidationMessageFor()?)
 
here is my model:
 
public class User 
{
    public int UserId { get; set; }

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

    [Required]
    [DataType(DataType.Password)]
    public string Password { get; set; }
}
 
here is my controller:
 
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Login(User p)
{
    if (ModelState.IsValid)
    {
        User item = db.Authenticate(p);

        if (item != null) // if item is not null, the login succeeded
        {
            return RedirectToAction("Main", "Home");
        }
    }
    string error = "Incorrect user name or password."; //  I don't know how to pass this
    return View(); //login failed
}
 
here is my view:
 
@using (Html.BeginForm()) {
    @Html.AntiForgeryToken()
    @Html.ValidationSummary(true)

    <fieldset>
        <legend>User</legend>

        <div class="editor-label">
            @Html.LabelFor(model => model.UserName)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.UserName)
            @Html.ValidationMessageFor(model => model.UserName)
        </div>

        <div class="editor-label">
            @Html.LabelFor(model => model.Password)
        </div>
        <div class="editor-field">
            @Html.EditorFor(model => model.Password)
            @Html.ValidationMessageFor(model => model.Password)
        </div>

        <p>
            <input type="submit" value="Login" />
        </p>
    </fieldset>
}

原文：https://stackoverflow.com/questions/46851142