PlaceHolder in ASP.NET MVC 5.2.3

1) With use of MVC Data Annotations:
     Model:

    [Required]
    [Display(Prompt = "Enter Your First Name")]
    public string FirstName { get; set; }

    Razor Syntax:

    @Html.TextBoxFor(m => m.FirstName, new { placeholder = @Html.DisplayNameFor(n => n.UserName)})

2) With use of MVC Data Annotations But with DisplayName:

  Model:

   [Required]
   [DisplayName("Enter Your First Name")]
   public string FirstName { get; set; }  

  Razor Syntax: 

     

@Html.TextBoxFor(m => m.FirstName, new { placeholder = @Html.DisplayNameFor(n => n.UserName)})

3) Without use of MVC Data Annotation (recommended):

 @Html.TextBoxFor(m => m.FirstName, new { @placeholder = "Enter Your First Name")