C＃可空与不可空DateTime标签

Question

This is an EPIC story about date and time.

Created is a non-nullable DateTimeOffset variable Updated is a nullable DateTimeOffset variable

Values of both have been created properly, exist in the DB and have been passed to the view. So both of these values should be available within: <div class="row">@Html.Label(Model.Created.Value.ToString("MMMM, dd yyyy hh:mm tt"))</div> <div class="row">@Html.Label(Model.Updated.Value.ToString("MMMM, dd yyyy hh:mm tt"))</div>

However the second (Updated) is good-to-go and the first(Created) pulls an error: "ValueExtensions.Value(HtmlHelper, string)' is a method, which is not valid in the given context"

It occurs on the .value part. Why is one ok and the other not? What would the nullability of the variable have to do with it being acceptable? or make the method 'not valid in the given context'?

My Model:

 public BlogPost()
    {
        this.Comments = new HashSet<Comment>();
    }

    public int Id { get; set; }

    public DateTimeOffset Created { get; set; }
    public DateTimeOffset? Updated { get; set; }

    [Required()]
    public string Title { get; set; }
    public string Slug { get; set; }
    [Required()]
    [AllowHtml]
    public string Body { get; set; }
    public string MediaURL { get; set; }
    public bool Published { get; set; }

    public virtual ICollection<Comment> Comments { get; set; }

Answer 1

Nullable type values can be accessed with .Value .

Non-nullable types do not have .Value .

Since Model.Created is not Nullable, you would access it's value simply by calling Model.Created .

Read up on the Nullable Structures here .

Answer 2

You have two typo's. Firstly the extra > on the between div and class, secondly non-nullable objects don't have a Value property.

Try this:

<div class="row">
  @Html.Label(Model.Created.ToString("MMMM, dd yyyy  hh:mmtt"))
</div>