Question

我有一个表格＆＃34; MovieForm＆＃34;用于将电影添加到数据库。当我填写所有必需的输入并按下保存按钮时，电影正常添加到数据库。如果我先将一个或多个必需输入留空，然后按save，我会收到DataAnnotations错误消息，＆＃34; ModelState.isValid＆＃34;变得虚假，并将我重新定向到我已经使用此代码的相同形式：

[HttpPost]
public ActionResult Save(Movie movie)
{
    if (!ModelState.IsValid)
    {  
        return View("MovieForm");
    }

  //logic for saving movie 
}

以及它应该如何完成。此操作后会出现问题。现在，当我填写所有必需的输入并再次按下保存按钮时，ModelState.IsValid没有更新，它仍然是假的，所以我陷入了这个if语句。

如何重置它，以便再次检查是否符合要求？

型号：

public class Movie
{
    [Key]
    public Guid MovieID { get; set; }

    [Required]
    [StringLength(40)]
    public string Title { get; set; }

    [Required]
    [StringLength(60)]
    public string Director { get; set; }

    [Required]
    [StringLength(256)]
    public string Actors { get; set; }
}

查看

@using Cinema.Models
@model Cinema.Models.Movie

@using (Html.BeginForm("Save", "Movies", FormMethod.Post, new { @class = "form-horizontal", role = "form" }))
{
<div class="form-group">
    @Html.LabelFor(m => m.Title, "Title", new { @class = "col-md-2 control-label" })
    <div class="col-md-8">
        @Html.TextBoxFor(m => m.Title, new { @class = "form-control col-md-4" })
        @Html.ValidationMessageFor(m => m.Title, "", new { @class = "text-danger col-md-4 form-control-static" })
    </div>
 </div>
<div class="form-group">
    @Html.LabelFor(m => m.Director, "Director", new { @class = "col-md-2 control-label" })
    <div class="col-md-8">
        @Html.TextBoxFor(m => m.Director, new { @class = "form-control col-md-4" })
        @Html.ValidationMessageFor(m => m.Director, "", new { @class = "text-danger col-md-4 form-control-static" })
    </div>
</div>
<div class="form-group">
    @Html.LabelFor(m => m.Actors, "Actors ", new { @class = "col-md-2 control-label" })
    <div class="col-md-8">
        @Html.TextBoxFor(m => m.Actors, new { @class = "form-control col-md-4" })
        @Html.ValidationMessageFor(m => m.Actors, "", new { @class = "text-danger col-md-4 form-control-static" })
    </div>
</div>

@Html.HiddenFor(m => m.MovieID)

<div class="form-group">
    <div class="col-md-offset-2 col-md-4">
        <input type="submit" class="btn btn-default" value="Save" />
        <a class="col-md-offset-1" href="/Movies/">cancel</a>
    </div>
</div>
}

Answer 1

您可以通过在调试模式下扩展它来检查ModelState对象中的错误

Answer 2

Stephen's suggestion in his comment gives a very nice succinct way of filtering the ModelState to see what is causing errors. I did something similar (though rather longer winded) to combine them in a single string for easy viewing/copying/pasting. Try adding this to your controller:

    string modelErrors = GetModelStateErrors(ModelState);

That calls this method:

    public string GetModelStateErrors(ModelStateDictionary ms)
    {
        StringBuilder errors = new StringBuilder();
        foreach (string k in ms.Keys)
        {
            if (ms[k].Errors.Count > 0)
            {
                errors.Append($"\n{k}:\n");
                foreach (var e in ms[k].Errors)
                {
                    errors.Append($"   {e.ErrorMessage}\n");
                }
            }
        }
        return errors.ToString();
    }

将输入字段更改为有效输入后，ModelState.IsValid不会更新

2 个答案: