验证有效，但未显示消息

Posted 2023-04-13

【中文标题】验证有效，但未显示消息

【英文标题】：Validation works but message is not displayed

【发布时间】：2021-08-08 15:43:53

【问题描述】：

我正在尝试在提交表单之前验证模型中的特定字段。它可以工作但没有显示消息，这是因为名称属性不匹配。

这是我的模型：

    public class TaskList

    [Key]
    public int Id  get; set; 

    [MaxLength(200, ErrorMessage = "Subject field can't have more than 250 characters.")]
    [Required(ErrorMessage = "Subject field cannot be empty.")]
    [Column(TypeName = "nvarchar")]
    public string Subject  get; set; 
    [MaxLength(1000, ErrorMessage = "Details field can't have more than 1000 characters.")]
    [Column(TypeName = "nvarchar")]
    public string Details  get; set; 
    [Required(ErrorMessage = "Please select a module.")]
    public TaskLabels Label  get; set; 
    [Required]
    [Column(TypeName = "date")]
    public DateTime Created  get; set; 
    [Column(TypeName = "date")]
    public DateTime? DueDate  get; set; 
    [Column(TypeName = "date")]
    public DateTime? Completed  get; set; 

这是控制器动作：

 [HttpPost]
    public IActionResult TaskList(TaskList newTask)
    
            _ticketRepo.AddTask(newTask);
            return RedirectToAction("TaskList");
    

这是我的视图模型：

    public class TaskListViewModel

    public TaskList ToDo  get; set; 
    public IEnumerable<TaskList> TasksList  get; set; 

这是我的表格：

<div class="modal fade" id="modal-add">
<div class="modal-dialog modal-lg">
    <form class="form-horizontal" asp-controller="home" asp-action="TaskList" method="post">
        <div class="modal-content">
            <div class="modal-header bg-success">
                <h4 class="modal-title">Add New To Do Item</h4>
                <button type="button" class="close" data-dismiss="modal" aria-label="Close">
                    <span aria-hidden="true">&times;</span>
                </button>
            </div>
            <div class="modal-body">
                <div class="card-body">
                    <div class="form-group row">
                        <label asp-for="ToDo.Subject" class="col-sm-2 col-form-label">Subject</label>
                        <div class="col-sm-10">
                            <input type="text" asp-for="ToDo.Subject" name="Subject" class="form-control" placeholder="Subject">
                            <span asp-validation-for="@Model.ToDo.Subject" class="text-danger"></span>
                        </div>
                    </div>
                    <div class="form-group row">
                        <label asp-for="ToDo.Details" class="col-sm-2 col-form-label">Details</label>
                        <div class="col-sm-10">
                            <textarea asp-for="ToDo.Details" name="Details" class="form-control" placeholder="Provide some details about the task."></textarea>
                            <span asp-validation-for="ToDo.Details" class="text-danger"></span>
                        </div>
                    </div>
                    <div class="form-group row">
                        <label asp-for="ToDo.Label" class="col-sm-2 col-form-label">Module</label>
                        <div class="col-sm-10">
                            <select name="ToDo.Label" asp-for="Label" asp-items="html.GetEnumSelectList<TaskLabels>()" class="form-control select2 select2-danger" data-dropdown-css-class="select2-danger" style="width: 100%;">
                                <option value="" selected="selected">Please select one</option>
                            </select>
                            <span asp-validation-for="ToDo.Label" class="text-danger"></span>
                        </div>
                    </div>
                    <div class="form-group row">
                        <label asp-for="ToDo.DueDate" class="col-sm-2 col-form-label">Date:</label>
                        <div class="col-sm-10 input-group date" id="duedate" data-target-input="nearest">
                            <input type="text" name="DueDate" asp-for="ToDo.DueDate" class="form-control datetimepicker-input" data-target="#duedate" />
                            <div class="input-group-append" data-target="#duedate" data-toggle="datetimepicker">
                                <div class="input-group-text"><i class="fa fa-calendar"></i></div>
                            </div>
                        </div>
                    </div>
                    <div asp-validation-summary="All" class="text-danger"></div>
                </div>
                <!-- /.card-body -->
            </div>
            <div class="modal-footer justify-content-between">
                <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
                <button type="submit" class="btn btn-primary">Save changes</button>
            </div>
        </div>
        <!-- /.modal-content -->
    </form>
</div>
<!-- /.modal-dialog -->

<script src="~/lib/jquery-validation/dist/jquery.validate.min.js"></script><script src="~/lib/jquery-validation-unobtrusive/jquery.validate.unobtrusive.min.js"></script>

在我的表单中，如果我从输入字段中删除 name 属性，则验证有效，验证消息会显示，但模型绑定不起作用，并且我的属性出现空异常错误。我做错了什么？

【参考方案1】：

当然，我必须在我的控制器动作中实例化视图模型！当我这样做并从我的视图中的输入字段中删除所有名称属性时，一切正常！

    [HttpPost]
    public IActionResult TaskList(TaskListViewModel model)
    

        if (ModelState.IsValid)
        
            TaskList taskList = new TaskList
            
                Created = DateTime.Now.Date,
                Subject = model.ToDo.Subject,
                Details = model.ToDo.Details,
                DueDate = model.ToDo.DueDate,
                Label = model.ToDo.Label
            ;

            _ticketRepo.AddTask(taskList);
            return RedirectToAction("TaskList");
        
        else
        
            return View();