C# Asp.net核心Razor考勤创建页面在创建新员工的同时节省员工的考勤时间。如何修复它？

当我试图保存现有员工的考勤时，考勤页面试图创建一个新员工，其姓名字段中的值为空。由于名称字段设置为不为空，因此其失败并显示错误消息

员工表

Database Used: MySql Server
DotNet Core Version = 2.2
Platform: Windows 10 IIS

考勤创建页面

[Table("Attendance")]
    [Display(Name = "Attendance",Description = "Registers Employee Attendance")]
    public class Attendance
    {

        [Key]
        [Column("Attendance Id")]
        [Display(Name = "Attendance Id")]
        public int AttendanceId { get; set; }

        [ForeignKey("EmployeeId")]
        [Column("Employee")]
        [Display(Name = "Employee")]
        public string Employee { get; set; }

        public bool Check{ get; set; }

        [Column("AttendanceTime")]
        [Display(Name = "Attendance Time",AutoGenerateField = true)]
        [DisplayFormat(DataFormatString = "{0:dddd, dd/MM/yyyy, h:mm:ss tt}")]
        [Timestamp]
        public DateTime AttendanceTime { get; set; }

        [ForeignKey("Employee")]
        public virtual Employee Employees { get; set; }
    }

公共类CreateModel:PageModel
{
private readonly Data.payroll\u app\u context\u context；
公共CreateModel（Data.payroll\u app\u上下文）
{
_上下文=上下文；
}
公共IActionResult OnGet（）
{
ViewData[“Employee”]=新建选择列表（_context.Employee，“EmployeeId”，“EmployeeName”）；
返回页（）；
}
[BindProperty]
公众参与度DailyRegister参与度DailyRegister{get；set；}
公共异步任务OnPostAsync（）
{
//对捕获错误进行了注释。
/*如果（！ModelState.IsValid）
{
返回页（）；
}*/
_Add（AttendanceDailyRegister）；
wait_context.SaveChangesAsync（）；
返回页首（“/索引”）；
}
}

考勤管理器CSHTML页面

public class CreateModel : PageModel
    {
        private readonly Data.payroll_app_context _context;

        public CreateModel(Data.payroll_app_context context)
        {
            _context = context;
        }

        public IActionResult OnGet()
        {
        ViewData["Employee"] = new SelectList(_context.Employee, "EmployeeId", "EmployeeName");
            return Page();
        }

        [BindProperty]
        public AttendanceDailyRegister AttendanceDailyRegister { get; set; }

        public async Task<IActionResult> OnPostAsync()
        {
            //Commented for catching errors.
            /*if (!ModelState.IsValid)
            {
                return Page();
            }*/

            _context.AttendanceDailyRegister.Add(AttendanceDailyRegister);
            await _context.SaveChangesAsync();

            return RedirectToPage("./Index");
        }
    }

@page
@model razor.Pages.Attention.CreateModel
@{
ViewData[“标题”]=“创建”；
Layout=“~/Pages/Shared/_Layout.cshtml”；
}
创造
出勤

@DisplayNameFor（model=>model.attention.Check）
返回列表
@节脚本{
@{wait Html.RenderPartialAsync（“_validationScript”）；}
}

---

在此页面中，在保存现有员工的新出勤时间的同时，创建新员工。我修不好。请帮帮我。

我刚换了考勤表，问题就解决了。虽然我不清楚它是怎么解决的

@page
@model razor.Pages.attendance.CreateModel

@{
    ViewData["Title"] = "Create";
    Layout = "~/Pages/Shared/_Layout.cshtml";
}

<h1>Create</h1>

<h4>Attendance</h4>
<hr />
<div class="row">
    <div class="col-md-4">
        <form method="post">
            <div asp-validation-summary="ModelOnly" class="text-danger"></div>
            <div class="form-group">
                <label asp-for="Attendance.Employee" class="control-label"></label>
                <select asp-for="Attendance.Employee" class ="form-control" asp-items="ViewBag.Employee"></select>
            </div>
            <div class="form-group form-check">
                <label class="form-check-label">
                    <input class="form-check-input" asp-for="Attendance.Check" /> @Html.DisplayNameFor(model => model.Attendance.Check)
                </label>
            </div>
            <div class="form-group">
                <input type="submit" value="Create" class="btn btn-primary" />
            </div>
        </form>
    </div>
</div>

<div>
    <a asp-page="Index">Back to List</a>
</div>

@section Scripts {
    @{await Html.RenderPartialAsync("_ValidationScriptsPartial");}
}

---

\u context.AttendanceDailyRegister.Add（AttendanceDailyRegister）

将实体添加到上下文中。它不会自动更新现有实体。您必须首先检索现有实体并更新该实体。还请注意，您不应该将数据库模型用作请求参数，因为这将有效地打开许多安全漏洞。对从Razor页面检索的参数使用单独的模型。确定。我将使用单独的模型来保存数据。但这里的主要问题是，我并不是在试图更新现有的数据。我正在尝试根据现有员工的日期保存新的考勤数据。而是创建新员工。然后确保未设置新实体的Id，以便将其理解为新实体。谢谢您的帮助。

@page
@model razor.Pages.attendance.CreateModel

@{
    ViewData["Title"] = "Create";
    Layout = "~/Pages/Shared/_Layout.cshtml";
}

<h1>Create</h1>

<h4>Attendance</h4>
<hr />
<div class="row">
    <div class="col-md-4">
        <form method="post">
            <div asp-validation-summary="ModelOnly" class="text-danger"></div>
            <div class="form-group">
                <label asp-for="Attendance.Employee" class="control-label"></label>
                <select asp-for="Attendance.Employee" class ="form-control" asp-items="ViewBag.Employee"></select>
            </div>
            <div class="form-group form-check">
                <label class="form-check-label">
                    <input class="form-check-input" asp-for="Attendance.Check" /> @Html.DisplayNameFor(model => model.Attendance.Check)
                </label>
            </div>
            <div class="form-group">
                <input type="submit" value="Create" class="btn btn-primary" />
            </div>
        </form>
    </div>
</div>

<div>
    <a asp-page="Index">Back to List</a>
</div>

@section Scripts {
    @{await Html.RenderPartialAsync("_ValidationScriptsPartial");}
}

[Table("Attendance")]
    [Display(Name = "Attendance",Description = "Registers Employee Attendance")]
    public class Attendance
    {

         private readonly Employee employee;
        [Key]
        [Column("Attendance Id")]
        [Display(Name = "Attendance Id")]
        public int AttendanceId { get; set; }

        [ForeignKey("EmployeeId")]
        [Column("Employee")]
        [Display(Name = "Employee")]
        public string Employee { get; set; }

        public bool Check{ get; set; }

        [Column("AttendanceTime")]
        [Display(Name = "Attendance Time",AutoGenerateField = true)]
        [DisplayFormat(DataFormatString = "{0:dddd, dd/MM/yyyy, h:mm:ss tt}")]
        [Timestamp]
        public DateTime AttendanceTime { get; set; }

        [ForeignKey("Employee")]
        public virtual Employee Employees => employee
    }