Allow Employee to mark attendance once per day ASP.NET MVC

Question

I'm new to ASP.NET MVC. In my Attendance management system, There are no. of employees marking their attendance on a daily basis. I want to restrict employee to mark only one attendance per day. I've done a lot of search but nothing find anything accurate.

 

Here's my Controller Code to Create Attendance

DateTime todayDate = Convert.ToDateTime(DateTime.Now.ToString("dd MM yyyy"));
[Authorize]
public ActionResult Create() {
Employee employee = JsonConvert.DeserializeObject<Employee>(User.Identity.Name);
return View(new Attendance() { Emp_Id = employee.Emp_Id });
}
[HttpPost]
public ActionResult Create(Attendance attendance)
{
if (ModelState.IsValid)
{
if (attendance.Date =! todayDate)
{
try
{
db.Attendance.Add(attendance);
db.SaveChanges();
}
catch (Exception ex)
{
throw;
}
}
}
return RedirectToAction("Index", "Attendance");
}

And Here's my View Code

@model AttendancePortal2.Models.Attendance
@{
ViewBag.Title = "Index";
}
<div class="container">
<div class="navbar-header">
<h2>Add New Entry</h2>
</div>
<div class="navbar-collapse collapse">
<ul class="nav navbar-nav">
<li>@Html.ActionLink("Log out", "LogOff", "Account")</li>
</ul>
</div>
<hr />
@using (Html.BeginForm("Create", "Attendance", FormMethod.Post))
{
<div class="row">
@Html.HiddenFor(model => model.Emp_Id)
<div class="col-md-3">
<label>Date <span class="text-danger">*</span></label>
<div class="input-group date form_date" data-date="" data-date-format="dd MM yyyy" data-link-field="dtp_input2" data-link-format="yyyy-mm-dd">
@Html.TextBoxFor(model => model.Date, new { @class = "form-control" })
<span class="input-group-addon"><span class="glyphicon glyphicon-remove"></span></span>
<span class="input-group-addon"><span class="glyphicon glyphicon-calendar"></span></span>
</div>
<input type="hidden" id="dtp_input2" value="" /><br />
</div>
<div class="col-md-3">
<label>Check In <span class="text-danger">*</span></label>
<div class="input-group date form_time" data-date="" data-date-format="hh:ii" data-link-field="dtp_input3" data-link-format="hh:ii">
@Html.TextBoxFor(model => model.CheckIn, new { @class = "form-control" })
<span class="input-group-addon"><span class="glyphicon glyphicon-remove"></span></span>
<span class="input-group-addon"><span class="glyphicon glyphicon-time"></span></span>
</div>
<input type="hidden" id="dtp_input1" value="" /><br />
</div>
<div class="col-md-3">
<label>Check Out</label>
<div class="input-group date form_time" data-date="" data-date-format="hh:ii" data-link-field="dtp_input3" data-link-format="hh:ii">
@Html.TextBoxFor(model => model.CheckOut, new { @class = "form-control" })
<span class="input-group-addon"><span class="glyphicon glyphicon-remove"></span></span>
<span class="input-group-addon"><span class="glyphicon glyphicon-time"></span></span>
</div>
<input type="hidden" id="dtp_input3" value="" /><br />
</div>
<div class="col-md-3">
<label>Short Leave (Hours)</label>
@Html.TextBoxFor(model => model.ShortLeave, new { @class = "form-control", Type = "number" })
</div>
</div>
<div class="row">
<div class="col-md-12">
<input type="submit" class="btn btn-primary" value="Mark Attendance" />
@Html.ActionLink("My Attendance", "Index", "Attendance")
</div>
</div>
}
</div>