在复选框

Question

我在函数中有一个复选框下拉列表。因此用户可以选择一个，多个或零。当用户选择一个或多个时，一切都是正确的。但是当用户不选择任何我有空指针异常时。为了处理这个异常，我想默认情况下，如果他没有选择任何东西来显示所有的结果（如果他选择全部）。我怎么能这样做？

这是JS函数

  $(function () {
      $("#datepicker").datepicker({
          //defaultDate: "+1w",
          changeMonth: true,
          changeYear: true,
          numberOfMonths: 1,
          minDate: "01/01/2008"
      })
      .datepicker('setDate', new Date());
      $("button.action").click(function () {
          //var users = new Array();
          var date = $('#datepicker').val().toString();
          var selected_values = new Array();
          //var userName = $(' .checked:checked').val();
          $(document).ready(function () {
              selected_values = []; // initialize empty array 
              $(".checked:checked").each(function () {
                  selected_values.push($(this).val());
              });
          });
          $.ajax({
              url: 'EmployeeDate',
              datatype: "application/json",
              traditional:true, 
              data: {
                  lstUserName: selected_values,
                  strDate: date
              },
              success: function (data, textStatus, jqXHR) {
                  $('#DataUser').html(data);
              },
              error: function () {
                  console.log("error handler when ajax request fails... ");
              },

          });
      });
  });

这是控制器：

public IEnumerable<DateTime> getInfoByDate(string strDate, string[] lstUserName)
{
    CareDB context = new CareDB();
    IEnumerable<DateTime> lst = null;
    List<DateTime> model = new List<DateTime>();

    if (lstUserName != null)
    {
        foreach (string user in lstUserName)
        {
            SqlParameter userName = new SqlParameter("@EmployeeName", user);
            SqlParameter Date = new SqlParameter("@Date", strDate);
            object[] parameters = new object[] { Date, userName };

            model.Add(context.ReleaseDate.SqlQuery("_UserInformationByDate @Date, @EmployeeName", parameters).ToList().FirstOrDefault());
        }
    }
    else
    {
        SqlParameter Date = new SqlParameter("@Date", strDate);
        SqlParameter userName = new SqlParameter("@EmployeeName", lstUserName);

        object[] parameters = new object[] { Date, userName };

        model = context.ReleaseDate.SqlQuery("_UserInformationByDate @Date, @EmployeeName", parameters).ToList();
    }
    context.Dispose();
    context = null;
    return model;
}

Answer 1

试试这个

     $(document).ready(function () {
                  selected_values = []; // initialize empty array 

                  // nothing selected so push all value regadless
                  if( $(".checked:checked").length == 0)
                  {
                     $(".checked").each(function () {
                      selected_values.push($(this).val());
                      });
                  }
                else
                {
                  $(".checked:checked").each(function () {
                      selected_values.push($(this).val());
                  });
                  });
               }