ASP.NET

Please, can you help me.

I adapted the example above to asp.net (vb), but it records the same date.

Ex: 08/01/2019 to 08/31/2019, interval of 7 days.

The correct would be to record 08/01 ... 08/08 ... 15/08 ... 22/08 ... 29/08 ... But recorded the 5 days as 01/08.

Follows the code and thanks in advance.

Dim conexao As SqlConnection
Dim cmd As SqlCommand
Dim sql As String

Dim startDate As Date = txtDataCurso.Text
Dim endDate As Date = startDate.AddDays(txtIntervalo.Text) - "This interval is the number of days (end date - initial)"
Dim currDate As Date = startDate

Do While (currDate < endDate)

sql = "INSERT INTO tre_Eventos (Id_Curso, DataEvento) VALUES ('" & ddlCursos.SelectedValue & "', '" & endDate & "')"

currDate = currDate.AddDays(7)

Try

conexao = New SqlConnection(strConn)

conexao.Open()

cmd = New SqlCommand(sql, conexao)

cmd.ExecuteNonQuery()

conexao.Close()

SetFocus(Label1)

Label1.Visible = True
Label1.Text = "Evento Cadastrado com Sucesso"

Catch

SetFocus(Label1)

Label1.Visible = True
Label1.Text = "Ocorreu um erro!" + Err.Description

End Try

Private Sub SearchCustomers()
      Dim constr As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString
      Dim startDate As DateTime
      Dim EndDate As DateTime
      Using con As New SqlConnection(constr)

          Using cmd As New SqlCommand()

              Dim sql As String = "spGetLogs"
              cmd.CommandType = CommandType.StoredProcedure
              cmd.Parameters.AddWithValue("@uuid", suuid.Text)
              cmd.Parameters.AddWithValue("@callerlist", caller_list_id.Text)
              cmd.Parameters.AddWithValue("@phone", phonenumber.Text)
              If DateTime.TryParseExact(date_start.Text, "yyyy-MM-dd HH:mm:ss", Nothing, System.Globalization.DateTimeStyles.None, startDate) Then
                  cmd.Parameters.AddWithValue("@start", startDate)
              Else
                  cmd.Parameters.AddWithValue("@start", DBNull.Value)
              End If
              If DateTime.TryParseExact(date_end.Text, "yyyy-MM-dd HH:mm:ss", Nothing, System.Globalization.DateTimeStyles.None, EndDate) Then
                  cmd.Parameters.AddWithValue("@Endd", EndDate)
              Else
                  cmd.Parameters.AddWithValue("@Endd", DBNull.Value)
              End If
              cmd.Parameters.AddWithValue("@calltype", call_type.SelectedValue)
              'Response.Write(sql)
              'Response.End()
              cmd.CommandText = sql
              cmd.CommandTimeout = 600
              cmd.Connection = con
              Using sda As New SqlDataAdapter(cmd)
                  Dim dt As New DataTable()
                  sda.Fill(dt)
                  gvCustomers.DataSource = dt
                  gvCustomers.DataBind()

              End Using
          End Using
      End Using
  End Sub

In the first DropdownList should display the Countries and in the second should display Cities based on the Country like .. USA then display just cities in USA . well i am getting undefined in dropdown city the Question is why i am getting always undefined in City dropDown list ?

here is countrol :
<pre> public ActionResult Index()
        {
            Details();
            return View();
        }

        public void Details (
        {
            var model = db.GetUniversities().ToList();
            List<SelectListItem> li = new List<SelectListItem>();
            li.Add(new SelectListItem { Text = "Please select Country",Value="0"});
            foreach (var item in model)
            {
                li.Add(new SelectListItem { Text = item.Country, Value = item.Id.ToString()});
                ViewBag.state = li;
            }
        }
        [HttpPost]
        public JsonResult GetCity (int id)
        {
            var ddlCity = db.GetUniversities().Where(x => x.Id == id).ToList();
            List<SelectListItem> licities = new List<SelectListItem>();

            //licities.Add(new SelectListItem { Text = "--Select City--", Value = "0" });

            if (ddlCity != null)
            {
                foreach (var x in ddlCity)
                {
                    licities.Add(new SelectListItem { Text = x.City, Value = x.Id.ToString() });
                }
            }
            return Json(new SelectList(licities, "Text", "Value"));

        }

<div class="form-group">
    @Html.LabelFor(model => model.Country, htmlAttributes: new { @class = "control-label col-md-2" })
    <div class="col-md-10">
        @Html.DropDownListFor(model => model.Country, ViewBag.state as List<SelectListItem>, new { style = "width: 200px;" })

        @Html.ValidationMessageFor(model => model.Country, "", new { @class = "text-danger" })
    </div>
</div>

<div class="form-group">
    @Html.LabelFor(model => model.City, htmlAttributes: new { @class = "control-label col-md-2" })
    <div class="col-md-10">
        @Html.DropDownListFor(model => model.City, new SelectList(string.Empty, "Value", "Text"), "--Select City--", new { style = "width:200px" })

        @Html.ValidationMessageFor(model => model.City, "", new { @class = "text-danger" })

$(document).ready(function () {

        $("#Country").change(function () {
            $("#City").empty();
            $.ajax({
                type: 'POST',
                url: '@Url.Action("GetCity")',
                dataType: 'json',
                data: { id: $("#Country").val() },
                success: function (city) {

                    $.each(city, function (i, city) {
                        $("#City").append('<option value="' + city.Value + '">'+ city.Text + '</option>');
             
                    });
                },
                error: function (ex) {
                    alert('Failed.' + ex);
                }
            });
            return false;
        })
    });