ASP.NET

Protected Sub WriteToExcelFile(dt As DataTable)
    'This method exports the resulting query datatable to an instance of Excel using StringWriter
    If Not dt Is Nothing Then
        Dim sw As New StringWriter()
        'Loop through the column names and output those first
        For Each datacol As DataColumn In dt.Columns
            sw.Write(datacol.ColumnName + vbTab)
        Next
        Dim row As DataRow
        'Loop through the datatable's rows
        For Each row In dt.Rows
            'Newline between the previous row and the next row
            sw.Write(vbNewLine)
            Dim column As New DataColumn()
            'Loop through each column and write the cell the the stringwriter
            For Each column In dt.Columns
                'If the cell isn't empty write it, else write an empty cell
                If Not row(column.ColumnName) Is Nothing Then
					sw.Write("=""" & row(column).ToString().Trim() & """" & vbTab)
                    Else
                        sw.Write(String.Empty + vbTab)
                    End If
                Next column
            Next row
            'create an instance of Excel and write the data
            Response.Clear()
            Response.ContentType = "application/vnd.ms-excel"
            Response.AddHeader("Content-Disposition", "attachment;filename=GridViewExport.xls")
            Response.Output.Write(sw.ToString())
            Response.Flush()
            System.Web.HttpContext.Current.Response.Flush()
            System.Web.HttpContext.Current.Response.SuppressContent = True
            System.Web.HttpContext.Current.ApplicationInstance.CompleteRequest()
        End If
End Sub

ViewData["sentResponseType"] = new SelectList(_context.EntityType.Where(g => g.EntityKey == "sentResponseType")
        .Include(x => x.ApiApplicantHistoryLastReqStatusNavigation).ToList(), "ID", "name");

ViewBag.sentResponseType

public async Task<IActionResult> Edit(int id, ApplicantViewModel applicant)
    {
        var formerApplicantType = await _context.Applicant
            .Include(a => a.ApplicantTypeNavigation)
            .FirstOrDefaultAsync(m => m.ApplicantId == id);

        if (id != applicant.applicantvm.ApplicantId)
        {
            return NotFound();
        }

        if (ModelState.IsValid)
        {
            try
            {
                if (applicant.applicantvm.ApplicantType == 1)
                {
                    var UpdQuery = from a in _context.Applicant
                                   join p in _context.PersonApplicant on a.ApplicantId
                                   equals p.ApplicantId
                                   where applicant.applicantvm.ApplicantId == a.ApplicantId && applicant.applicantvm.ApplicantType == a.ApplicantType
                                   select new { a, p };

                    if (formerApplicantType.ApplicantType == 2)
                    {
                        Debug.WriteLine("opposite applicantType");

                        var legalApplicantForDelete = await _context.LegalApplicant.FindAsync(id);
                        _context.LegalApplicant.Remove(legalApplicantForDelete);

                        //?????
                        var pa = new PersonApplicant()
                        {
                            BirthCertificateNo = applicant.personapplicantvm.BirthCertificateNo,
                            IssuePlace = applicant.personapplicantvm.IssuePlace,
                            NationalCode = applicant.personapplicantvm.NationalCode,
                            Username = applicant.personapplicantvm.Username,
                            Applicant = applicant.applicantvm
                        };
                        using (var context = new CSSDDashboardContext())
                        {
                            context.PersonApplicant.Add(pa);
                            context.SaveChanges();
                        }
                    }
                    else
                    {


                        //----------------------------------------------
                        foreach (var x in UpdQuery.ToList())
                        {
                            x.a.ApplicantType = applicant.applicantvm.ApplicantType;
                            x.a.Address = applicant.applicantvm.Address;
                            x.a.Description = applicant.applicantvm.Description;
                            x.a.Name = applicant.applicantvm.Name;
                            x.p.BirthCertificateNo = applicant.personapplicantvm.BirthCertificateNo;
                            x.p.NationalCode = applicant.personapplicantvm.NationalCode;
                            x.p.IssuePlace = applicant.personapplicantvm.IssuePlace;
                            x.p.Username = applicant.personapplicantvm.Username;

                        }
                    }

                await _context.SaveChangesAsync();

            }
            catch (DbUpdateConcurrencyException)
            {
                if (!ApplicantExists(applicant.applicantvm.ApplicantId))
                {
                    return NotFound();
                }
                else
                {
                    throw;
                }
            }
            return RedirectToAction(nameof(Index));
        }
        ViewData["ApplicantType"] = new SelectList(_context.EntityType, "Id", "Id", applicant.applicantvm.ApplicantType);
        return View(applicant);
    }

Protected Sub DDLbuilding_SelectedIndexChanged(sender As Object, e As EventArgs) Handles DDLbuilding.SelectedIndexChanged
        'Create DataTable
        Dim dtRooms As New DataTable() ' - Room Numbers
        dtRooms.Columns.Add("Room", Type.GetType("System.String"))

        'Get Buildings for this campus
        RoomTable = RoomAdapter.GetRooms(DDLbuilding.SelectedValue)

        'Fill DataTable
        For Each RoomRow In RoomTable
            dtRooms.Rows.Add()
            dtRooms.Rows(dtRooms.Rows.Count - 1)("Room") = RoomRow.Room
        Next

        'bind DDLroom to datatable
        DDLroom.DataSource = dtRooms
        DDLroom.DataBind()
    End Sub

Protected Sub cbEQName_SelectedIndexChanged(sender As Object, e As EventArgs)

     'Get row index of selected comboBox
     Dim gvRow As GridViewRow = CType(CType(sender, Control).Parent.Parent, GridViewRow)
     Dim index As Integer = gvRow.RowIndex

     'Get selected value of selected comboBox
     EQname = TryCast(GVnewEquipment.Rows(index).FindControl("cbEQname"), AjaxControlToolkit.ComboBox).Text

     'Get new values of next comboBox from selected value of selected comboBox
     EquipmentTable = EquipmentAdapter.GetMfg(EQname)

     'Create DataTable
     Dim dtMfgs As New DataTable() ' - mfgs that are used by Equiptment name
     dtMfgs.Columns.Add("mfg", Type.GetType("System.String"))

     'Fill DataTable
     For Each EquipmentRow In EquipmentTable
         dtMfgs.Rows.Add()
         dtMfgs.Rows(dtMfgs.Rows.Count - 1)("mfg") = EquipmentRow.mfg
     Next

     'create ComboBox which will represent GVnewQuipment cbMfg comboBox
     Dim CB = DirectCast(GVnewEquipment.Rows(index).FindControl("cbMfg"), AjaxControlToolkit.ComboBox)

     'bind cbMfg to datatable
     CB.DataSource = dtMfgs
     CB.DataBind()

 End Sub

Hi. I'm implementing asp.net core project. In my controller class I have a query like below that joins two tables.

          var UpdQuery = from a in _context.Applicant
                                       join p in  _context.PersonApplicant on a.ApplicantId
                                       equals p.ApplicantId
                                       where    applicant.applicantvm.ApplicantId == a.ApplicantId // && applicant.applicantvm.ApplicantType == a.ApplicantType
                                       select new { a, p };
                        
I want to get the value of one of Updquery's fields which is called ApplicantType and it is of type int. For doing this, I wrote a query like below to get that value. However it doesn't give me a correct value.

                        var formerApplicantType = UpdQuery.Select(u => u.a.ApplicantType).SingleOrDefault();
                        Debug.WriteLine("formerApplicantType:" + int.Parse(formerApplicantType.ToString()));

I appreciate if any one tells me where do I make a mistake?

Protected Sub txtEmpID_TextChanged(sender As Object, e As EventArgs) Handles txtEmpID.TextChanged
      If String.IsNullOrEmpty(txtEmpID.Text) Then
          checkusername.Visible = False
          Return
      End If

      ' Clear the controls:
      'txtEmpID.Text = String.Empty
      txteName.Text = String.Empty
      txttitle.Text = String.Empty
      txtemail.Text = String.Empty
      lblStatus.Text = String.Empty

      Gridview1.DataSource = Nothing
      Gridview1.DataBind()
      grvspouse.DataSource = Nothing
      grvspouse.DataBind()
      grvDiv.DataSource = Nothing
      grvDiv.DataBind()
      grvReim.DataSource = Nothing
      grvReim.DataBind()
      grvHon.DataSource = Nothing
      grvHon.DataBind()
      grvGift.DataSource = Nothing
      grvGift.DataBind()
      grvOrg.DataSource = Nothing
      grvOrg.DataBind()
      grvCred.DataSource = Nothing
      grvCred.DataBind()

      checkusername.Visible = True
      dprocessed.Visible = True
      lblStatus.ForeColor = System.Drawing.Color.Red

      Using Conn As New SqlConnection(ConfigurationManager.ConnectionStrings("constr").ConnectionString)
          Using cmd As New SqlCommand("ValidateEmpID", Conn)
              cmd.CommandType = CommandType.StoredProcedure
              cmd.Parameters.AddWithValue("@empID", txtEmpID.Text)

              Conn.Open()
              Using dr As SqlDataReader = cmd.ExecuteReader(CommandBehavior.CloseConnection)
                  If Not dr.Read() Then
                      imgstatus.ImageUrl = "images/Icon_Available.gif"
                      lblStatus.Text = "This must be the first time you are completing this form. Proceed to complete entire form. If you feel there is a mistake, please contact the office"
                      txteName.Enabled = True
                      txttitle.Enabled = True
                      txtemail.Enabled = True
                      txtEmpID.Enabled = True
                      GridPanels.Enabled = True
                      btnNext.Enabled = True
                      Return
                  End If

                  imgstatus.ImageUrl = "images/NotAvailable.jpg"
                  txteName.Text = dr("employeeName").ToString()
                  txttitle.Text = dr("empTitle").ToString()
                  txtemail.Text = dr("email").ToString()
                  txtEmpID.Text = dr("empID").ToString()

                  If dr("previousYear").ToString() = "1" Then
                      lblStatus.Text = "Please verify your information for accuracy. Then complete rest of the form."
                      txteName.Enabled = True
                      txttitle.Enabled = True
                      txtemail.Enabled = True
                      txtEmpID.Enabled = True
                      GridPanels.Enabled = True
                      btnNext.Enabled = True
                      fillSourceRecords()

                  ElseIf dr("thisYear").ToString() = "1" Then
                      lblStatus.Text = "You have already completed this form. Please close the form. If you feel there is a mistake, please contact the office"
                      txteName.Enabled = False
                      txttitle.Enabled = False
                      txtemail.Enabled = False
                      txtEmpID.Enabled = False
                      GridPanels.Enabled = False
                      btnNext.Enabled = False

                  Else
                      lblStatus.Text = "No entries this year, nor the previous year. Please complete the form. If you feel this is a mistake, please contact Clerk to the CEO and BOC at 404-371-3224"
                      txteName.Enabled = False
                      txttitle.Enabled = False
                      txtemail.Enabled = False
                      txtEmpID.Enabled = False
                      GridPanels.Enabled = False
                      btnNext.Enabled = False
                  End If
              End Using
          End Using
      End Using
  End Sub

  Private Sub fillSourceRecords()
      Dim conn_str As String = ConfigurationManager.ConnectionStrings("constr").ConnectionString

      Using conn As SqlConnection = New SqlConnection(ConfigurationManager.ConnectionStrings("constr").ConnectionString)
          conn.Open()
          Using sourcecmd As SqlCommand = New SqlCommand()
              sourcecmd.CommandText = "uspGetAllRecs"
              sourcecmd.CommandType = CommandType.StoredProcedure
              sourcecmd.Parameters.AddWithValue("@empID", txtEmpID.Text.Trim())
              sourcecmd.Connection = conn
              Using ad As SqlDataAdapter = New SqlDataAdapter(sourcecmd)
                  Dim ds As DataSet = New DataSet()
                  ad.Fill(ds)
                  Gridview1.DataSource = ds
                  Gridview1.DataBind()
                  grvspouse.DataSource = ds
                  grvspouse.DataBind()
                  grvDiv.DataSource = ds
                  grvDiv.DataBind()
                  grvReim.DataSource = ds
                  grvReim.DataBind()
                  grvHon.DataSource = ds
                  grvHon.DataBind()
                  grvGift.DataSource = ds
                  grvGift.DataBind()
                  grvOrg.DataSource = ds
                  grvOrg.DataBind()
                  grvCred.DataSource = ds
                  grvCred.DataBind()
              End Using
          End Using
      End Using

  End Sub

public partial class InvalidCaseUserControl : System.Web.UI.UserControl
{
    private int _batchNumber;
    private System.ComponentModel.IContainer components = null;
    /// <summary>
    /// Clean up any resources being used.
    /// </summary>
    /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
    protected override void Dispose(bool disposing)//Getting 'InvalidCaseUserControl.Dispose(bool)':no suitable method found to override
    {
        if (disposing && (components != null))
        {
            components.Dispose();
        }
        base.Disposed(disposing);
    }
}