title: My program will not calculate totals
body: <p>I am doing a school project and I am supposed to create a database that will calculate rental equipment. It supposed to calculate the number of days and calculate a total for the entire bill. My program doesn't calculate. 
  Here is the code for the program: </p>
  
  <pre><code>Public Class VandemanForm
  
      ' Declare module level variables and constants.
  
      Const FLOOR_POLISHER_PER_DAY_Decimal As Decimal = 25.95D
      Const CARPET_STRETCHER_PER_DAY_Decimal As Decimal = 17.95D
      Const NAIL_GUN_PER_DAY_Decimal As Decimal = 11.49D
      Const AIR_COMPRESSOR_PER_DAY_Decimal As Decimal = 19.95D
  
      'This stores the price per day
  
      Private FloorPolisherPerDayDecimal As Decimal = 0D
      Private CarpetStretcherPerDayDecimal As Decimal = 0D
      Private NailGunPerDayDecimal As Decimal = 0D
      Private AirCompressorPerDayDecimal As Decimal = 0D
  
      'This stores the number of days entered
  
      Private FloorPolisherDaysDecimal As Decimal = 0D
      Private CarpetStretcherDaysDecimal As Decimal = 0D
      Private NailGunDaysDecimal As Decimal = 0D
      Private AirCompressorDaysDecimal As Decimal = 0D
  
      Private Sub CalculateButton_Click(ByVal sender As  _
          System.Object, ByVal e As System.EventArgs) _
          Handles CalculateButton.Click
  
          ' Declare procedure level variables to hold data
  
          Dim FloorPolisherTotalDecimal As Decimal = 0D
          Dim CarpetStretcherTotalDecimal As Decimal = 0D
          Dim NailGunTotalDecimal As Decimal = 0D
          Dim AirCompressorTotalDecimal As Decimal = 0D
          Dim GrandTotalDecimal As Decimal = 0D
  
          ' Check to see that data has been entered and in
          ' the correct format before calculating totals.
  
          If FirstNameTextBox.Text &lt;&gt; vbNullString And _
              LastNameTextBox.Text &lt;&gt; vbNullString Then
          Else
              MessageBox.Show("First name and last name must be entered.", _
                         "Customer name error.", MessageBoxButtons.OK, _
                         MessageBoxIcon.Error)
              FirstNameTextBox.Focus()
          End If
  
          ' Check for an entry in the equipment days text boxes and if not
          ' empty, go on to calculate
  
          Try
  
              If FloorPolisherDaysTextBox.Text &lt;&gt; vbNullString Then
                  FloorPolisherDaysDecimal = Decimal.Parse(FloorPolisherDaysTextBox.Text)
                  FloorPolisherTotalDecimal = FloorPolisherDaysDecimal * FloorPolisherPerDayDecimal
  
              End If
  
              If CarpetStretcherDaysTextBox.Text &lt;&gt; vbNullString Then
                  CarpetStretcherDaysDecimal = Decimal.Parse(CarpetStretcherDaysTextBox.Text)
                  CarpetStretcherTotalDecimal = CarpetStretcherDaysDecimal * CarpetStretcherPerDayDecimal
              End If
  
              If NailGunDaysTextBox.Text &lt;&gt; vbNullString Then
                  NailGunDaysDecimal = Decimal.Parse(NailGunDaysTextBox.Text)
                  NailGunTotalDecimal = NailGunDaysDecimal * NailGunPerDayDecimal
              End If
  
              If AirCompressorDaysTextBox.Text &lt;&gt; vbNullString Then
                  AirCompressorDaysDecimal = Decimal.Parse(AirCompressorDaysTextBox.Text)
                  AirCompressorTotalDecimal = AirCompressorDaysDecimal * AirCompressorPerDayDecimal
  
              End If
  
              GrandTotalDecimal = FloorPolisherTotalDecimal + CarpetStretcherTotalDecimal _
                  + NailGunTotalDecimal + AirCompressorTotalDecimal
  
          Catch ex As Exception
              MessageBox.Show("The days of the equipment rental must be numeric if entered.",
                               "Data Entry Error", MessageBoxButtons.OK, MessageBoxIcon.Error)
  
          End Try
  
          ' Display the results and format as currency
          FloorPolisherSubtotalTextBox.Text = FloorPolisherTotalDecimal.ToString("C")
          CarpetStretcherSubtotalTextBox.Text = CarpetStretcherTotalDecimal.ToString("C")
          NailGunSubtotalTextBox.Text = NailGunTotalDecimal.ToString("C")
          AirCompressorSubtotalTextBox.Text = AirCompressorTotalDecimal.ToString("C")
  
          GrandTotalDecimal = FloorPolisherTotalDecimal + CarpetStretcherTotalDecimal _
              + NailGunTotalDecimal + AirCompressorTotalDecimal
          TotalTextBox.Text = GrandTotalDecimal.ToString("C")
  
  
      End Sub
  
      Private Sub ExitButton_Click(ByVal sender As  _
           System.Object, ByVal e As System.EventArgs) _
           Handles ExitButton.Click
  
          Me.Close()
  
      End Sub
  
      Private Sub ClearButton_Click(ByVal sender As System.Object, _
          ByVal e As System.EventArgs) Handles ClearButton.Click
  
          ' Clear all text boxes, Return the focus to the first name field.
  
          FirstNameTextBox.Clear()
          LastNameTextBox.Clear()
          FloorPolisherDaysTextBox.Clear()
          CarpetStretcherDaysTextBox.Clear()
          NailGunDaysTextBox.Clear()
          AirCompressorDaysTextBox.Clear()
          FloorPolisherSubtotalTextBox.Clear()
          CarpetStretcherSubtotalTextBox.Clear()
          NailGunSubtotalTextBox.Clear()
          AirCompressorSubtotalTextBox.Clear()
          TotalTextBox.Clear()
  
          'Return focus to the first name textbox
          FirstNameTextBox.Focus()
  
      End Sub
  
      Private Sub OrderGroupBox_Enter(sender As System.Object, e As System.EventArgs) Handles FloorToolOrderGroupBox.Enter
  
      End Sub
  End Class
  </code></pre>