Here's my code for a "find" customer button. but the only way it works is to add error handling code. I need some help with the proper way to code this.
What I need to happen is when a "wrong" ID number is entered, it shows a Message box. And if the right number is entered, then display the customers info. So far only the latter works without the error handling.
The ID number is a key column in SQL, and when a wrong number is entered it returns an error message saying the "wrong" number is a NULL value.

VB Code:
  1. Private Sub btnQVSearch_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnFind.Click

  2.         If txtNmbNumber.Text = "" Or txtNmbNumber.Text = "NMB" Then

  3.             MessageBox.Show("Please enter in a NMB Number", "Invalid Entry", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)

  4.             txtNmbNumber.Focus()

  5.             txtNmbNumber.SelectAll()

  6.             txtNmbNumber.ReadOnly = False

  7.             btnFind.Enabled = True

  8.             Exit Sub

  9.         End If

  10.         'popluate all fields that relate to id number entered

  11.         SqlDataAdapter1.Fill(DsCustomers1, "Customer")

  12.         SqlDataAdapter2.Fill(DsDrafts1, "Draft")

  13.         SqlDataAdapter3.Fill(DsPayables1, "Payables")

  14.         SqlDataAdapter4.Fill(DsAchNewbie1, "Ach")

  15.         SqlDataAdapter5.Fill(DsPayableTrans1, "Payables_Transaction")

  16.  
  17.         Dim dtCustomersUpdate As DataTable = DsCustomers1.Tables.Item("Customer")

  18.         Dim dtDraftsUpdate As DataTable = DsDrafts1.Tables.Item("Draft")

  19.         Dim dtPayablesUpdate As DataTable = DsPayables1.Tables.Item("Payables")

  20.         Dim dtAchUpdate As DataTable = DsAchNewbie1.Tables.Item("Ach")

  21.         Dim dtPayablesTransUpdate As DataTable = DsPayableTrans1.Tables.Item("Payables_Transaction")

  22.  
  23.         drCustomersUpdate = dtCustomersUpdate.Rows.Find(txtNmbNumber.Text)

  24.         drDraftsUpdate = dtDraftsUpdate.Rows.Find(txtNmbNumber.Text)

  25.         drPayablesUpdate = dtPayablesUpdate.Rows.Find(txtNmbNumber.Text)

  26.         drPayablesTransUpdate = dtPayablesTransUpdate.Rows.Find(txtNmbNumber.Text)

  27.         drAchUpdate = dtAchUpdate.Rows.Find(txtNmbNumber.Text)

  28.         Dim Msg As String

  29.         'If an error occurs, construct an error message.

  30.         On Error Resume Next

  31.         ' MessageBox.Show("Please enter in a valid NMB Number", "Invalid Entry", MessageBoxButtons.OK, MessageBoxIcon.Exclamation) ' Defer error handling.

  32.         Err.Clear()

  33.         'If the number is correct

  34.         'Customers Info Tab

  35.         If txtNmbNumber.Text = drCustomersUpdate("IDNumber") Then

  36.             ' txtNmbNumber.ReadOnly = True

  37.             btnFind.Enabled = False

  38.             ' Else

  39.             '  MessageBox.Show("Please enter in a valid NMB Number", "Invalid Entry", MessageBoxButtons.OK, MessageBoxIcon.Exclamation)

  40.             ' txtNmbNumber.Focus()

  41.             ' txtNmbNumber.SelectAll()

  42.             '  txtNmbNumber.ReadOnly = False

  43.             '  btnFind.Enabled = True

  44.         End If

  45.         If drCustomersUpdate("Agent") Is DBNull.Value Then

  46.             txtAgent.Text = ""

  47.         Else : txtAgent.Text = drCustomersUpdate("Agent")

  48.         End If

  49.         txtLastName.Text = drCustomersUpdate("LastName")

  50.         txtFirstName.Text = drCustomersUpdate("FirstName")

  51.         txtSsn1.Text = drCustomersUpdate("SSN1")

  52.         'If field is null... NOTE: fields that are required should not be null so they won't need this code

  53.         If drCustomersUpdate("LastName2") Is DBNull.Value Then

  54.             txtLastNameSpouse.Text = ""

  55.         Else : txtLastNameSpouse.Text = drCustomersUpdate("LastName2")

  56.         End If

  57.         If drCustomersUpdate("FirstName2") Is DBNull.Value Then

  58.             txtFirstNameSpouse.Text = ""

  59.         Else : txtFirstNameSpouse.Text = drCustomersUpdate("FirstName2")

  60.         End If

  61.         If drCustomersUpdate("SSN2") Is DBNull.Value Then

  62.             txt2SSN.Text = ""

  63.         Else : txt2SSN.Text = drCustomersUpdate("SSN2")

  64.         End If

  65.         If drCustomersUpdate("Address") Is DBNull.Value Then

  66.             txtAddress.Text = ""

  67.         Else : txtAddress.Text = drCustomersUpdate("Address")

  68.         End If

  69.         If drCustomersUpdate("City") Is DBNull.Value Then

  70.             txtCity.Text = ""

  71.         Else : txtCity.Text = drCustomersUpdate("City")

  72.         End If

  73.         If drCustomersUpdate("State") Is DBNull.Value Then

  74.             txtState.Text = ""

  75.         Else : txtState.Text = drCustomersUpdate("State")

  76.         End If

  77.         If drCustomersUpdate("ZipCode") Is DBNull.Value Then

  78.             txtZipCode.Text = ""

  79.         Else : txtZipCode.Text = drCustomersUpdate("ZipCode")

  80.         End If

  81.         If drCustomersUpdate("Daytime") Is DBNull.Value Then

  82.             txtDaytime.Text = ""

  83.         Else : txtDaytime.Text = drCustomersUpdate("Daytime")

  84.         End If

  85.         If drCustomersUpdate("Evening") Is DBNull.Value Then

  86.             txtEvening.Text = ""

  87.         Else : txtEvening.Text = drCustomersUpdate("Evening")

  88.         End If

  89.         If drCustomersUpdate("Notes") Is DBNull.Value Then

  90.             txtNotes.Text = ""

  91.         Else : txtNotes.Text = drCustomersUpdate("Notes")

  92.         End If

  93.         'Drafts Info Tab

  94.         txtNmbNumberDraft.Text = txtNmbNumber.Text

  95.         drDraftsUpdate("IDNumber") = txtNmbNumberDraft.Text

  96.         txtFinancialInt.Text = drDraftsUpdate("Bank")

  97.         If drDraftsUpdate("BankPhone") Is DBNull.Value Then

  98.             txtDraftPhone.Text = ""

  99.         Else : txtDraftPhone.Text = drDraftsUpdate("BankPhone")

  100.         End If

  101.         If drDraftsUpdate("RoutingNumber") Is DBNull.Value Then

  102.             txtDraftRoute.Text = ""

  103.         Else : txtDraftRoute.Text = drDraftsUpdate("RoutingNumber")

  104.         End If

  105.         txtDraftSaves.Text = drDraftsUpdate("SavingsORChecking")

  106.         'Payables Tab

  107.         '1

  108.         txtNmbNumberPayables.Text = txtNmbNumber.Text

  109.         drPayablesUpdate("IDNumber") = txtNmbNumberPayables.Text

  110.         drPayablesTransUpdate("IDNumber") = txtNmbNumberPayables.Text

  111.         txtPayable.Text = drPayablesUpdate("PayableCompany")

  112.         txtNoPayables.Text = drPayablesUpdate("NumberPayables")

  113.         txtName.Text = drPayablesUpdate("NameOnAccount")

  114.         If drPayablesUpdate("PayablesPhone") Is DBNull.Value Then

  115.             txtPayablePhone.Text = ""

  116.         Else : txtPayablePhone.Text = drPayablesUpdate("PayablesPhone")

  117.         End If

  118.         If drPayablesUpdate("PayableAddress") Is DBNull.Value Then

  119.             txtPayableAddress.Text = ""

  120.         Else : txtPayableAddress.Text = drPayablesUpdate("PayableAddress")

  121.         End If

  122.         If drPayablesTransUpdate("Starting2") Is DBNull.Value Then

  123.             txtStartDateB.Text = ""

  124.         Else : txtStartDateB.Text = drPayablesTransUpdate("Starting2")

  125.         End If

  126.         If drPayablesTransUpdate("Ending2") Is DBNull.Value Then

  127.             txtEndDateB.Text = ""

  128.         Else : txtEndDateB.Text = drPayablesTransUpdate("Ending2")

  129.         End If

  130.         If drPayablesTransUpdate("Amount3") Is DBNull.Value Then

  131.             txtPaymentC.Text = ""

  132.         Else : txtPaymentC.Text = drPayablesTransUpdate("Amount3")

  133.         End If

  134.         If drPayablesTransUpdate("Period3") Is DBNull.Value Then

  135.             txtPeriodC.Text = ""

  136.         Else : txtPeriodC.Text = drPayablesTransUpdate("Period3")

  137.         End If

  138.         If drPayablesTransUpdate("Starting3") Is DBNull.Value Then

  139.             txtStartDateC.Text = ""

  140.         Else : txtStartDateC.Text = drPayablesTransUpdate("Starting3")

  141.         End If

  142.         If drPayablesTransUpdate("Ending3") Is DBNull.Value Then

  143.             txtEndDateC.Text = ""

  144.         Else : txtEndDateC.Text = drPayablesTransUpdate("Ending3")

  145.         End If

  146.         'Ach Tab

  147.         txtNmbNumberAch.Text = txtNmbNumber.Text

  148.         drAchUpdate("IDNumber") = txtNmbNumberAch.Text

  149.         If drAchUpdate("Amount") Is DBNull.Value Then

  150.             txtAchAmount.Text = ""

  151.         Else : txtAchAmount.Text = drAchUpdate("Amount")

  152.         End If

  153.         If drAchUpdate("FeeCode") Is DBNull.Value Then

  154.             txtFeeCode.Text = ""

  155.         Else : txtFeeCode.Text = drAchUpdate("FeeCode")

  156.         End If

  157.         If drAchUpdate("Starting") Is DBNull.Value Then

  158.             txtStarting.Text = ""

  159.         Else : txtStarting.Text = drAchUpdate("Starting")

  160.         End If

  161.         If drAchUpdate("Ending") Is DBNull.Value Then

  162.             txtEnding.Text = ""

  163.         Else : txtEnding.Text = drAchUpdate("Ending")

  164.         End If

  165.         If drAchUpdate("Amount1") Is DBNull.Value Then

  166.             txtAchAmount2.Text = ""

  167.         Else : txtAchAmount2.Text = drAchUpdate("Amount1")

  168.         End If

  169.         If drAchUpdate("FeeCode1") Is DBNull.Value Then

  170.             txtFeeCode2.Text = ""

  171.         Else : txtFeeCode2.Text = drAchUpdate("FeeCode1")

  172.         End If

  173.         If drAchUpdate("Starting1") Is DBNull.Value Then

  174.             txtStarting2.Text = ""

  175.         Else : txtStarting2.Text = drAchUpdate("Starting1")

  176.         End If

  177.         If drAchUpdate("Ending1") Is DBNull.Value Then

  178.             txtEnding2.Text = ""

  179.         Else : txtEnding2.Text = drAchUpdate("Ending1")

  180.         End If

  181.         If drAchUpdate("Amount2") Is DBNull.Value Then

  182.             txtAchAmount3.Text = ""

  183.         Else : txtAchAmount3.Text = drAchUpdate("Amount2")

  184.         End If

  185.         If drAchUpdate("FeeCode2") Is DBNull.Value Then

  186.             txtFeeCode3.Text = ""

  187.         Else : txtFeeCode3.Text = drAchUpdate("FeeCode2")

  188.         End If

  189.         If drAchUpdate("Starting2") Is DBNull.Value Then

  190.             txtStarting3.Text = ""

  191.         Else : txtStarting3.Text = drAchUpdate("Starting2")

  192.         End If

  193.         If drAchUpdate("Ending2") Is DBNull.Value Then

  194.             txtEnding3.Text = ""

  195.         Else : txtEnding3.Text = drAchUpdate("Ending2")

  196.         End If

  197.     End Sub
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