Question

i tried something like this, it insert into the database even thought nric is wrong.
So i want it to stop inserting the data into the database when the nric validation is wrong, however from what i do, the result is it still insert the name in….so where should change to allow it stop inserting until user change the value then can continue insert???

Protected Sub btnSubmit_Click(sender As Object, e As EventArgs) Handles btnSubmit.Click
        register()

    End Sub   

 Protected Sub nricValidate()
        Dim strRegex As String = "^([sS]\d{7}[a-zA-Z])$"
        Dim myRegex As Regex = New Regex(strRegex)
        Dim strNr As String = txtNRIC.Text
        Dim nric As String = txtNRIC.Text
        If String.IsNullOrEmpty(txtNRIC.Text) Then

        ElseIf myRegex.IsMatch(strNr) Then
            Dim nricArray() As Char = nric.ToArray
            Dim sum As Integer = 0
            Dim num As Integer = 0
            Dim result As Integer = 0
            Dim numbers As Char
            Dim no As String = ""

            Dim i As Integer = 0
            Do While (i < nricArray.Length)
                If (i = 1) Then
                    num = 0
                    numbers = nricArray(i)
                    no = numbers.ToString
                    num = Convert.ToInt32(no)
                    num = (num * 2)
                    nricArray(i) = Convert.ToChar(num)
                ElseIf (i = 2) Then
                    num = 0
                    numbers = nricArray(i)
                    no = numbers.ToString
                    num = Convert.ToInt32(no)
                    num = (num * 7)
                    nricArray(i) = Convert.ToChar(num)
                ElseIf (i = 3) Then
                    num = 0
                    numbers = nricArray(i)
                    no = numbers.ToString
                    num = Convert.ToInt32(no)
                    num = (num * 6)
                    nricArray(i) = Convert.ToChar(num)
                ElseIf (i = 4) Then
                    num = 0
                    numbers = nricArray(i)
                    no = numbers.ToString
                    num = Convert.ToInt32(no)
                    num = (num * 5)
                    nricArray(i) = Convert.ToChar(num)
                ElseIf (i = 5) Then
                    num = 0
                    numbers = nricArray(i)
                    no = numbers.ToString
                    num = Convert.ToInt32(no)
                    num = (num * 4)
                    nricArray(i) = Convert.ToChar(num)
                ElseIf (i = 6) Then
                    num = 0
                    numbers = nricArray(i)
                    no = numbers.ToString
                    num = Convert.ToInt32(no)
                    num = (num * 3)
                    nricArray(i) = Convert.ToChar(num)
                ElseIf (i = 7) Then
                    num = 0
                    numbers = nricArray(i)
                    no = numbers.ToString
                    num = Convert.ToInt32(no)
                    num = (num * 2)
                    nricArray(i) = Convert.ToChar(num)
                End If
                i = (i + 1)
            Loop
            i = 0
            Do While (i < nricArray.Length)
                If ((i > 0) _
                            AndAlso (i < 8)) Then
                    numbers = nricArray(i)
                    num = Convert.ToInt32(numbers)
                    sum = (sum + num)
                End If
                i = (i + 1)
            Loop
            result = (sum Mod 11)
            If (result = 10) Then
                If (nricArray(8) = Microsoft.VisualBasic.ChrW(65)) Then

                Else

                    txtNRIC.Focus()
                    ResultLabel.Text = "last alphabet should be 'A' Nric Error"
                End If
            ElseIf (result = 9) Then
                If (nricArray(8) = Microsoft.VisualBasic.ChrW(66)) Then

                Else

                    txtNRIC.Focus()
                    ResultLabel.Text = "last alphabet should be 'B' Nric Error"
                End If
            ElseIf (result = 8) Then
                If (nricArray(8) = Microsoft.VisualBasic.ChrW(67)) Then

                Else

                    txtNRIC.Focus()
                    ResultLabel.Text = "last alphabet should be 'C'Nric Error"
                End If
            ElseIf (result = 7) Then
                If (nricArray(8) = Microsoft.VisualBasic.ChrW(68)) Then

                Else

                    txtNRIC.Focus()
                    ResultLabel.Text = "last alphabet should be 'D'Nric Error"
                End If
            ElseIf (result = 6) Then
                If (nricArray(8) = Microsoft.VisualBasic.ChrW(69)) Then

                Else

                    txtNRIC.Focus()
                    ResultLabel.Text = "last alphabet should be 'E'Nric Error"
                End If
            ElseIf (result = 5) Then
                If (nricArray(8) = Microsoft.VisualBasic.ChrW(70)) Then

                Else

                    txtNRIC.Focus()
                    ResultLabel.Text = "last alphabet should be 'F'Nric Error"

                End If
            ElseIf (result = 4) Then
                If (nricArray(8) = Microsoft.VisualBasic.ChrW(71)) Then

                Else

                    txtNRIC.Focus()
                    ResultLabel.Text = "last alphabet should be 'G'Nric Error"
                End If
            ElseIf (result = 3) Then
                If (nricArray(8) = Microsoft.VisualBasic.ChrW(72)) Then

                Else

                    txtNRIC.Focus()
                    ResultLabel.Text = "last alphabet should be 'H'Nric Error"
                End If
            ElseIf (result = 2) Then
                If (nricArray(8) = Microsoft.VisualBasic.ChrW(73)) Then

                Else

                    txtNRIC.Focus()
                    ResultLabel.Text = "last alphabet should be 'I'Nric Error"
                End If
            ElseIf (result = 1) Then
                If (nricArray(8) = Microsoft.VisualBasic.ChrW(90)) Then

                Else

                    txtNRIC.Focus()
                    ResultLabel.Text = "last alphabet should be 'Z'Nric Error"
                End If
            ElseIf (result = 0) Then
                If (nricArray(8) = Microsoft.VisualBasic.ChrW(74)) Then

                Else

                    txtNRIC.Focus()
                    ResultLabel.Text = "last alphabet should be 'J'Nric Error"
                End If
            End If



            Return
        Else
            ResultLabel.Text = "The NRIC is incorrect!"
            txtNRIC.Text = String.Empty
            txtNRIC.Focus()
        End If


    End Sub

Protected Sub register()

        Dim myConn As New SqlConnection
        Dim myCmd As New SqlCommand
        myConn.ConnectionString = ConfigurationManager.ConnectionStrings("Company").ConnectionString
        Dim cmd As String
        cmd = "Insert into Customer values (@fullName,  @nric) "
        myCmd.CommandText = cmd
        myCmd.CommandType = CommandType.Text

        nricValidate()

        myCmd.Parameters.Add(New SqlParameter("@fullName", txtName.Text))

        myCmd.Parameters.Add(New SqlParameter("@nric", txtNRIC.Text))


        myCmd.Connection = myConn
        myConn.Open()
        myCmd.ExecuteNonQuery()
        myCmd.Dispose()
        myConn.Dispose()




    End Sub

Answer 1

That big loop is entirely unnecessary. There’s so much to fix here that I’ll do a big rewrite. I turned 216 lines into 41, no problem. It could most likely be made much better, too.

Protected Sub btnSubmit_Click(sender As Object, e As EventArgs) Handles btnSubmit.Click
    If nricValidate() Then
        Using myConn As New SqlConnection(ConfigurationManager.ConnectionStrings("Company").ConnectionString),
              myCmd As SqlCommand = myConn.CreateCommand()
            myCmd.CommandText = "INSERT INTO Customer VALUES(@fullName, @nric)"
            myCmd.CommandType = CommandType.Text

            myCmd.Parameters.Add(New SqlParameter("@fullName", txtName.Text))
            myCmd.Parameters.Add(New SqlParameter("@nric", txtNRIC.Text))

            myConn.Open()
            myCmd.ExecuteNonQuery()
        End Using
    End If
End Sub

Protected Function nricValidate() As Boolean
    Dim myRegex As New Regex("^([sS]\d{7}[a-zA-Z])$")

    If Not String.IsNullOrEmpty(txtNRIC.Text) AndAlso myRegex.IsMatch(txtNRIC.Text) Then
        Dim nricArray(txtNRIC.Text.Length - 1) As Integer
        Dim sum As Integer = 0

        For i As Integer = 1 To 7
            sum += Integer.Parse(txtNRIC.Text.Substring(i, 1)) * If(i = 1, 2, 9 - i)
        Next

        If nricArray(8) <> 75 - sum Mod 11 Then
            txtNRIC.Focus()
            ResultLabel.Text = "The last value should be " & (75 - sum Mod 11).ToString() & ": NRIC Error"
            Return False
        End If

        Return True
    Else
        ResultLabel.Text = "The NRIC is incorrect!"
        txtNRIC.Text = String.Empty
        txtNRIC.Focus()
    End If

    Return False
End Function

Your actual answer is – you need to turn nricValidate into a Function, return a success value, and check for success before inserting into the database. But the rest of your code could be heavily optimized too, as you can see.

I do apologize in advance, but that is the worst code I’ve ever seen in my entire life. Please read up on how to program in general.