Re: Help with code for telephone validator - Visual Basic Discussion Boards

What about a masked edit control with the mask set to "999-999-9999"??

What I need to do is verify the first three 999 the first "-" second 999 second "-" and last four 9999. In the frmMain I have a textbox and a button. when the user enters a phone number 999-999-9999 the program will display one of the following messages:
"You must enter a numeric telephone number starting with the area code."
"You must enter a "-" after the area code."
"YOu must enter a "-" after the prefix."
"Invalid area code, please try again."
"Invalid prefix, please try again."
"Phone number is valid."

My problem is I have set the char to 12 in the properties for textbox1 and I need to create substrings for area code, prefix, phonenumber, and incorporate the two dashes "-" Can you help me!

The best way to validate a phone number is to use a regex. You don't need to mangle the string at all, but if you wanted to, string.split would be the easiest way here.

Christian Graus - Microsoft MVP - C++

Believe me I wish I could but the prof wants us to use VB.NET and write the program and that is why I am stuck, I cannot figure it out. Can you assist me?

Regular expressions are built into VB.NET. Are you not allowed to use those ? The other way to do it would be to use the Split method on the string that has the phone number, and use the double.TryParse method to see if they are all numbers. You can specify to not allow decimal points. The only other step is to verify the length of hte strings, and how many groups there are. A regex will do this all for you in one go. Something like \d{3}-\d{3}-\d{4} should do it, and you can change it so the - can be a space, or whatever.

Christian Graus - Microsoft MVP - C++

I tried that and it did not like it. LOL I guess VB.NET is a little more sensitive LOL.

Did you look at my code?
How can I manipulate the IsNumeric function to incorporate the dashes using the IndexOf method. See my problem is I have the keys to it but not the combination. I am just a greenie. Sorry.

12String

12String wrote:
How can I manipulate the IsNumeric function to incorporate the dashes using the IndexOf method.

That's a real hack, I would not use it. The answer though would be to use split to split into a number of substrings, by the -, and then stepping through each string.

12String wrote:
I tried that and it did not like it.

A regex ? Then you need to work with it until it does work. That was off the top of my head.

However, I just tested it, and it works fine, assuming the number is xxx-xxx-xxxx where x is a number. Did I get that wrong ? What was your code ?

Christian Graus - Microsoft MVP - C++

Here is what I have come up with so far and this doesn't quite work. What do you think. I still need to code in VB.NET so therein lays my problem. LOL

Public Class frmMain
Inherits System.Windows.Forms.Form

#Region " Windows Form Designer generated code "

Public Sub New()
MyBase.New()

'This call is required by the Windows Form Designer.
InitializeComponent()

'Add any initialization after the InitializeComponent() call

End Sub

'Form overrides dispose to clean up the component list.
Protected Overloads Overrides Sub Dispose(ByVal disposing As Boolean)
If disposing Then
If Not (components Is Nothing) Then
components.Dispose()
End If
End If
MyBase.Dispose(disposing)
End Sub

'Required by the Windows Form Designer
Private components As System.ComponentModel.IContainer

'NOTE: The following procedure is required by the Windows Form Designer
'It can be modified using the Windows Form Designer.
'Do not modify it using the code editor.
Friend WithEvents Label1 As System.Windows.Forms.Label
Friend WithEvents TextBox1 As System.Windows.Forms.TextBox
Friend WithEvents btnValPhNmb As System.Windows.Forms.Button
<system.diagnostics.debuggerstepthrough()> Private Sub InitializeComponent()
Me.Label1 = New System.Windows.Forms.Label
Me.TextBox1 = New System.Windows.Forms.TextBox
Me.btnValPhNmb = New System.Windows.Forms.Button
Me.SuspendLayout()
'
'Label1
'
Me.Label1.Font = New System.Drawing.Font("Microsoft Sans Serif", 9.75!, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
Me.Label1.Location = New System.Drawing.Point(16, 8)
Me.Label1.Name = "Label1"
Me.Label1.Size = New System.Drawing.Size(264, 24)
Me.Label1.TabIndex = 0
Me.Label1.Text = "Enter Phone Number"
Me.Label1.TextAlign = System.Drawing.ContentAlignment.MiddleCenter
'
'TextBox1
'
Me.TextBox1.Font = New System.Drawing.Font("Times New Roman", 12.0!, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
Me.TextBox1.Location = New System.Drawing.Point(80, 56)
Me.TextBox1.MaxLength = 12
Me.TextBox1.Name = "TextBox1"
Me.TextBox1.Size = New System.Drawing.Size(128, 26)
Me.TextBox1.TabIndex = 1
Me.TextBox1.Text = ""
Me.TextBox1.TextAlign = System.Windows.Forms.HorizontalAlignment.Center
'
'btnValPhNmb
'
Me.btnValPhNmb.Font = New System.Drawing.Font("Microsoft Sans Serif", 8.25!, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, CType(0, Byte))
Me.btnValPhNmb.Location = New System.Drawing.Point(88, 104)
Me.btnValPhNmb.Name = "btnValPhNmb"
Me.btnValPhNmb.Size = New System.Drawing.Size(120, 32)
Me.btnValPhNmb.TabIndex = 2
Me.btnValPhNmb.Text = "Validate Phone Number"
'
'frmMain
'
Me.AutoScaleBaseSize = New System.Drawing.Size(5, 13)
Me.BackColor = System.Drawing.SystemColors.InactiveCaptionText
Me.ClientSize = New System.Drawing.Size(292, 266)
Me.Controls.Add(Me.btnValPhNmb)
Me.Controls.Add(Me.TextBox1)
Me.Controls.Add(Me.Label1)
Me.Name = "frmMain"
Me.Text = "Phone Number Validator"
Me.ResumeLayout(False)

End Sub

#End Region

Private Sub btnValPhNmb_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnValPhNmb.Click
'Check length of input string: it must be exactly 12.
'Check Substring(3,1) and Substring(7,1), i.e. the fourth and _
'eighth character must be "-".

Dim TextBox1 As String

CheckInput() 'check to see if input is numeric and between 0 and 11

If TextBox1 = ("999" & "-" & "999" & "-" & "9999") Then
MsgBox("You have entered a correct phone number.")
ElseIf TextBox1 = "999999" & "-" & 9999 Then
MsgBox("You need to enter a " - " between the area code and prefix number.")
ElseIf TextBox1 = "999" & "-" & "9999999" Then
MsgBox("You need to enter a " - " between the prefix and phonenumber.")
End If
End Sub
Public Sub CheckInput()
If (Not IsNumeric(Me.TextBox1.Text)) Then 'checks user input for numeric and range
MsgBox("Please enter a numeric telephone number starting with the area code.")
TextBox1.Text = ""

End If
End Sub
End Class

12String wrote:
I still need to code in VB.NET so therein lays my problem

Yeah, VB sucks, but it can sure do this as easily as any other language ( and easier than vanilla C++ )

12String wrote:
If (Not IsNumeric(Me.TextBox1.Text)) Then 'checks user input for numeric and range

This plainly does not work. You should try to follow my advice, and either use a regex, or, if you must, split the string and validate it from there.

12String wrote:
If TextBox1 = ("999" & "-" & "999" & "-" & "9999") Then
MsgBox("You have entered a correct phone number.")
ElseIf TextBox1 = "999999" & "-" & 9999 Then
MsgBox("You need to enter a " - " between the area code and prefix number.")
ElseIf TextBox1 = "999" & "-" & "9999999" Then
MsgBox("You need to enter a " - " between the prefix and phonenumber.")
End If

This requires the numbers to be all nines. Your check input function should check all cases, you shouldn't be adding validation afterwards. The regex can be used to do this as well, although the split solution would make it easier to do this and give a detailed error.

Christian Graus - Microsoft MVP - C++

How do you recommend I code that? The first line then I gather is correct, yes? If TextBox1 = ("999" & "-" & "999" & "-" & "9999") Then

12String

No, that is useless. It will only accept one string. Why bother concatenating 5 values to check if the user typed 999-999-9999 ? How often would that be the number the type ?

I'm not sure in VB, but in C# it's

string [] strings = theString.Split("-");

I suspect it would be

string () strings = theString.Split("-")

but I could be wrong. Then you can check if the array has three elements, and what their lengths are. A regex will tell you if they followed the format, but not how they failed to follow it. It depends on how much detail you want in your error message.

Christian Graus - Microsoft MVP - C++

-- modified at 23:11 Thursday 27th October, 2005

All of the error messages will be handled via MsgBox message, that is why I have to code for the dashes and the numbers. Now should I code this all under the button1.clicked function or should I delcare my TextBox as a global variable then I can code everything under the button1.clicked Private Sub?

12String wrote:
All of the error messages will be handled via MsgBox message, that is why I have to code for the dashes and the numbers.

Yes, but you don't need to code it the way you have, and you shouldn't code it outside the function that validates the input.

12String wrote:
Now should I code this all under the button1.clicked function

As another function, I think so.

12String wrote:
should I delcare my TextBox as a global variable

This is always a hideous idea.

You have what you need in the checknumeric function, except what's in it is wrong. Remove the other code with the messageboxes, and instead add something which will work inside that function.

Christian Graus - Microsoft MVP - C++

So I should leave the Public Sub CheckInput() as is and delete the above msgBoxes? any suggestions on what to put in thier place LOL.

12String wrote:
any suggestions on what to put in thier place LOL.

Exactly what I've suggested already - you can split the strings by the -, and then check the rest is numbers of the right length, or use a regex.

Christian Graus - Microsoft MVP - C++

The problem is the how. I do not know how to code it. Exactly how would you code it. I cannot find any examples or close to examples in this text I have it is most frustrating.

The regex I provided will work with Regex.IsMatch ( from memory ), otherwise I've given you the syntax for the split function, and said that you need to use Double.TryParse to see if they are numnbers. I'm reluctant to do much more, that should be enough for you to find out the rest, and as this is homework, the point is learning, not just doing.

Christian Graus - Microsoft MVP - C++

Herein lies another problem, when I enter the string()strings=string.split("-") VB gives me a syntax error stating that 'String is a class type, and so is not valid. Also Name 'TheString'is not declared. UFFFFF! You see my frustration. LOL

12String wrote:
You see my frustration. LOL

Yes, the problem is that you're looking for a cut and paste solution instead of thinking about it.

string.split is my way of showing you where this function lives

myString.split obviously requires you to replace myString with the name of the variable that holds the string in your program.

Christian Graus - Microsoft MVP - C++

Christian, you deserve some sort of an award Smile | :)

You are certainly blessed with above average patience!

...Steve

I regard it as a challenge at times to lead people to their required solution. It would be easy just to give him the code, but that's not really helping him, is it ?

Having aspirations to project management, I need to work on my communication skills anyhow Smile | :)

Christian Graus - Microsoft MVP - C++

Christian Graus wrote:
It would be easy just to give him the code, but that's not really helping him, is it ?

Bravo! One of the few who thinks it's better to learn by doing (and screwing it up!) than by having it spoon fed to you!

To offer a different answer to his problem though... I've always done one of two things. Either used a Masked Edit Box or (more directly to his problem) just let the user type whatever they wanted into the box. Then in the validation or submit process, strip out everything that wasn't a number to create a string of numbers, measure the length for completeness, then put the dashes and parentheses (if needed) back in where they're supposed to go. Walla! Instant phone number that can be re-edited at any time, if needed.

RageInTheMachine9532
"...a pungent, ghastly, stinky piece of cheese!" -- The Roaming Gnome

Dave Kreskowiak wrote:
Masked Edit Box

Yeah, the easiest way to validate is to only let the user type in something that is valid Smile | :)

I can't recall if it was apparent if this was a web or windows UI though. I know it can be done with a web UI, but I tend to shun Jscript as I fear browser issues.

Christian Graus - Microsoft MVP - C++

Just a thought, what if we create a custom textbox which allow you to type only numbers and inserts "-" at proper places automaitcally

- ashish

How would we go about doing that?