TextBox Validation

[Benniit]

Please I'm using vb.net 2013 and I have a textbox named txtRecipients

Now i want to check for the following:

1. The phone no. should always start with 233 followed by any digit other than zero like: 233201245685
2. Multiple phone numbers should be separated by a comma, like 233201245685, and the comma replaced automatically before the start of another phone number in the same format. So if two phone numbers are entered they should be like this:
233201245685,23 3547345696

I did something like this in the leave event. Is there any better way to do this as the comma is not getting replaced at a specific position. I used both the remove and replaced functions, but that did not work. Thanks in advance

  Dim str1 As String = Mid(Me.txtRecipients.Text, 1, 1) 
        Dim str2 As String = Mid(Me.txtRecipients.Text, 2, 1)
        Dim str3 As String = Mid(Me.txtRecipients.Text, 3, 1)
        Dim str4 As String = Mid(Me.txtRecipients.Text, 4, 1)
        Dim str13 As String = Mid(Me.txtRecipients.Text, 13, 1)
        If str1.Trim <> 2 Then
            Me.txtRecipients.Focus()
            MsgBox(The first digit must be 2)
            Exit Sub
        End If
        If str2.Trim <> 3 Then
            Me.txtRecipients.Focus()
            MsgBox(The second digit must be 3)
            Exit Sub
        End If
        If str3.Trim <> 3 Then
            Me.txtRecipients.Focus()
            MsgBox(The third digit must be 3)
            Exit Sub
        End If

        If str4 = 0 Then
            Me.txtRecipients.Text.Replace(0, String.Empty)
            Me.txtRecipients.Focus()
            MsgBox(Phone No. must not start with 0. Format e.g. 233243404804)
            Exit Sub
        End If

        If str13 <> "," Then
            ' Me.txtRecipients.Text.Replace(str13, ",")
            Me.txtRecipients.Focus()
            MsgBox(Phone No. must not start with 0. Format e.g. 233243404804)
            Exit Sub
        End If

[jforbes]

I currently don't have Visual Studio installed on my computer. (I know, it's a crying shame) But, I put together this VBA example of a Regular Expression that should work for your case.

Regular Expressions can be very confusing, but in a situation like this it takes care of a bunch of the IF Statements for you.

This is a piece of code that I threw into MS-Access VBA that validates the phone number to your Pattern. It does it all at once, so you loose the granularity of exactly where the validation fails, but I personally wouldn't spend the time of pointing out exactly what is wrong. I would just post the Format expected then Validate against it.

Private Sub Command0_Click()
    Dim sPhone() As String
    Dim iCount As Integer
    Dim bTest As Boolean
    
    sPhone = Split(Me.Text1.Value, ",")
    bTest = True

    'RegEx Dim Start
    Dim oRegEx As Object
    Set RegEx = CreateObject("VBScript.RegExp")
    oRegEx.Global = True
    oRegEx.Pattern = "^233[1-9](\d{8})$"
    'RegEx Dim End
    
    For iCount = 0 To UBound(sPhone)
        bTest = bTest And oRegEx.Test(sPhone(iCount))
    Next iCount
    
    MsgBox "Passes Validation: " & bTest
    
End Sub

In Visual Basic, you'll probably want to use Early Binding so instead of all the RegEx Dim Lines you can define your oRegEx variable something like:

Dim oRegEx As Regex = New Regex("^233[1-9](\d{8})$")

and put the Import at the Top of you Module:

Imports System.Text.RegularExpressions

It's been a while since I've done this, so I hope I've led you down the right path.

[Benniit]

Thanks for your urgent reply and explanation.