You can use System.Text.RegularExpressions.Regex
class to validate phone number entered in a TextBox
control in VB.NET
This is the code to validate phone number in 999-999-9999 format
Imports System.Text.RegularExpressions Public Class Form1 Private Sub ButtonValidate_Click(sender As Object, e As EventArgs) Handles ButtonValidate.Click Dim phone As New Regex("\d{3}-\d{3}-\d{4}") If (phone.IsMatch(TextBox1.Text)) Then LabelMessage.Text = "Phone Number is Valid" Else LabelMessage.Text = "Phone Number is Invalid" End If End Sub End Class
Output : Valid Number
Output : Invalid Number
You can use the RegularExpressions for other types of validation in Visual Basic.net