I was recently putting together some proof of concept for a customer and realized that I hadn't posted one of the common Regular Expressions that I had been using.

Validating a Zip Code:

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
       
' Invalid Zip code
        'Dim strZip As String = "AB123"

        ' valid Zip Code
      
Dim strZip As String = "03110"

     
Dim regexp As New Regex(("^\d{5}$"))
    
     
If regexp.IsMatch(strZip) Then
                  
MsgBox("Zip Code")
    
Else
                 
MsgBox("No zip match")
    
End If

End Sub