Visual Basic Programming Code Examples Visual Basic > API and Miscellaneous Code Examples Validating An Email Address Validating An Email Address Public Function Validate_EmailAddress(ByVal EAddress As String) As Boolean 'Dimension Variables. Const AllowChars = "1234567890ABCDEFGHIJKLMNOPQRSTUVWXYZ" + _ "abcdefghijklmnopqrstuvwxyz._-" Dim UserName As String Dim ServerName As String Dim x As Long 'Validate email address. x = InStr(1, EAddress, "@") If x = 0 Then GoTo BadAddress If InStr(x + 1, EAddress, "@") > 0 Then GoTo BadAddress UserName = Left$(EAddress, x - 1) ServerName = Right$(EAddress, Len(EAddress) - x) If Left$(UserName, 1) = "." Or Right$(UserName, 1) = "." Then GoTo BadAddress If Left$(ServerName, 1) = "." Or Right$(ServerName, 1) = "." Or _ InStr(1, ServerName, ".") = 0 Then GoTo BadAddress For i = 1 To Len(UserName) If InStr(1, AllowChars, Mid$(UserName, i, 1)) = 0 Then GoTo BadAddress Next For i = 1 To Len(ServerName) If InStr(1, AllowChars, Mid$(ServerName, i, 1)) = 0 Then GoTo BadAddress Next Validate_EmailAddress = True Exit Function BadAddress: Validate_EmailAddress = False End Function
