Es el código para VB para la validación del Número de Identificación Tributaria NIT de Guatemala.
Public Function ValidaNit(ByVal NIT As String) As Boolean
Dim POS As Integer
Dim Correlativo As String
Dim DigitoVerificador As String
Dim Factor As Integer
Dim Suma As Integer = 0
Dim Valor As Integer = 0
Dim X As Integer
Dim xMOD11 As Double = 0
Dim S As String = Nothing
ValidaNit = False
Try
POS = NIT.IndexOf("-")
If POS = 0 Then Exit Function
Correlativo = NIT.Substring(0, POS)
DigitoVerificador = NIT.Substring(POS + 1)
Factor = Correlativo.Length + 1
For X = 0 To (NIT.IndexOf("-") - 1)
Valor = Convert.ToInt32(NIT.Substring(X, 1))
Suma += (Valor * Factor)
Factor -= 1
Next
xMOD11 = (11 - (Suma Mod 11)) Mod 11
S = Convert.ToString(xMOD11)
If (xMOD11 = 10 And DigitoVerificador = "K") Or (S = DigitoVerificador) Then
ValidaNit = True
End If
Catch ex As Exception
MessageBox.Show(ex.Message, "Validando NIT", MessageBoxButtons.OK, _
MessageBoxIcon.Exclamation)
End Try
End Function
Esta función funciona con VB Net y cambiandole un par de cositas tambien con vb 6 y VBA.
Devuelve un falso cuando el NIT no sea correcto
