Validadar un texbox para ingresar solo numeros o solamente letras

[Mickel]

en VB.NET:

Public Shared Function SoloNumeros(ByVal KCode As Int16) As Boolean
If (KCode >= 48 And KCode <= 57) Or KCode = 8 Then
Return False
Else
Return True
End If
End Function

Public Shared Function SoloDecimales(ByVal KCode As Int16) As Boolean
If (KCode >= 48 And KCode <= 57) Or KCode = 8 Or KCode = 45 Or KCode = 46 Then
Return False
Else
Return True
End If
End Function


Public Shared Function SoloLetras(ByVal KCode As Int16) As Boolean
If (KCode >= 65 And KCode <= 90) or (KCode >= 97 And KCode <= 122) Or KCode = 8 Then
Return False
Else
Return True
End If
End Function

y luego pones en el Keypress...
e.Handled = SoloLetras(System.Convert.ToInt16(Asc(e.KeyChar)))
o lo que necesites...