En un proyecto de ASP.NET 2.0 a veces puede devolver este error:
System.Web.UI.ViewStateException: Invalid viewstate. Client IP: Port: User-Agent:
System.FormatException: Invalid character in a Base-64 string. at System.Convert.FromBase64String(String s) at System.Web.UI.ObjectStateFormatter.Deserialize(String inputString) at System.Web.UI.ObjectStateFormatter.System.Web.UI.IStateFormatter.Deserialize(String serializedState) at System.Web.UI.Util.DeserializeWithAssert(IStateFormatter formatter, String serializedState) at System.Web.UI.HiddenFieldPageStatePersister.Load() --- End of inner exception stack trace ---
Podemos solucionar este error introduciendo un validationKey en el Web.Config. Introduciendo un validationKey generamos una key valida para encriptar y desencriptar el viewstate.
<;machineKey
validationKey="CDCDF7D7E7D0D1A4F33F2676B4B6FF54FA89B6CB60EA27AC4BE2DF3963
D1F64353CE611E01BF78F300B11F68F5A84E149FCEEF1F1A0AB25402C04822DE9B4B6A"
decryptionKey="9EA2F92B51CF5F5CB87F493939B66FA5E49C73F9755C3E7D"
validation="3DES" />;
Podemos generar validations keys en la página http://www.aspnetresources.com/tools/keycreator.aspx
