public static int? GetMaxLength(this EntityObject entite,string nomPropriete)
    {
        int? result = null;
        using (XEntities contexte = XEntities.GetCurrentContext())
        {
            var queryResult = from Meta in contexte.MetadataWorkspace.GetItems(DataSpace.CSpace)
                               .Where(m => m.BuiltInTypeKind == BuiltInTypeKind.EntityType)
                              from p in (Meta as EntityType).Properties
                                 .Where(p => p.DeclaringType.Name == entite.GetType().Name
                                     && p.Name == nomPropriete
                                     && p.TypeUsage.EdmType.Name == "String")
                              select p.TypeUsage.Facets["MaxLength"].Value;
            if (queryResult.Count() > 0)
            {
                result = Convert.ToInt32(queryResult.First());
            }
        }
        return result;
    }