clsModelBase¶

clsModelBase is the screen model base class every SAIF screen's concrete model derives from. It holds the screen's clsContext and user clsPreferences, defines the validate-then-write contract (ValidateData → WriteData, exposed publicly as Write) that Validate and write the model documents, performs one-time initialization and preference loading through Pre_Init (called from clsControllerBase.Initialize), and supplies a small set of protected string/date validation helpers reused by derived screens' own ValidateData implementations.

Purpose¶

Gates every model write behind the derived screen's own validation, so WriteData is only ever called when ValidateData returns True (BR-MVC-029).
Performs one-time model initialization and user-preference loading on first use per instance, via Pre_Init (BR-MVC-016).
Carries the screen's clsContext, giving every model access to the established security principal, cross-application context values, and well-known context keys (claimId, policyNum, etc.).
Provides reusable string/number/date validation predicates so derived ValidateData implementations do not each reimplement basic input checks.

Context¶

Namespace: SAIF.Presentation.Web.MVC*
Assembly/package: SAIF.Presentation.Web.MVC

Public members¶

Member	Signature	Purpose
`New`	`Public Sub New()`	Constructs the model with a fresh `clsContext` instance
`Context`	`Public Property Context() As clsContext`	The screen's context bag — security principal, well-known claim/policy fields, and cross-application context values
`LastError`	`Public Property LastError() As String`	Free-form error text a derived model can set for the calling controller/screen to surface
`Preferences`	`Public ReadOnly Property Preferences() As clsPreferences`	The user's preferences, loaded once by `Pre_Init` for the model's application/user pair
`SecurityPrincipal`	`Public Property SecurityPrincipal() As clsSecurityPrincipal` (marked `Obsolete`, favoring `Context.SecurityPrincipal`)	Legacy pass-through to `Context.SecurityPrincipal`, retained for backward compatibility
`Write`	`Protected Friend Function Write() As Boolean`	Calls the derived `ValidateData()`; only when it returns `True` does it call `WriteData()` and return its result, otherwise returns `False` without writing (BR-MVC-029)
`ValidateData`	`Protected Friend MustOverride Function ValidateData() As Boolean`	Derived-class hook that validates the model's current state before a write is attempted
`WriteData`	`Protected Friend MustOverride Function WriteData() As Boolean`	Derived-class hook that persists the model's current state; only invoked after `ValidateData` succeeds
`Initialize`	`Protected Friend Overridable Sub Initialize()`	Derived-class hook called exactly once per model instance, from `Pre_Init`; default implementation is a no-op
`UnInitialize`	`Protected Friend Overridable Sub UnInitialize()`	Derived-class hook for model teardown; default implementation is a no-op
`IsValidString`	`Protected Function IsValidString(ByVal Value As String) As Boolean`	`True` unless the value is `Nothing` or, after trimming, empty
`IsValidNumber`	`Protected Function IsValidNumber(ByVal Value As String) As Boolean`	`True` when the value is a valid non-empty string and `IsNumeric`
`IsValidDate`	`Protected Function IsValidDate(ByVal Value As String) As Boolean`	`True` when the value is a valid non-empty string and `IsDate`
`IsValidFutureDate` (string)	`Protected Function IsValidFutureDate(ByVal Value As String) As Boolean`	`True` when the value is a valid date string strictly later than today (compared by short date)
`IsValidFutureDate` (date)	`Protected Function IsValidFutureDate(ByVal Value As Date) As Boolean`	`True` when the date value is strictly later than today (compared by short date)

Behavioral notes¶

Pre_Init (Friend, called by clsControllerBase.Initialize as part of Initialize a request) is idempotent per instance: it checks an internal m_Inited flag before calling Initialize() and constructing clsPreferences, so it only runs once even if invoked multiple times against the same model instance (BR-MVC-016).
Preferences is constructed with Context.SecurityPrincipal.UserName().ToString and the application name, so it is only safely accessible after SecurityPrincipal has been established (i.e., after Pre_Init has run following a successful SecurityCheck).

Constraints and usage notes¶

clsModelBase is MustInherit — every screen supplies its own concrete model subclass and overrides ValidateData and WriteData (both MustOverride).
SecurityPrincipal is marked Obsolete; new code should read/write Context.SecurityPrincipal directly.

Note: Statements marked with * were inferred from code structure, naming conventions, or contextual evidence where direct confirmation was not available in source artifacts.

Sources¶

SAIF.Presentation.Web.MVC/clsModelBase.vb