clsDDLBinder

This binder synchronizes a WebForms DropDownList selection with a business-object property and performs the type conversion needed to turn selected item values into dates, numbers, booleans, enums, or strings. It uses the base binder's reflection helpers for object access while letting the page keep standard list population and selection behavior.

Purpose

• Push a bound property value into a DropDownList by selecting the matching item value.
• Convert the selected list value back into the target property type during control-to-object updates.
• Reuse the shared validation and control-formatting pipeline for single-value list selection, including BR-BIND-001.

Context

• Namespace: SAIF.Presentation.Web.Binding
• Assembly/package: SAIF.Presentation.Web.Binding.Infragistics103 (embedded/bundled as source, not independently packaged)

Public members

Member	Signature	Purpose
BindProperty	Property BindProperty As String	Names the business-object property that receives or provides the selected list value.
BindSource	Property BindSource As Object	Holds the business object whose property is synchronized with the list selection.
DropDownList	Property DropDownList As DropDownList	Attaches the concrete list control and registers it with the base binder pipeline.
TargetType	Property TargetType As ObjectDataType	Selects the conversion path used when reading from or writing to the selected item value.
Init()	Overrides Sub Init()	Hooks SelectedIndexChanged when event-driven write-back is enabled for the current bind direction.
ObjectToControl()	Overrides Function ObjectToControl() As Boolean	Finds the list item whose value matches the bound property and makes it the active selection.
## Inherited public members
Member	Signature	Purpose
---	---	---
ContainsError	ReadOnly Property ContainsError As Boolean	Set by GetErrors()/validation processing; when true, Validate()/RefreshValidation() counts this binder toward the overall invalid result and its control receives error-state CSS via SetControlFormat().
IsDualBinding	ReadOnly Property IsDualBinding As Boolean	When true, ObjectToControl()/ControlToObject() read and write the display object/property while GetErrors() checks a separate validation object/property, as configured by AddDualBinder().
ControlPadding	Property ControlPadding As PadArgs	When UsePadding is enabled, pads or trims the value written to the control during ObjectToControl(), so fixed-width display formatting is applied without changing the underlying object value.
ObjectPadding	Property ObjectPadding As PadArgs	When UsePadding is enabled, pads or strips padding from the value written back to the bound property during ControlToObject(), so stored data is not polluted with display-only padding characters.
UsePadding	Property UsePadding As Boolean	Enables the ControlPadding/ObjectPadding transforms during ObjectToControl()/ControlToObject(); when false, values pass through unpadded regardless of the padding arguments configured.
UseEvents	Property UseEvents As Boolean	When true, Init() wires the control's native change event so a user edit immediately calls ControlToObject() instead of waiting for an explicit BindToObject()/Validate() call.
ControlErrors	ReadOnly Property ControlErrors As ArrayList	Holds the error text GetErrors() collects from the bound object's IDataErrorInfo implementation; Validate() aggregates these strings into the consolidated ErrorLabel/SAIFMessage output.
BindType	Property BindType As BindTypes	Determines which of ObjectToControl()/ControlToObject() actually run during DataBind()/BindToObject(), controlling whether this binder is push-only, pull-only, both, or validation-only.
FormControl	Overridable Property FormControl As WebControl	Setting this property runs ProcessControl, which applies binder-specific control setup (event wiring readiness, CSS baseline) before the control participates in binding and validation passes.
FormControlID	Overridable ReadOnly Property FormControlID As String	Supplied to Update() and error-focus logic to locate this binder's control instance on the page without holding a direct control reference.
Init()	MustOverride Sub Init()	Called once during AddBinder() registration; each concrete binder overrides this to hook the native control event needed for event-driven ControlToObject() and to perform any control-specific setup.
ObjectToControl()	MustOverride Function ObjectToControl() As Boolean	Invoked by DataBind() for binders configured as ObjectToControl/TwoWay; each concrete binder overrides this to translate the bound property's value into the control-specific display state.
ControlToObject()	Protected Friend MustOverride Sub ControlToObject()	Invoked by BindToObject() for binders configured as ControlToObject/TwoWay; each concrete binder overrides this to convert the control's current value back into the bound property's type.
SetControlFormat(inValid As Boolean)	Protected Friend Overridable Sub SetControlFormat(inValid As Boolean)	Called by Validate()/RefreshValidation() after error collection; sets the control's CssClass to the valid/error color per BR-BIND-001, BR-BIND-002, and BR-BIND-003, giving the reader a visual cue of validation state.
GetErrors()	Protected Friend Overridable Sub GetErrors()	Reads the bound object's IDataErrorInfo.Item(property) during Validate()/RefreshValidation() and appends any non-empty message to ControlErrors, driving both ContainsError and the consolidated error display.
GetObjectValueAsString(inBizObject, inPropertyName)	Function GetObjectValueAsString(inBizObject As Object, inPropertyName As String) As String	Used by ObjectToControl() to fetch the bound property's current value as display-ready text, applying ObjectPadding/ControlPadding first when UsePadding is enabled.
GetObjectValue(inBizObject, inPropertyName)	Function GetObjectValue(inBizObject As Object, inPropertyName As String) As Object	Used by ObjectToControl() and type-sensitive binders to fetch the bound property's value in its native CLR type, before any control-specific conversion or formatting.
SetObjectValueAsString(inBizObject, inPropertyName, inValue)	Protected Function SetObjectValueAsString(inBizObject As Object, inPropertyName As String, inValue As String) As Boolean	Used by ControlToObject() to write a control-derived string back onto the bound property, applying padding/trim rules first when UsePadding is enabled, so the object receives a correctly formatted value.
SetObjectValue(inBizObject, inPropertyName, inValue)	Protected Function SetObjectValue(inBizObject As Object, inPropertyName As String, inValue As Object) As Boolean	Used by ControlToObject() to write a converted, strongly typed value back onto the bound property, bypassing string formatting for binders that perform their own type conversion.
ValidationKey	Friend Overridable ReadOnly Property ValidationKey As String	Computed by AddBinder() to key the bound object into m_ValidationObjects per BR-BIND-006, ensuring repeated Validate() passes re-check the correct distinct object.
IsSAIFFrameWorkObject	Friend Overridable ReadOnly Property IsSAIFFrameWorkObject(Optional inObj As Object) As Boolean	Detects SAIF framework objects by walking the CLR base-type chain for clsBusinessBase/clsBusinessCollectionBase.
## Behavioral notes
- ObjectToControl() uses Items.FindByValue(value) and clears any previous selection before selecting the matching item.
- ControlToObject() converts SelectedItem.Value according to TargetType, including Enum.Parse(enumType, value) for enum-backed properties.
- Inherited control formatting applies the base CSS behavior, including BR-BIND-001, because this binder does not override SetControlFormat().

Constraints and usage notes

• The control must already contain items whose Value entries match the bound property values.
• TargetType must align with both the selected value text and the destination property type to avoid conversion failures.
• Enum write-back uses the runtime type of the current property value, so the bound property must already be initialized to the correct enum type.

Sources

• SAIF.Presentation.Web.Binding.Infragistics103\ASPControls\clsDDLBinder.vb
• SAIF.Presentation.Web.Binding.Infragistics103\clsObjectBinderbase.vb