clsDropDownController¶

clsDropDownController is a non-rendering System.Web.UI.Control subclass that cascades two UltraWebGrid columns' drop-down value lists: it binds a parent column and a child column to consumer-supplied data sources, and generates the client-side JavaScript that filters the child column's options to only those associated with the parent column's currently selected value. It is declared on a page alongside the grid it targets and is driven entirely by the standard DataBind lifecycle call; it has no rendering output of its own and no other type in this library calls it.

Purpose¶

Bind a parent (Column1) and child (Column2) UltraWebGrid column's value lists from consumer-supplied IEnumerable sources (BR-CTL-004).
Project both data sources into flattened ListItem lookup lists, skipping members that cannot be converted to String (BR-CTL-005).
Generate and register a uniquely named client-side handler that filters the child column's value list to the options matching the parent column's selected value (BR-CTL-001, BR-CTL-002, BR-CTL-003).

Context¶

Namespace: SAIF.Presentation.Web.Controls.V2
Assembly/package: SAIF.Presentation.Web.Controls.Infragistics111 (packaged as source into SAIF.BOF.Presentation.Web.Infragistics111)
Base class: System.Web.UI.Control (.NET Base Class Library; not a vendor or SAIF framework type)

Public members¶

Member	Signature	Purpose
`Column1`	`Public Property Column1() As Infragistics.WebUI.UltraWebGrid.UltraGridColumn`	The parent (filtering) grid column whose selected value drives which options appear in `Column2`.
`Column2`	`Public Property Column2() As Infragistics.WebUI.UltraWebGrid.UltraGridColumn`	The child (filtered) grid column whose value list is rebuilt from the parent column's selection.
`List1`	`Public Property List1() As IEnumerable`	The data source bound to `Column1`'s value list.
`List2`	`Public Property List2() As IEnumerable`	The data source bound to `Column2`'s value list.
`List1Code`	`Public Property List1Code() As String`	Name of the property on `List1` items supplying the value member for `Column1`'s value list.
`List2Code`	`Public Property List2Code() As String`	Name of the property on `List2` items supplying the value member for `Column2`'s value list.
`List1Display`	`Public Property List1Display() As String`	Name of the property on `List1` items supplying the display member for `Column1`'s value list.
`List2Display`	`Public Property List2Display() As String`	Name of the property on `List2` items supplying the display member for `Column2`'s value list.
`List2Key`	`Public Property List2Key() As String`	Name of the property on `List2` items holding the parent code used to group child options under their parent (BR-CTL-002).
`l1`	`Public l1 As New ArrayList`	The flattened `ListItem` projection of `List1`, built by `DataBind` and read by `GenerateJavaScript` to emit the parent `switch` cases.
`l2`	`Public l2 As New ArrayList`	The flattened `ListItem` projection of `List2`, built by `DataBind` and read by `GenerateJavaScript` to emit each parent case's filtered child options.
`DataBind`	`Public Overrides Sub DataBind()`	Binds both grid columns' value lists, projects both sources into `l1`/`l2`, wires the grid's `BeforeEnterEditModeHandler`, and registers the generated cascade script; see Cascade grid drop-down value lists.
`GenerateJavaScript`	`Public Function GenerateJavaScript() As String`	Builds and returns the `BeforeEdit<Column2Key>` client function that replaces the child column's value list based on the parent cell value; see Generate the cascade script.

Behavioral notes¶

DataBind calls GenerateJavaScript() twice — once discarding the result, then again to register the returned script — which is redundant work with no observable side effect from the discarded call.*
Generated script values (item codes and descriptions) are concatenated into JavaScript string literals without HTML/JS encoding, which is a script-injection risk if list values are influenced by user input (BR-CTL-006).**
DataBind has no null guard on Column1/Column2; an unset column raises an unhandled NullReferenceException.

Constraints and usage notes¶

Option Strict is Off in this project, and DataBind's reflection-based projection relies on late-bound TypeConverter conversion; only properties whose TypeConverter can target System.String contribute to l1/l2 (BR-CTL-005).
Behavior depends on the Infragistics 11.1 UltraWebGrid client-side API (igtbl_getColumnById, igtbl_getRowById, getCellFromKey) and is version-locked to Infragistics35.WebUI.UltraWebGrid.v11.1.*

Note: Statements marked with * were inferred from code structure, naming conventions, or contextual evidence where direct confirmation was not available in source artifacts. Statements marked with ** could not be confirmed; treat as unknown until verified.

Sources¶

SAIF.Presentation.Web.Controls.Infragistics111/clsDropDownController.vb