---
title: Validate a bound control and reflect state
summary: Surfaces the bound business object's own validation errors on the control and page.
status: draft
owner: SAIF documentation generator
last_reviewed: 2026-08-17
library: SAIF.Presentation.Web.Controls.AJAX.Infragistics103
reference_type: package
operation_id: OP-AJAX-003
trigger: Called from BindToControl/BindToObject when auto-validation is enabled, or explicitly by page code
---

# Validate a bound control and reflect state

`AutoBindControlAncestor.Validate()` surfaces the bound business object's own `IDataErrorInfo` validation messages on the control's UI and on a shared page error label. This library does not define what constitutes invalid data itself — validity is entirely determined by the bound object's own validation implementation.

| Field | Value |
| --- | --- |
| **Operation ID** | OP-AJAX-003 |
| **Trigger** | Invoked from [Auto-bind an individual control to its bound object](auto-bind-an-individual-control-to-its-bound-object.md) (`BindToControl`/`BindToObject`) when auto-validation is enabled, or called explicitly by page code |
| **Inputs** | `IsValid`, `ErrorMessages` (sourced from the bound object's `IDataErrorInfo` implementation) |
| **Outputs** | Page error label text (`LblErrorMsg`), control background color |
| **Primary components** | `AutoBindControlAncestor.Validate`, `AutoBindControlAncestor.GetErrorMessages`, `AutoBindControlAncestor.StyleControl` |
| **Entry point** | `SAIF.Presentation.Web.Controls.AJAX.Infragistics103\AutoBindControlAncestor.vb` |

## Steps

1. `ErrorMessages` getter calls `GetErrorMessages()`: if `IsBound`, casts `BoundObject` to `IDataErrorInfo` and reads `Item(BindProperty)` — this is where the business object's own validation/business-rule engine surfaces error text**; the raw error string is split on `vbCrLf` into an array. This enforces [BR-AJAX-001](../business-rules.md#br-ajax-001-auto-bound-controls-display-validation-errors-sourced-from-the-bound-objects-idataerrorinfo).
2. `Validate()` concatenates unique error messages (skipping duplicates already present) into an HTML string.
3. `BindingUtility.SetObjectValue(PageErrorLabel, "Text", messages)` writes the combined message to a page control located by `PageErrorLabel` (searches `Page.Controls` recursively for a control whose `UniqueID` case-insensitively matches `"LblErrorMsg"`).
   - If no such control exists, `GetControl` returns `Nothing` and the reflection-based `SetObjectValue` silently no-ops (swallowed `NotSupportedException`)*.
4. `StyleControl(IsValid)` is called (`MustOverride`, implemented per concrete control) — colors the underlying editor's `BackColor` red when invalid, or resets it (`Color.FromName("0")`, effectively black/default) when valid.

   > **Origin**: Step 1's error-text source (the bound business object's `IDataErrorInfo.Item` implementation) is defined in the referenced business-object library (e.g., `SAIF.Business`), not this library — the enforcement/business-rule logic there is out of scope for this analysis and not traced here**.

## Process flow

The following diagram visualizes this operation's control flow.

```mermaid
flowchart TD
	Start([Validate called]) --> Bound{IsBound?}
	Bound -->|No| NoMsgs([ErrorMessages empty])
	Bound -->|Yes| GetErr[Read IDataErrorInfo.Item BindProperty]
	GetErr --> Split[Split error text into messages]
	Split --> Concat[Concatenate unique messages]
	Concat --> WriteLabel[Write combined text to LblErrorMsg]
	WriteLabel --> Style[StyleControl colors background red/default]
```

## Failure and edge-case behavior
- No page control named `LblErrorMsg` exists: `GetControl` returns `Nothing`; `SetObjectValue` swallows the resulting `NotSupportedException` and the message is never displayed*.
- `BoundObject` is not bound (`IsBound = False`): `ErrorMessages` returns an empty array, so `IsValid` reports `True`.

## Related documentation
- [Operations and processes](../operations-processes.md)
- [Business rules](../business-rules.md)
- [SQL catalog](../sql/index.md)
- [Database tables](../database-tables.md)

> **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.AJAX.Infragistics103\AutoBindControlAncestor.vb`
- `SAIF.Presentation.Web.Controls.AJAX.Infragistics103\BindingUtility.vb`