Fix AutomationProperties.Name binding errors for HintAssist.Hint

[Copilot]

Problem

AutomationProperties.Name binding errors were occurring in MaterialDesign controls (NumericUpDown, TextBox, ComboBox, etc.) when HintAssist.Hint contained non-string values. Since HintAssist.Hint is of type object, binding it directly to AutomationProperties.Name (which expects a string) caused WPF binding errors in the output window.

Solution

Created a new AutomationPropertiesNameConverter in the Internal namespace that safely converts any value to a string for use with AutomationProperties.Name bindings:

• If the value is already a string, returns it unchanged
• For null or non-string values, returns an empty string

The converter was applied to all AutomationProperties.Name bindings that reference HintAssist.Hint across the theme files.

Changes

New Files

• AutomationPropertiesNameConverter.cs - Internal value converter that safely converts objects to strings for AutomationProperties.Name
• AutomationPropertiesNameConverterTests.cs - Comprehensive unit tests covering string, null, and non-string inputs

Modified Files

Applied the converter to 8 AutomationProperties.Name bindings in 7 XAML theme files:

• MaterialDesignTheme.AutoSuggestBox.xaml
• MaterialDesignTheme.ComboBox.xaml
• MaterialDesignTheme.DatePicker.xaml
• MaterialDesignTheme.NumericUpDown.xaml
• MaterialDesignTheme.PasswordBox.xaml (2 occurrences - standard and reveal styles)
• MaterialDesignTheme.TextBox.xaml
• MaterialDesignTheme.TimePicker.xaml

Example Change

Before:

<Setter Property="AutomationProperties.Name" 
        Value="{Binding Path=(wpf:HintAssist.Hint), RelativeSource={RelativeSource Self}}" />

After:

<Setter Property="AutomationProperties.Name" 
        Value="{Binding Path=(wpf:HintAssist.Hint), RelativeSource={RelativeSource Self}, 
                Converter={x:Static convertersInternal:AutomationPropertiesNameConverter.Instance}}" />

Impact

• ✅ Eliminates binding errors when HintAssist.Hint contains non-string values
• ✅ Improves accessibility support by ensuring AutomationProperties.Name always has a valid string value
• ✅ No breaking changes - existing string hints continue to work as before
• ✅ Consistent solution applied across all affected controls

Fixes #3941

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Binding Errors on AutomationProperty.Name</issue_title>
<issue_description>### Bug explanation

In 5.3.0 release, create a new NumericUpDown control with the default style.

Observered: Binding Error on the AutomationProperties.Name property

Expected: No binding errors

I think the correct solution here is to create a value converter that can be applied to the binding. If the value is a string returning it, otherwise simply return empty string.

Version

5.3.0</issue_description>

<agent_instructions>Find all of the controls that bind the AutomationProperties.Name to HintAssist.Hint and apply the value converter to those binding.</agent_instructions>

Comments on the Issue (you are @copilot in this section)

Fixes #3945

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[Keboo]

@copilot rename this to AutomationPropertiesNameConverter and move to the internal namespace

[Copilot]

Done. Renamed to AutomationPropertiesNameConverter and moved to the Internal namespace in commit 9619ddc.