/// <summary>
/// Searches for a subrange of text that has the specified attribute.
/// To search the entire document use the text pattern's document range.
/// </summary>
/// <param name="attribute">The attribute to search for.</param>
/// <param name="value">The value of the specified attribute to search for. The value must be of the exact type specified for the
/// attribute. For example when searching for font size you must specify the size in points as a double.
/// If you specify the point size as an integer then you will never get any matches due to the differing types.</param>
/// <param name="backward">true if the last occurring range should be returned instead of the first.</param>
/// <returns>A subrange with the specified attribute, or null if no such subrange exists.</returns>
public TextPatternRange FindAttribute(AutomationTextAttribute attribute, object value, bool backward)
{
Misc.ValidateArgumentNonNull(attribute, "attribute");
Misc.ValidateArgumentNonNull(value, "value"); // no text attributes can have null as a valid value
// Check that attribute value is of expected type...
AutomationAttributeInfo ai;
if (!Schema.GetAttributeInfo(attribute, out ai))
{
throw new ArgumentException(SR.Get(SRID.UnsupportedAttribute));
}
if (value.GetType() != ai.Type)
{
throw new ArgumentException(SR.Get(SRID.TextAttributeValueWrongType, attribute, ai.Type.Name, value.GetType().Name), "value");
}
// note: if we implement attributes whose values are logical elements, patterns,
// or ranges then we'll need to unwrap the objects here before passing them on to
// the provider.
if (attribute == TextPattern.CultureAttribute)
{
if (value is CultureInfo)
{
value = ((CultureInfo)value).LCID;
}
}
SafeTextRangeHandle hResultTextRange = UiaCoreApi.TextRange_FindAttribute(_hTextRange, attribute.Id, value, backward);
return(Wrap(hResultTextRange, _pattern));
}
