/// <summary>
/// Requires that the named argument's state is valid (i.e., true).
/// </summary>
/// <param name="argState">The argument's state.</param>
/// <param name="explanation">The explanation to put in the exception.</param>
/// <param name="argName">The name of the arg to put in the exception.</param>
/// <exception cref="ArgumentException">If <paramref name="argState"/> is false.</exception>
public static void RequireArgument([DoesNotReturnIf(false)] bool argState, string explanation, string argName)
{
if (!argState)
{
throw Exceptions.NewArgumentException(explanation, argName);
}
}
/// <summary>
/// Gets the specified attribute's value.
/// </summary>
/// <param name="element">The element to get the attribute from.</param>
/// <param name="name">The name of the attribute to read.</param>
/// <returns>The value of the attribute. An <see cref="ArgumentException"/>
/// is thrown if the specified attribute isn't found.</returns>
/// <exception cref="ArgumentException">Throw if either of the arguments are null,
/// or if the specified attribute isn't found.</exception>
public static string GetAttributeValue(this XElement element, XName name)
{
string?result = GetAttributeValueN(element, name, null, false);
if (result == null)
{
throw Exceptions.NewArgumentException($"The {element.Name} element does not have a {name} attribute.");
}
else if (string.IsNullOrEmpty(result))
{
throw Exceptions.NewArgumentException($"The {element.Name} element has an empty {name} attribute.");
}
return(result);
}
