Error BE0065: An error occurred while attempting to transform the reflection data to a topic. When Extensions Methods to Enum.

[jenergm]

Hi there,

When matching Extensions Methods to Enum throws an Error BE0065: An error occurred while attempting to transform the reflection data to a topic. The error message was: System.NullReferenceException

/// <summary>
/// Page size enum options
/// </summary>
public enum PageSize
{
    /// <summary>
    /// A4 size 21cm x 29.7cm.
    /// </summary>
    A4,
    /// <summary>
    /// Letter size 21.59cm x 27.94cm
    /// </summary>
    Letter,
    /// <summary>
    /// Office size 21.59cm x 35.56cm
    /// </summary>
    Office
}

/// <summary>
/// Extension methods for Page Size helper.
/// </summary>
public static class PageSizeExtension
{
    /// <summary>
    /// Get the size for a pageSize enum.
    /// </summary>
    /// <param name="pageSize">The pageSize enum item at issue.</param>
    /// <returns>The size (width and height) of the page at issue.</returns>
    public static Size Size (this PageSize pageSize)
    {
        switch (pageSize)
        {
            case PageSize.A4: return new Size() { Width = "21cm", Height = "29.7cm" };
            case PageSize.Letter: return new Size() { Width = "21.59cm", Height = "27.94cm" };
            case PageSize.Office: return new Size() { Width = "21.59cm", Height = "35.56cm" };
            default : return null;
        }
    }
}

I've edited API Filter in Project Properties -> Visibility -> Edit API Filter to disable PageSizeExtension class and bypass the error. But I know it's not the solution even a workarround. But I needed build the project.

That is about: Sandcastle Help File Builder and Tools Version: 2024.2.18.0