/// <summary>
/// Returns strongly-typed custom properties for pages deriving from _Layout.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="viewData">The page's ViewData.</param>
/// <returns>An object containing strongly-typed properties.</returns>
public static LayoutData Layout <T>(this ViewDataDictionary <T> viewData)
{
const string LayoutField = "Layout";
viewData.CheckNotNull(nameof(viewData));
if (viewData[LayoutField] == null)
{
viewData[LayoutField] = new LayoutData();
}
return((LayoutData)viewData[LayoutField]);
}
