/// <summary>
/// Generates semantic markup (HTML/RDFa attributes) for a given property.
/// </summary>
/// <param name="htmlHelper">The HtmlHelper instance on which the extension method operates.</param>
/// <param name="propertyExpression">A parameterless lambda expression which evaluates to a property of the current Entity Model.</param>
/// <param name="index">The index of the property value (for multi-value properties).</param>
/// <returns>The semantic markup (HTML/RDFa attributes).</returns>
public static MvcHtmlString DxaPropertyMarkup(this HtmlHelper htmlHelper, Expression <Func <object> > propertyExpression, int index = 0)
{
MemberExpression memberExpression = propertyExpression.Body as MemberExpression;
if (memberExpression == null)
{
UnaryExpression boxingExpression = propertyExpression.Body as UnaryExpression;
if (boxingExpression != null)
{
memberExpression = boxingExpression.Operand as MemberExpression;
}
}
if (memberExpression == null)
{
throw new DxaException(
string.Format("Unexpected expression provided to DxaPropertyMarkup: {0}. Expecting a lambda which evaluates to an Entity Model property.", propertyExpression.Body.GetType().Name)
);
}
Expression <Func <object> > entityExpression = Expression.Lambda <Func <object> >(memberExpression.Expression);
Func <object> entityLambda = entityExpression.Compile();
object entity = entityLambda.Invoke();
EntityModel entityModel = entity as EntityModel;
if (entityModel == null)
{
throw new DxaException(
string.Format("Unexpected type used in DxaPropertyMarkup expression: {0}. Expecting a lambda which evaluates to an Entity Model property.", entity)
);
}
return(Markup.RenderPropertyAttributes(entityModel, memberExpression.Member, index));
}
/// <summary>
/// Generates semantic markup (HTML/RDFa attributes) for a given property.
/// </summary>
/// <param name="htmlHelper">The HtmlHelper instance on which the extension method operates.</param>
/// <param name="propertyExpression">A parameterless lambda expression which evaluates to a property of the current Entity Model.</param>
/// <param name="index">The index of the property value (for multi-value properties).</param>
/// <returns>The semantic markup (HTML/RDFa attributes).</returns>
public static MvcHtmlString DxaPropertyMarkup(this HtmlHelper htmlHelper, Expression <Func <object> > propertyExpression, int index = 0)
{
MemberExpression memberExpression = propertyExpression.Body as MemberExpression;
if (memberExpression == null)
{
UnaryExpression boxingExpression = propertyExpression.Body as UnaryExpression;
if (boxingExpression != null)
{
memberExpression = boxingExpression.Operand as MemberExpression;
}
}
if (memberExpression == null)
{
throw new DxaException(
$"Unexpected expression provided to DxaPropertyMarkup: {propertyExpression.Body.GetType().Name}. Expecting a lambda which evaluates to an Entity Model property."
);
}
object subject;
MemberExpression subjectExpression = memberExpression.Expression as MemberExpression;
if (subjectExpression != null && subjectExpression.Member.Name == "Model")
{
// Often the subject of the property expression is the current Model. For example: () => Model.Headline
// This is a shortcut to prevent having to compile the subject expression for that case.
subject = htmlHelper.ViewData.Model;
}
else
{
Expression <Func <object> > entityExpression = Expression.Lambda <Func <object> >(memberExpression.Expression);
Func <object> entityLambda = entityExpression.Compile();
subject = entityLambda.Invoke();
}
EntityModel entityModel = subject as EntityModel;
if (entityModel == null)
{
throw new DxaException(
$"Unexpected type used in DxaPropertyMarkup expression: {subject}. Expecting a lambda which evaluates to an Entity Model property."
);
}
return(Markup.RenderPropertyAttributes(entityModel, memberExpression.Member, index));
}
/// <summary>
/// Generates semantic markup (HTML/RDFa attributes) for a given property of a given Entity Model.
/// </summary>
/// <param name="htmlHelper">The HtmlHelper instance on which the extension method operates.</param>
/// <param name="entity">The Entity Model.</param>
/// <param name="propertyName">The name of the property.</param>
/// <param name="index">The index of the property value (for multi-value properties).</param>
/// <returns>The semantic markup (HTML/RDFa attributes).</returns>
public static MvcHtmlString DxaPropertyMarkup(this HtmlHelper htmlHelper, EntityModel entity, string propertyName, int index = 0)
{
return(Markup.RenderPropertyAttributes(entity, propertyName, index));
}
/// <summary> /// Generates semantic markup (HTML/RDFa attributes) for a given property of the current Entity Model. /// </summary> /// <param name="htmlHelper">The HtmlHelper instance on which the extension method operates.</param> /// <param name="propertyName">The name of the property.</param> /// <param name="index">The index of the property value (for multi-value properties).</param> /// <returns>The semantic markup (HTML/RDFa attributes).</returns> public static MvcHtmlString DxaPropertyMarkup(this HtmlHelper htmlHelper, string propertyName, int index = 0) => Markup.RenderPropertyAttributes((EntityModel)htmlHelper.ViewData.Model, propertyName, index);
