/// <summary>
/// Get the value of the designer property for this model item.
/// If there is not a value then create one using the factory.
/// </summary>
/// <typeparam name="T">Property value type.</typeparam>
/// <param name="item">Model item.</param>
/// <param name="property">Designer property.</param>
/// <param name="factory">A function to initialize the designer property value.</param>
/// <returns>Designer property value.</returns>
public static T GetDesignerProperty <T>(this ModelItem item, DesignerProperty <T> property, Func <ModelItem, T> factory)
{
DesignerStateDictionary dictionary = item.Context.Services.GetService <DesignerStateDictionary>();
if (dictionary == null)
{
dictionary = new DesignerStateDictionary();
item.Context.Services.Publish <DesignerStateDictionary>(dictionary);
}
StateTable table;
if (dictionary.TryGetValue(item, out table))
{
object value;
if (table.TryGetValue(property, out value))
{
return((T)value);
}
else if (factory != null)
{
T v = factory(item);
table[property] = v;
return(v);
}
}
return(default(T));
}
/// <summary>
/// Clear the value of the designer property for this model item.
/// </summary>
/// <typeparam name="T">Property value type.</typeparam>
/// <param name="item">Model item.</param>
/// <param name="property">Designer property.</param>
public static void ClearDesignerProperty <T>(this ModelItem item, DesignerProperty <T> property)
{
DesignerStateDictionary dictionary = item.Context.Services.GetService <DesignerStateDictionary>();
if (dictionary != null)
{
StateTable table;
if (dictionary.TryGetValue(item, out table))
{
table.Remove(property);
}
if (table != null && table.Count == 0)
{
dictionary.Remove(item);
}
}
}
/// <summary>
/// Set the value of the designer property for this model item.
/// </summary>
/// <typeparam name="T">Property value type.</typeparam>
/// <param name="item">Model item.</param>
/// <param name="property">Designer property.</param>
/// <param name="value">Designer property value.</param>
public static void SetDesignerProperty <T>(this ModelItem item, DesignerProperty <T> property, T value)
{
DesignerStateDictionary dictionary = item.Context.Services.GetService <DesignerStateDictionary>();
if (dictionary == null)
{
dictionary = new DesignerStateDictionary();
item.Context.Services.Publish <DesignerStateDictionary>(dictionary);
}
StateTable table;
if (!dictionary.TryGetValue(item, out table))
{
table = new StateTable();
dictionary[item] = table;
}
table[property] = value;
}
/// <summary>
/// Get the value of the designer property for this model item.
/// </summary>
/// <typeparam name="T">Property value type.</typeparam>
/// <param name="item">Model item.</param>
/// <param name="property">Designer property.</param>
/// <returns>Designer property value.</returns>
public static T GetDesignerProperty <T>(this ModelItem item, DesignerProperty <T> property)
{
return(GetDesignerProperty <T>(item, property, null));
}