//------------------------------------------------------------------------------------
/// <summary>
/// Ensure that the given property is present in the in-memory cache - if not, the
/// property is populated with its initial value from the backing store (or with a
/// default empty value if the item is not a persisted type).
/// </summary>
//------------------------------------------------------------------------------------
private ItemProperty EnsureItemProperty(string dsPropName, string publicPropName, PropType type)
{
if (publicPropName == null)
{
throw new ApplicationException();
}
ItemProperty itemProperty = null;
lock (SyncLockItemProperties)
{
if (!ItemProperties.TryGetValue(publicPropName, out itemProperty))
{
itemProperty = new ItemProperty(this, dsPropName, publicPropName, type);
if (IsPersisted)
{
itemProperty.ReadFromStore();
}
ItemProperties.Add(publicPropName, itemProperty);
}
}
return(itemProperty);
}
public object GetRefreshedBackingValue <T>(Expression <Func <T> > expression)
{
string publicPropName = StringUtils.GetExpressionName(expression);
if (ItemProperties.ContainsKey(publicPropName))
{
ItemProperty itemProperty = ItemProperties[publicPropName];
itemProperty.ReadFromStore();
return(itemProperty.BackingValue);
}
return(null);
}
//------------------------------------------------------------------------------------
/// <summary>
/// Reads the latest value of the given property from the backing store, and if the
/// value is different what's currently in memory, sets the value of the given
/// property to the new value.
/// </summary>
//------------------------------------------------------------------------------------
public void SyncPropertyFromStore(ItemProperty itemProperty)
{
// Read the latest value from the backing store
ItemProperty propertyFromStore = new ItemProperty(this, itemProperty.DSPropName, itemProperty.PublicPropName, itemProperty.PropertyType);
propertyFromStore.ReadFromStore();
// If the backing store value doesn't match in the in-memory cached value, update
// the object model with the new value.
if (!propertyFromStore.IsEqual(itemProperty))
{
// First set the backing value of our in-memory property to the value from the store
itemProperty.BackingValue = propertyFromStore.BackingValue;
// Use the same value to set the current value (via the object model) so that
// backing and current values are sync'd, and all UI side-effects are enacted.
SetPublicProperty(itemProperty.PublicPropName, propertyFromStore.BackingValue);
}
}