/// <summary>
/// Based on a list of Expressions get a IObservedChanged for the value
/// of the last property in the chain if possible.
/// The Expressions are property chains. Eg Property1.Property2.Property3
/// The method will make sure that each Expression can get a value along the way
/// and get each property until each expression is evaluated.
/// </summary>
/// <param name="changeValues">A IObservedChanged for the value.</param>
/// <param name="current">The object that starts the property chain.</param>
/// <param name="expressionChain">A list of expressions which will point towards a property or field.</param>
/// <returns>If the value was successfully retrieved or not.</returns>
public static bool TryGetAllValuesForPropertyChain(out IObservedChange <object, object>[] changeValues, object current, IEnumerable <Expression> expressionChain)
{
int currentIndex = 0;
var expressions = expressionChain.ToList();
changeValues = new IObservedChange <object, object> [expressions.Count()];
foreach (Expression expression in expressions.SkipLast(1))
{
if (current == null)
{
changeValues[currentIndex] = null;
return(false);
}
var sender = current;
current = GetValueFetcherOrThrow(expression.GetMemberInfo())(current, expression.GetArgumentsArray());
changeValues[currentIndex] = new ObservedChange <object, object>(sender, expression, current);
currentIndex++;
}
if (current == null)
{
changeValues[currentIndex] = null;
return(false);
}
Expression lastExpression = expressions.Last();
changeValues[currentIndex] = new ObservedChange <object, object>(current, lastExpression, GetValueFetcherOrThrow(lastExpression.GetMemberInfo())(current, lastExpression.GetArgumentsArray()));
return(true);
}
/// <summary>
/// Based on a list of Expressions get the value of the last property in the chain if possible.
/// The Expressions are typically property chains. Eg Property1.Property2.Property3
/// The method will make sure that each Expression can get a value along the way
/// and get each property until each expression is evaluated.
/// </summary>
/// <param name="changeValue">A output value where to store the value if the value can be fetched.</param>
/// <param name="current">The object that starts the property chain.</param>
/// <param name="expressionChain">A list of expressions which will point towards a property or field.</param>
/// <typeparam name="TValue">The type of the end value we are trying to get.</typeparam>
/// <returns>If the value was successfully retrieved or not.</returns>
public static bool TryGetValueForPropertyChain <TValue>(out TValue changeValue, object current, IEnumerable <Expression> expressionChain)
{
var expressions = expressionChain.ToList();
foreach (Expression expression in expressions.SkipLast(1))
{
if (current == null)
{
changeValue = default(TValue);
return(false);
}
current = GetValueFetcherOrThrow(expression.GetMemberInfo())(current, expression.GetArgumentsArray());
}
if (current == null)
{
changeValue = default(TValue);
return(false);
}
Expression lastExpression = expressions.Last();
changeValue = (TValue)GetValueFetcherOrThrow(lastExpression.GetMemberInfo())(current, lastExpression.GetArgumentsArray());
return(true);
}
public static bool TryGetValueForPropertyChain <TValue>(out TValue changeValue, object current, string[] propNames)
{
foreach (var propName in propNames.SkipLast(1))
{
if (current == null)
{
changeValue = default(TValue);
return(false);
}
current = GetValueFetcherOrThrow(current.GetType(), propName)(current);
}
if (current == null)
{
changeValue = default(TValue);
return(false);
}
changeValue = (TValue)GetValueFetcherOrThrow(current.GetType(), propNames.Last())(current);
return(true);
}
public static bool TryGetAllValuesForPropertyChain(out IObservedChange <object, object>[] changeValues, object current, string[] propNames)
{
int currentIndex = 0;
changeValues = new IObservedChange <object, object> [propNames.Length];
foreach (var propName in propNames.SkipLast(1))
{
if (current == null)
{
changeValues[currentIndex] = null;
return(false);
}
var box = new ObservedChange <object, object> {
Sender = current, PropertyName = propName
};
current = GetValueFetcherOrThrow(current.GetType(), propName)(current);
box.Value = current;
changeValues[currentIndex] = box;
currentIndex++;
}
if (current == null)
{
changeValues[currentIndex] = null;
return(false);
}
changeValues[currentIndex] = new ObservedChange <object, object> {
Sender = current,
PropertyName = propNames.Last(),
Value = GetValueFetcherOrThrow(current.GetType(), propNames.Last())(current)
};
return(true);
}
