public bool Evaluate(IDataDescriptor source, out IDataDescriptor result)
{
result = null;
object value = source.Value;
if (value == null)
{
return(false);
}
ParameterInfo[] indexerParams = IndexerDataDescriptor.GetIndexerTypes(value.GetType());
object[] convertedIndices;
// Search indexer on source type
if (indexerParams != null && ReflectionHelper.ConsumeParameters(_indices,
indexerParams, false, out convertedIndices))
{ // Index on Item property
result = new IndexerDataDescriptor(value, convertedIndices);
return(true);
}
if (ReflectionHelper.ConvertTypes(_indices, new Type[] { typeof(int) },
out convertedIndices))
{ // Collection index
if (!ReflectionHelper.GetEnumerationEntryByIndex(value, (int)convertedIndices[0], out result))
{
throw new XamlBindingException("Index '{0}' cannot be applied on '{1}'",
ToString(), value);
}
return(true);
}
return(false);
}
public IDataDescriptor Retarget(object newTarget)
{
if (newTarget == null)
{
throw new NullReferenceException("Target object 'null' is not supported");
}
if (!IndicesCompatible(newTarget.GetType(), _indices))
{
throw new InvalidOperationException(
"Type of new target object is not compatible with the indices of this property descriptor");
}
IndexerDataDescriptor result = new IndexerDataDescriptor(newTarget, _indices);
return(result);
}
/// <summary>
/// Returns a data descriptor for the access to a collection-like instance
/// <paramref name="maybeCollection"/> with an <paramref name="index"/>.
/// </summary>
/// <param name="maybeCollection">Instance which may be collection-like, like an
/// <see cref="IList{T}"/>, <see cref="ICollection{T}"/> or <see cref="IEnumerable{T}"/>.
/// The returned data descriptor will allow to read the value, and for an
/// <see cref="IList{T}"/> it will also be writeable.</param>
/// <param name="index">Index to access the collection-like instance.</param>
/// <param name="result">Returns the data descriptor for the access to the
/// <paramref name="index"/>th entry in <paramref name="maybeCollection"/>.</param>
/// <returns><c>true</c>, if <paramref name="maybeCollection"/> is a collection-like
/// instance and could be accessed by the specified <paramref name="index"/>, else
/// <c>false</c>.</returns>
public static bool GetEnumerationEntryByIndex(object maybeCollection, int index,
out IDataDescriptor result)
{
if (maybeCollection is IList)
{
result = new IndexerDataDescriptor(maybeCollection, new object[] { index });
return(true);
}
if (maybeCollection is IEnumerable)
{
int i = 0;
foreach (object o in (IEnumerable)maybeCollection)
{
if (i++ == index)
{
result = new ValueDataDescriptor(o);
return(true);
}
}
throw new XamlBindingException("Index '{0}' is out of range (# elements={1})", index, i);
}
result = null;
return(false);
}
/// <summary>
/// Returns the information if the specified <paramref name="other"/> descriptor
/// is targeted at the same list index on the same list.
/// </summary>
/// <param name="other">Other descriptor whose target object and property should be compared.</param>
public bool TargetEquals(IndexerDataDescriptor other)
{
return(_target.Equals(other._target) && IndicesEquals(other._indices));
}
/// <summary>
/// Returns a data descriptor for the access to a collection-like instance
/// <paramref name="maybeCollection"/> with an <paramref name="index"/>.
/// </summary>
/// <param name="maybeCollection">Instance which may be collection-like, like an
/// <see cref="IList{T}"/>, <see cref="ICollection{T}"/> or <see cref="IEnumerable{T}"/>.
/// The returned data descriptor will allow to read the value, and for an
/// <see cref="IList{T}"/> it will also be writeable.</param>
/// <param name="index">Index to access the collection-like instance.</param>
/// <param name="result">Returns the data descriptor for the access to the
/// <paramref name="index"/>th entry in <paramref name="maybeCollection"/>.</param>
/// <returns><c>true</c>, if <paramref name="maybeCollection"/> is a collection-like
/// instance and could be accessed by the specified <paramref name="index"/>, else
/// <c>false</c>.</returns>
public static bool GetEnumerationEntryByIndex(object maybeCollection, int index,
out IDataDescriptor result)
{
if (maybeCollection is IList)
{
result = new IndexerDataDescriptor(maybeCollection, new object[] { index });
return true;
}
if (maybeCollection is IEnumerable)
{
int i = 0;
foreach (object o in (IEnumerable)maybeCollection)
{
if (i++ == index)
{
result = new ValueDataDescriptor(o);
return true;
}
}
throw new XamlBindingException("Index '{0}' is out of range (# elements={1})", index, i);
}
result = null;
return false;
}
/// <summary>
/// Returns the information if the specified <paramref name="other"/> descriptor
/// is targeted at the same list index on the same list.
/// </summary>
/// <param name="other">Other descriptor whose target object and property should be compared.</param>
public bool TargetEquals(IndexerDataDescriptor other)
{
return _target.Equals(other._target) && IndicesEquals(other._indices);
}
public IDataDescriptor Retarget(object newTarget)
{
if (newTarget == null)
throw new NullReferenceException("Target object 'null' is not supported");
if (!IndicesCompatible(newTarget.GetType(), _indices))
throw new InvalidOperationException(
"Type of new target object is not compatible with the indices of this property descriptor");
IndexerDataDescriptor result = new IndexerDataDescriptor(newTarget, _indices);
return result;
}
