private static object GetInstanceOfStep(string step, object instance)
{
Type type = instance.GetType();
if (step.StartsWith("[", StringComparison.InvariantCulture) && step.EndsWith("]", StringComparison.InvariantCulture))
{
int index;
string indexStr = step.Substring(1, step.Length - 2);
if (!int.TryParse(indexStr, out index))
{
throw new ArgumentException("Couldn't parse an index from the path step '" + step + "'.");
}
// We need to check the current type to see if we can treat it as a list
if (type.IsArray)
{
Array array = (Array)instance;
if (index < 0 || index >= array.Length)
{
return(null);
}
return(array.GetValue(index));
}
else if (typeof(IList).IsAssignableFrom(type))
{
IList list = (IList)instance;
if (index < 0 || index >= list.Count)
{
return(null);
}
return(list[index]);
}
else if (type.ImplementsOpenGenericInterface(typeof(IList <>)))
{
Type elementType = type.GetArgumentsOfInheritedOpenGenericInterface(typeof(IList <>))[0];
Type listType = typeof(IList <>).MakeGenericType(elementType);
MethodInfo getItemMethod = listType.GetMethod("get_Item", BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
try
{
return(getItemMethod.Invoke(instance, new object[] { index }));
}
catch (Exception)
{
return(null);
}
}
}
else if (step.StartsWith("{", StringComparison.InvariantCultureIgnoreCase) && step.EndsWith("}", StringComparison.InvariantCultureIgnoreCase))
{
if (type.ImplementsOpenGenericInterface(typeof(IDictionary <,>)))
{
var dictArgs = type.GetArgumentsOfInheritedOpenGenericInterface(typeof(IDictionary <,>));
object key = DictionaryKeyUtility.GetDictionaryKeyValue(step, dictArgs[0]);
Type dictType = typeof(IDictionary <,>).MakeGenericType(dictArgs);
MethodInfo getItemMethod = dictType.GetMethod("get_Item", BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance);
try
{
return(getItemMethod.Invoke(instance, new object[] { key }));
}
catch (Exception)
{
return(null);
}
}
}
else
{
string privateTypeName = null;
int plusIndex = step.IndexOf('+');
if (plusIndex >= 0)
{
privateTypeName = step.Substring(0, plusIndex);
step = step.Substring(plusIndex + 1);
}
var possibleMembers = type.GetAllMembers(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Instance).Where(n => n is FieldInfo || n is PropertyInfo);
foreach (var member in possibleMembers)
{
if (member.Name == step)
{
if (privateTypeName != null && member.DeclaringType.Name != privateTypeName)
{
continue;
}
return(member.GetMemberValue(instance));
}
}
}
return(null);
}
