/// <summary>Traverses the object graph rooted at <c>obj</c> by reflecting over the objects in the object's fields,
/// their fields, etc. For each object visited in the graph, calls objFilter. If objFilter
/// returns false, the object passed to objFilter isn't recursed, else it is.
///
/// If a non-null value is provided for <c>parent</c>, any references to the <c>parent</c> object are
/// ignored and are neither traversed nor passed to objFilter.
///
/// <c>cookie</c> is a caller-defined state object that is passed to objFilter directly.
/// </summary>
///
/// <param name="cookie"></param>
/// <param name="obj"></param>
/// <param name="parent"></param>
/// <param name="objFilter"></param>
///
/// <returns>A list of all the objects in the graph, not including those that were excluded
/// by objFilter. This list will not contain duplicates, even if an object
/// was encountered multiple times during the recursion.</returns>
public ICollection RecurseObjectGraph(Object cookie, Object obj, Object parent, ProcessObjectFilterDelegate objFilter)
{
if (obj == null) {
throw new ArgumentNullException("obj");
}
if (objFilter == null) {
throw new ArgumentNullException("obj");
}
//Start the list of objects
ArrayList objList = new ArrayList();
RecurseObjectGraphInternal(objList, cookie, null, obj, parent, objFilter);
return objList;
}
/// <summary>Internal recursive function that actually does the recursion</summary>
///
/// <param name="cookie"></param>
/// <param name="field"></param>
/// <param name="obj"></param>
/// <param name="parent"></param>
/// <param name="objFilter"></param>
private void RecurseObjectGraphInternal(IList objList, Object cookie, FieldInfo field, Object obj, Object parent, ProcessObjectFilterDelegate objFilter)
{
//First, pass this object through the object processor. If it indicates
//not to recurse further, stop now
if (!objFilter(cookie, field, obj, parent)) {
return;
}
//Add this object to the list of objects that have been processed
objList.Add(obj);
//Get all the fields for this type, and for each one, process its object graph
foreach (FieldInfo fi in GetTypeFields(obj.GetType())) {
//Process the value of the field
RecurseFieldValue(objList,
cookie,
fi,
fi.GetValue(obj),
obj,
parent,
objFilter);
}
if (obj is Array) {
//An array object. Process each of its elements as well
foreach (Object arrayObj in (Array)obj) {
RecurseFieldValue(objList,
cookie,
field,
arrayObj,
obj,
parent,
objFilter);
}
}
}
/// Encapsulates the logic to recurse the (potentially null) value of a field
private void RecurseFieldValue(IList objList, Object cookie, FieldInfo field, Object fieldValue, Object obj, Object parent, ProcessObjectFilterDelegate objFilter)
{
//If the field value is null, ignore it
if (fieldValue == null) {
return;
}
//If this is the current object's parent, ignore it, since it will
//already have been processed
if (fieldValue == parent) {
return;
}
//If this is already in the list of objects in the graph, don't process
//it again
if (objList.Contains(fieldValue)) {
return;
}
//Process this object's graph
RecurseObjectGraphInternal(objList,
cookie,
field,
fieldValue,
obj,
objFilter);
}
