71 lines
3.1 KiB
C#
71 lines
3.1 KiB
C#
|
namespace Caliburn.Micro.Core {
|
|||
|
using System;
|
|||
|
using System.Collections.Generic;
|
|||
|
|
|||
|
/// <summary>
|
|||
|
/// Used to gather the results from multiple child elements which may or may not prevent closing.
|
|||
|
/// </summary>
|
|||
|
/// <typeparam name="T">The type of child element.</typeparam>
|
|||
|
public class DefaultCloseStrategy<T> : ICloseStrategy<T> {
|
|||
|
readonly bool closeConductedItemsWhenConductorCannotClose;
|
|||
|
|
|||
|
/// <summary>
|
|||
|
/// Creates an instance of the class.
|
|||
|
/// </summary>
|
|||
|
/// <param name="closeConductedItemsWhenConductorCannotClose">Indicates that even if all conducted items are not closable, those that are should be closed. The default is FALSE.</param>
|
|||
|
public DefaultCloseStrategy(bool closeConductedItemsWhenConductorCannotClose = false) {
|
|||
|
this.closeConductedItemsWhenConductorCannotClose = closeConductedItemsWhenConductorCannotClose;
|
|||
|
}
|
|||
|
|
|||
|
/// <summary>
|
|||
|
/// Executes the strategy.
|
|||
|
/// </summary>
|
|||
|
/// <param name="toClose">Items that are requesting close.</param>
|
|||
|
/// <param name="callback">The action to call when all enumeration is complete and the close results are aggregated.
|
|||
|
/// The bool indicates whether close can occur. The enumerable indicates which children should close if the parent cannot.</param>
|
|||
|
public void Execute(IEnumerable<T> toClose, Action<bool, IEnumerable<T>> callback) {
|
|||
|
using (var enumerator = toClose.GetEnumerator()) {
|
|||
|
Evaluate(new EvaluationState(), enumerator, callback);
|
|||
|
}
|
|||
|
}
|
|||
|
|
|||
|
void Evaluate(EvaluationState state, IEnumerator<T> enumerator, Action<bool, IEnumerable<T>> callback) {
|
|||
|
var guardPending = false;
|
|||
|
do {
|
|||
|
if (!enumerator.MoveNext()) {
|
|||
|
callback(state.FinalResult, closeConductedItemsWhenConductorCannotClose ? state.Closable : new List<T>());
|
|||
|
break;
|
|||
|
}
|
|||
|
|
|||
|
var current = enumerator.Current;
|
|||
|
var guard = current as IGuardClose;
|
|||
|
if (guard != null) {
|
|||
|
guardPending = true;
|
|||
|
guard.CanClose(canClose => {
|
|||
|
guardPending = false;
|
|||
|
if (canClose) {
|
|||
|
state.Closable.Add(current);
|
|||
|
}
|
|||
|
|
|||
|
state.FinalResult = state.FinalResult && canClose;
|
|||
|
|
|||
|
if (state.GuardMustCallEvaluate) {
|
|||
|
state.GuardMustCallEvaluate = false;
|
|||
|
Evaluate(state, enumerator, callback);
|
|||
|
}
|
|||
|
});
|
|||
|
state.GuardMustCallEvaluate = state.GuardMustCallEvaluate || guardPending;
|
|||
|
} else {
|
|||
|
state.Closable.Add(current);
|
|||
|
}
|
|||
|
} while (!guardPending);
|
|||
|
}
|
|||
|
|
|||
|
class EvaluationState {
|
|||
|
public readonly List<T> Closable = new List<T>();
|
|||
|
public bool FinalResult = true;
|
|||
|
public bool GuardMustCallEvaluate;
|
|||
|
}
|
|||
|
}
|
|||
|
}
|