added default CancellationTokens to common methods (fixes #663)

src/Caliburn.Micro.Core/Conductor.cs

@@ -10,7 +10,7 @@ namespace Caliburn.Micro
     public partial class Conductor<T> : ConductorBaseWithActiveItem<T> where T : class
     {
         /// <inheritdoc />
-        public override async Task ActivateItemAsync(T item, CancellationToken cancellationToken)
+        public override async Task ActivateItemAsync(T item, CancellationToken cancellationToken = default)
         {
             if (item != null && item.Equals(ActiveItem))
             {
@@ -41,7 +41,7 @@ public override async Task ActivateItemAsync(T item, CancellationToken cancellat
         /// <param name="close">Indicates whether or not to close the item after deactivating it.</param>
         /// <param name="cancellationToken">The cancellation token to cancel operation.</param>
         /// <returns>A task that represents the asynchronous operation.</returns>
-        public override async Task DeactivateItemAsync(T item, bool close, CancellationToken cancellationToken)
+        public override async Task DeactivateItemAsync(T item, bool close, CancellationToken cancellationToken = default)
         {
             if (item == null || !item.Equals(ActiveItem))
             {
@@ -61,7 +61,7 @@ public override async Task DeactivateItemAsync(T item, bool close, CancellationT
         /// </summary>
         /// <param name="cancellationToken">The cancellation token to cancel operation.</param>
         /// <returns>A task that represents the asynchronous operation.</returns>
-        public override async Task<bool> CanCloseAsync(CancellationToken cancellationToken)
+        public override async Task<bool> CanCloseAsync(CancellationToken cancellationToken = default )
         {
             var closeResult = await CloseStrategy.ExecuteAsync(new[] { ActiveItem }, cancellationToken);
 

src/Caliburn.Micro.Core/ConductorBase.cs

@@ -56,7 +56,7 @@ Task IConductor.ActivateItemAsync(object item, CancellationToken cancellationTok
         /// <param name="item">The item to activate.</param>
         /// <param name="cancellationToken">A cancellation token that can be used by other objects or threads to receive notice of cancellation.</param>
         /// <returns>A task that represents the asynchronous operation.</returns>
-        public abstract Task ActivateItemAsync(T item, CancellationToken cancellationToken);
+        public abstract Task ActivateItemAsync(T item, CancellationToken cancellationToken = default);
 
         /// <summary>
         /// Deactivates the specified item.
@@ -65,7 +65,7 @@ Task IConductor.ActivateItemAsync(object item, CancellationToken cancellationTok
         /// <param name="close">Indicates whether or not to close the item after deactivating it.</param>
         /// <param name="cancellationToken">The cancellation token to cancel operation.</param>
         /// <returns>A task that represents the asynchronous operation.</returns>
-        public abstract Task DeactivateItemAsync(T item, bool close, CancellationToken cancellationToken);
+        public abstract Task DeactivateItemAsync(T item, bool close, CancellationToken cancellationToken = default);
 
         /// <summary>
         /// Called by a subclass when an activation needs processing.

src/Caliburn.Micro.Core/ConductorWithCollectionAllActive.cs

@@ -94,7 +94,7 @@ protected override async Task OnDeactivateAsync(bool close, CancellationToken ca
                 /// </summary>
                 /// <param name="cancellationToken">The cancellation token to cancel operation.</param>
                 /// <returns>A task that represents the asynchronous operation.</returns>
-                public override async Task<bool> CanCloseAsync(CancellationToken cancellationToken)
+                public override async Task<bool> CanCloseAsync(CancellationToken cancellationToken = default)
                 {
                     var closeResult = await CloseStrategy.ExecuteAsync(_items.ToList(), cancellationToken);
 
@@ -130,7 +130,7 @@ await Task.WhenAll(GetType().GetRuntimeProperties()
                 /// <param name="item">The item to activate.</param>
                 /// <param name="cancellationToken">The cancellation token to cancel operation.</param>
                 /// <returns>A task that represents the asynchronous operation.</returns>
-                public override async Task ActivateItemAsync(T item, CancellationToken cancellationToken)
+                public override async Task ActivateItemAsync(T item, CancellationToken cancellationToken = default)
                 {
                     if (item == null)
                         return;
@@ -150,7 +150,7 @@ public override async Task ActivateItemAsync(T item, CancellationToken cancellat
                 /// <param name="close">Indicates whether or not to close the item after deactivating it.</param>
                 /// <param name="cancellationToken">The cancellation token to cancel operation.</param>
                 /// <returns>A task that represents the asynchronous operation.</returns>
-                public override async Task DeactivateItemAsync(T item, bool close, CancellationToken cancellationToken)
+                public override async Task DeactivateItemAsync(T item, bool close, CancellationToken cancellationToken = default)
                 {
                     if (item == null)
                         return;
@@ -175,7 +175,7 @@ public override IEnumerable<T> GetChildren()
                     return _items;
                 }
 
-                private async Task CloseItemCoreAsync(T item, CancellationToken cancellationToken)
+                private async Task CloseItemCoreAsync(T item, CancellationToken cancellationToken = default)
                 {
                     await ScreenExtensions.TryDeactivateAsync(item, true, cancellationToken);
                     _items.Remove(item);

src/Caliburn.Micro.Core/ConductorWithCollectionOneActive.cs

@@ -63,7 +63,7 @@ public OneActive()
                 /// <param name="item">The item to activate.</param>
                 /// <param name="cancellationToken">A cancellation token that can be used by other objects or threads to receive notice of cancellation.</param>
                 /// <returns>A task that represents the asynchronous operation.</returns>
-                public override async Task ActivateItemAsync(T item, CancellationToken cancellationToken)
+                public override async Task ActivateItemAsync(T item, CancellationToken cancellationToken = default)
                 {
                     if (item != null && item.Equals(ActiveItem))
                     {
@@ -86,7 +86,7 @@ public override async Task ActivateItemAsync(T item, CancellationToken cancellat
                 /// <param name="close">Indicates whether or not to close the item after deactivating it.</param>
                 /// <param name="cancellationToken">The cancellation token to cancel operation.</param>
                 /// <returns>A task that represents the asynchronous operation.</returns>
-                public override async Task DeactivateItemAsync(T item, bool close, CancellationToken cancellationToken)
+                public override async Task DeactivateItemAsync(T item, bool close, CancellationToken cancellationToken = default)
                 {
                     if (item == null)
                         return;
@@ -102,7 +102,7 @@ public override async Task DeactivateItemAsync(T item, bool close, CancellationT
                     }
                 }
 
-                private async Task CloseItemCoreAsync(T item, CancellationToken cancellationToken)
+                private async Task CloseItemCoreAsync(T item, CancellationToken cancellationToken = default)
                 {
                     if (item.Equals(ActiveItem))
                     {
@@ -144,7 +144,7 @@ protected virtual T DetermineNextItemToActivate(IList<T> list, int lastIndex)
                 /// </summary>
                 /// <param name="cancellationToken">The cancellation token to cancel operation.</param>
                 /// <returns>A task that represents the asynchronous operation.</returns>
-                public override async Task<bool> CanCloseAsync(CancellationToken cancellationToken)
+                public override async Task<bool> CanCloseAsync(CancellationToken cancellationToken = default)
                 {
                     var closeResult = await CloseStrategy.ExecuteAsync(_items.ToList(), cancellationToken);
 

src/Caliburn.Micro.Core/DefaultCloseStrategy.cs

@@ -22,7 +22,7 @@ public DefaultCloseStrategy(bool closeConductedItemsWhenConductorCannotClose = f
         }
 
         /// <inheritdoc />
-        public async Task<ICloseResult<T>> ExecuteAsync(IEnumerable<T> toClose, CancellationToken cancellationToken)
+        public async Task<ICloseResult<T>> ExecuteAsync(IEnumerable<T> toClose, CancellationToken cancellationToken = default)
         {
             var closeable = new List<T>();
             var closeCanOccur = true;

src/Caliburn.Micro.Core/EventAggregator.cs

@@ -65,7 +65,7 @@ public virtual void Unsubscribe(object subscriber)
         }
 
         /// <inheritdoc />
-        public virtual Task PublishAsync(object message, Func<Func<Task>, Task> marshal, CancellationToken cancellationToken)
+        public virtual Task PublishAsync(object message, Func<Func<Task>, Task> marshal, CancellationToken cancellationToken = default)
         {
             if (message == null)
             {

src/Caliburn.Micro.Core/IActivate.cs

@@ -19,7 +19,7 @@ public interface IActivate
         /// </summary>
         /// <param name="cancellationToken">The cancellation token to cancel operation.</param>
         /// <returns>A task that represents the asynchronous operation.</returns>
-        Task ActivateAsync(CancellationToken cancellationToken);
+        Task ActivateAsync(CancellationToken cancellationToken = default);
 
         /// <summary>
         /// Raised after activation occurs.

src/Caliburn.Micro.Core/ICloseStrategy.cs

@@ -17,6 +17,6 @@ public interface ICloseStrategy<T>
         /// <param name="toClose">Items that are requesting close.</param>
         /// <param name="cancellationToken">The cancellation token to cancel operation.</param>
         /// <returns>A task that represents the asynchronous operation and contains the result of the strategy.</returns>
-        Task<ICloseResult<T>> ExecuteAsync(IEnumerable<T> toClose, CancellationToken cancellationToken);
+        Task<ICloseResult<T>> ExecuteAsync(IEnumerable<T> toClose, CancellationToken cancellationToken = default);
     }
 }

src/Caliburn.Micro.Core/IConductor.cs

@@ -15,7 +15,7 @@ public interface IConductor : IParent, INotifyPropertyChangedEx
         /// </summary>
         /// <param name="item">The item to activate.</param>
          /// <param name="cancellationToken">A cancellation token that can be used by other objects or threads to receive notice of cancellation.</param>
-        Task ActivateItemAsync(object item, CancellationToken cancellationToken);
+        Task ActivateItemAsync(object item, CancellationToken cancellationToken = default);
 
         /// <summary>
         /// Deactivates the specified item.
@@ -24,7 +24,7 @@ public interface IConductor : IParent, INotifyPropertyChangedEx
         /// <param name="close">Indicates whether or not to close the item after deactivating it.</param>
         /// <param name="cancellationToken">The cancellation token to cancel operation.</param>
         /// <returns>A task that represents the asynchronous operation.</returns>
-        Task DeactivateItemAsync(object item, bool close, CancellationToken cancellationToken);
+        Task DeactivateItemAsync(object item, bool close, CancellationToken cancellationToken = default);
 
         /// <summary>
         /// Occurs when an activation request is processed.

src/Caliburn.Micro.Core/IDeactivate.cs

@@ -20,7 +20,7 @@ public interface IDeactivate
         /// <param name="close">Indicates whether or not this instance is being closed.</param>
         /// <param name="cancellationToken">The cancellation token to cancel operation.</param>
         /// <returns>A task that represents the asynchronous operation.</returns>
-        Task DeactivateAsync(bool close, CancellationToken cancellationToken);
+        Task DeactivateAsync(bool close, CancellationToken cancellationToken = default);
 
         /// <summary>
         /// Raised after deactivation.

src/Caliburn.Micro.Core/IEventAggregator.cs

@@ -37,6 +37,6 @@ public interface IEventAggregator
         /// <param name = "marshal">Allows the publisher to provide a custom thread marshaller for the message publication.</param>
         /// <param name="cancellationToken">The cancellation token to cancel operation.</param>
         /// <returns>A task that represents the asynchronous operation.</returns>
-        Task PublishAsync(object message, Func<Func<Task>, Task> marshal, CancellationToken cancellationToken);
+        Task PublishAsync(object message, Func<Func<Task>, Task> marshal, CancellationToken cancellationToken = default);
     }
 }

src/Caliburn.Micro.Core/IGuardClose.cs

@@ -13,6 +13,6 @@ public interface IGuardClose : IClose
         /// </summary>
         /// <param name="cancellationToken">The cancellation token to cancel operation.</param>
         /// <returns>A task that represents the asynchronous operation and contains the result of the close.</returns>
-        Task<bool> CanCloseAsync(CancellationToken cancellationToken);
+        Task<bool> CanCloseAsync(CancellationToken cancellationToken = default);
     }
 }

src/Caliburn.Micro.Core/Screen.cs

@@ -147,7 +147,7 @@ async Task IDeactivate.DeactivateAsync(bool close, CancellationToken cancellatio
         /// </summary>
         /// <param name="cancellationToken">The cancellation token to cancel operation.</param>
         /// <returns>A task that represents the asynchronous operation and holds the value of the close check..</returns>
-        public virtual Task<bool> CanCloseAsync(CancellationToken cancellationToken)
+        public virtual Task<bool> CanCloseAsync(CancellationToken cancellationToken = default)
         {
             return Task.FromResult(true);
         }

src/Caliburn.Micro.Core/ScreenExtensions.cs

@@ -29,6 +29,17 @@ public static Task TryActivateAsync(object potentialActivatable, CancellationTok
             return potentialActivatable is IActivate activator ? activator.ActivateAsync(cancellationToken) : Task.FromResult(true);
         }
 
+        /// <summary>
+        /// Deactivates the item if it implements <see cref="IDeactivate"/>, otherwise does nothing.
+        /// </summary>
+        /// <param name="potentialDeactivatable">The potential deactivatable.</param>
+        /// <param name="close">Indicates whether or not to close the item after deactivating it.</param>
+        /// <returns>A task that represents the asynchronous operation.</returns>
+        public static Task TryDeactivateAsync(object potentialDeactivatable, bool close)
+        {
+            return potentialDeactivatable is IDeactivate deactivator ? deactivator.DeactivateAsync(close, CancellationToken.None) : Task.FromResult(true);
+        }
+
         /// <summary>
         /// Deactivates the item if it implements <see cref="IDeactivate"/>, otherwise does nothing.
         /// </summary>
@@ -41,6 +52,17 @@ public static Task TryDeactivateAsync(object potentialDeactivatable, bool close,
             return potentialDeactivatable is IDeactivate deactivator ? deactivator.DeactivateAsync(close, cancellationToken): Task.FromResult(true);
         }
 
+        /// <summary>
+        /// Closes the specified item.
+        /// </summary>
+        /// <param name="conductor">The conductor.</param>
+        /// <param name="item">The item to close.</param>
+        /// <returns>A task that represents the asynchronous operation.</returns>
+        public static Task CloseItemAsync(this IConductor conductor, object item)
+        {
+            return conductor.DeactivateItemAsync(item, true, CancellationToken.None);
+        }
+
         /// <summary>
         /// Closes the specified item.
         /// </summary>
@@ -53,6 +75,17 @@ public static Task CloseItemAsync(this IConductor conductor, object item, Cancel
             return conductor.DeactivateItemAsync(item, true, cancellationToken);
         }
 
+        /// <summary>
+        /// Closes the specified item.
+        /// </summary>
+        /// <param name="conductor">The conductor.</param>
+        /// <param name="item">The item to close.</param>
+        /// <returns>A task that represents the asynchronous operation.</returns>
+        public static Task CloseItemAsync<T>(this ConductorBase<T> conductor, T item) where T : class
+        {
+            return conductor.DeactivateItemAsync(item, true, CancellationToken.None);
+        }
+
         /// <summary>
         /// Closes the specified item.
         /// </summary>