Deprecate CanClose

There's no nice way to make it work alongside CanCloseAsync when you're
in a conductor hierarchy. There will always be difference between how
CanClose and CanCloseAsync behave when there are children which need
to be interrogated as well, and that's confusing.

Stylet/Conductor.cs

@@ -56,7 +56,10 @@ namespace Stylet
         /// <returns>Task indicating whether this can be closed</returns>
         public override Task<bool> CanCloseAsync()
         {
+            // Temporarily, until we remove CanClose
+#pragma warning disable CS0618 // Type or member is obsolete
             if (!this.CanClose())
+#pragma warning restore CS0618 // Type or member is obsolete
                 return Task.FromResult(false);
             return this.CanCloseItem(this.ActiveItem);
         }

Stylet/ConductorAllActive.cs

@@ -122,7 +122,10 @@ namespace Stylet
                 /// <returns>A Task indicating whether this conductor can close</returns>
                 public override Task<bool> CanCloseAsync()
                 {
+                    // Temporarily, until we remove CanClose
+#pragma warning disable CS0618 // Type or member is obsolete
                     if (!this.CanClose())
+#pragma warning restore CS0618 // Type or member is obsolete
                         return Task.FromResult(false);
                     return this.CanAllItemsCloseAsync(this.items);
                 }

Stylet/ConductorNavigating.cs

@@ -92,7 +92,10 @@ namespace Stylet
             /// <returns>A task indicating whether this conductor can close</returns>
             public override Task<bool> CanCloseAsync()
             {
+                // Temporarily, until we remove CanClose
+#pragma warning disable CS0618 // Type or member is obsolete
                 if (!this.CanClose())
+#pragma warning restore CS0618 // Type or member is obsolete
                     return Task.FromResult(false);
                 return this.CanAllItemsCloseAsync(this.history.Concat(new[] { this.ActiveItem }));
             }

Stylet/ConductorOneActive.cs

@@ -170,7 +170,10 @@ namespace Stylet
                 /// <returns>A task indicating whether this conductor can close</returns>
                 public override Task<bool> CanCloseAsync()
                 {
+                    // Temporarily, until we remove CanClose
+#pragma warning disable CS0618 // Type or member is obsolete
                     if (!this.CanClose())
+#pragma warning restore CS0618 // Type or member is obsolete
                         return Task.FromResult(false);
                     return this.CanAllItemsCloseAsync(this.items);
                 }

Stylet/Screen.cs

@@ -257,13 +257,17 @@ namespace Stylet
         /// <returns>A task returning true (can close) or false (can't close)</returns>
         public virtual Task<bool> CanCloseAsync()
         {
+            // Temporary, before we remove CanClose()
+#pragma warning disable CS0618 // Type or member is obsolete
             return Task.FromResult(this.CanClose());
+#pragma warning restore CS0618 // Type or member is obsolete
         }
 
         /// <summary>
         /// Synchronous alternative to CanClose
         /// </summary>
         /// <returns>True if this screen can close, or false otherwise</returns>
+        [Obsolete("This method is deprecated, please use CanCloseAsync() instead")]
         protected virtual bool CanClose()
         {
             return true; 

StyletUnitTests/ConductorAllActiveTests.cs

@@ -15,9 +15,9 @@ namespace StyletUnitTests
         private class MyConductor : Conductor<IScreen>.Collection.AllActive
         {
             public bool CanCloseValue = true;
-            protected override bool CanClose()
+            public override async Task<bool> CanCloseAsync()
             {
-                return this.CanCloseValue;
+                return this.CanCloseValue && await base.CanCloseAsync();
             }
         }
 

StyletUnitTests/ConductorNavigatingTests.cs

@@ -15,9 +15,9 @@ namespace StyletUnitTests
         private class MyConductor : Conductor<IScreen>.StackNavigation
         {
             public bool CanCloseValue = true;
-            protected override bool CanClose()
+            public override async Task<bool> CanCloseAsync()
             {
-                return this.CanCloseValue;
+                return this.CanCloseValue && await base.CanCloseAsync();
             }
         }
 

StyletUnitTests/ConductorOneActiveTests.cs

@@ -15,9 +15,9 @@ namespace StyletUnitTests
         private class MyConductor : Conductor<IScreen>.Collection.OneActive
         {
             public bool CanCloseValue = true;
-            protected override bool CanClose()
+            public override async Task<bool> CanCloseAsync()
             {
-                return this.CanCloseValue;
+                return this.CanCloseValue && await base.CanCloseAsync();
             }
         }
 

StyletUnitTests/ConductorTests.cs

@@ -15,9 +15,9 @@ namespace StyletUnitTests
         private class MyConductor : Conductor<IScreen>
         {
             public bool CanCloseValue = true;
-            protected override bool CanClose()
+            public async override Task<bool> CanCloseAsync()
             {
-                return this.CanCloseValue;
+                return this.CanCloseValue && await base.CanCloseAsync();
             }
         }
 

StyletUnitTests/ScreenTests.cs

@@ -3,6 +3,7 @@ using NUnit.Framework;
 using Stylet;
 using System;
 using System.Collections.Generic;
+using System.Threading.Tasks;
 using System.Windows;
 
 namespace StyletUnitTests
@@ -65,9 +66,9 @@ namespace StyletUnitTests
             }
 
             public bool? CanCloseResult = null;
-            protected override bool CanClose()
+            public override Task<bool> CanCloseAsync()
             {
-                return this.CanCloseResult == null ? base.CanClose() : this.CanCloseResult.Value;
+                return this.CanCloseResult == null ? base.CanCloseAsync() : Task.FromResult(this.CanCloseResult.Value);
             }
         }