reafactor out _suggestionRequestedCancellationSource

Author: huynhsontung

Microsoft.Toolkit.Uwp.UI.Controls.Input/RichSuggestBox/RichSuggestBox.Helpers.cs

@@ -104,22 +104,5 @@ private static void ForEachLinkInDocument(ITextDocument document, Action<ITextRa
                 nextIndex = range.GetIndex(TextRangeUnit.Link);
             }
         }
-
-        private static void CancelIfNotDisposed(CancellationTokenSource cancellationSource)
-        {
-            if (cancellationSource == null || cancellationSource.IsCancellationRequested)
-            {
-                return;
-            }
-
-            try
-            {
-                cancellationSource.Cancel();
-            }
-            catch (ObjectDisposedException)
-            {
-                // pass
-            }
-        }
     }
 }

Microsoft.Toolkit.Uwp.UI.Controls.Input/RichSuggestBox/RichSuggestBox.cs

@@ -55,7 +55,6 @@ public partial class RichSuggestBox : ItemsControl
         private bool _popupOpenDown;
         private bool _textCompositionActive;
         private RichSuggestQuery _currentQuery;
-        private CancellationTokenSource _suggestionRequestedCancellationSource;
 
         /// <summary>
         /// Initializes a new instance of the <see cref="RichSuggestBox"/> class.
@@ -534,17 +533,25 @@ private async Task RequestSuggestionsAsync(ITextRange range = null)
                 return;
             }
 
-            CancelIfNotDisposed(this._suggestionRequestedCancellationSource);
-            this._suggestionRequestedCancellationSource = null;
+            var previousTokenSource = currentQuery?.CancellationTokenSource;
+            if (!(previousTokenSource?.IsCancellationRequested ?? true))
+            {
+                previousTokenSource.Cancel();
+            }
 
             if (queryFound)
             {
-                _currentQuery = new RichSuggestQuery { Prefix = prefix, QueryText = query, Range = range };
+                using var tokenSource = new CancellationTokenSource();
+                _currentQuery = new RichSuggestQuery
+                {
+                    Prefix = prefix,
+                    QueryText = query,
+                    Range = range,
+                    CancellationTokenSource = tokenSource
+                };
 
                 if (SuggestionsRequested != null)
                 {
-                    using var tokenSource = new CancellationTokenSource();
-                    _suggestionRequestedCancellationSource = tokenSource;
                     var cancellationToken = tokenSource.Token;
                     var eventArgs = new SuggestionsRequestedEventArgs { QueryText = query, Prefix = prefix };
                     try
@@ -562,6 +569,8 @@ private async Task RequestSuggestionsAsync(ITextRange range = null)
                         ShowSuggestionsPopup(_suggestionsList?.Items?.Count > 0);
                     }
                 }
+
+                tokenSource.Cancel();
             }
             else
             {

Microsoft.Toolkit.Uwp.UI.Controls.Input/RichSuggestBox/RichSuggestQuery.cs

@@ -2,6 +2,7 @@
 // The .NET Foundation licenses this file to you under the MIT license.
 // See the LICENSE file in the project root for more information.
 
+using System.Threading;
 using Windows.UI.Text;
 
 namespace Microsoft.Toolkit.Uwp.UI.Controls
@@ -16,5 +17,7 @@ internal class RichSuggestQuery
         public string QueryText { get; set; }
 
         public ITextRange Range { get; set; }
+
+        public CancellationTokenSource CancellationTokenSource { get; set; }
     }
 }