Merge pull request #2534 from cwensley/curtis/wpf-fix-slow-textbox-te…

…xt-updates Wpf: Fix performance setting TextBox.Text rapidly
picoe · Jul 26, 2023 · a7b303d · a7b303d
2 parents 193de2d + fa3fbce
commit a7b303d
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diff --git a/src/Eto.Wpf/Forms/Controls/TextBoxHandler.cs b/src/Eto.Wpf/Forms/Controls/TextBoxHandler.cs
@@ -1,3 +1,4 @@
+using System.Runtime;
 using swd = System.Windows.Documents;
 namespace Eto.Wpf.Forms.Controls
 {
@@ -16,6 +17,14 @@ public class TextBoxHandler : TextBoxHandler<xwt.WatermarkTextBox, TextBox, Text
 		internal static object CurrentText_Key = new object();
 		internal static object CurrentSelection_Key = new object();
 		internal static object DisableTextChanged_Key = new object();
+		internal static object EnableNoGCRegion_Key = new object();
+
+		/// <summary>
+		/// Gets or sets the default value indicating to use GC.TryStartNoGCRegion() when setting TextBox.Text
+		/// to avoid performance issues with WPF.
+		/// See https://github.com/dotnet/wpf/issues/5887
+		/// </summary>
+		public static bool EnableNoGCRegionDefault = true;
 
 		protected override swc.TextBox TextBox => Control;
 
@@ -58,6 +67,18 @@ public override bool ShowBorder
 			}
 		}
 
+		/// <summary>
+		/// Gets or sets a value indicating to use GC.TryStartNoGCRegion() when setting TextBox.Text
+		/// to avoid performance issues with WPF.
+		/// See https://github.com/dotnet/wpf/issues/5887
+		/// </summary>
+		/// <seealso cref="TextBoxHandler.EnableNoGCRegionDefault" />
+		public bool EnableNoGCRegion
+		{
+			get => Widget.Properties.Get<bool?>(TextBoxHandler.EnableNoGCRegion_Key) ?? TextBoxHandler.EnableNoGCRegionDefault;
+			set => Widget.Properties.Set(TextBoxHandler.EnableNoGCRegion_Key, value);
+		}
+
 		public TextAlignment TextAlignment
 		{
 			get { return TextBox.TextAlignment.ToEto(); }
@@ -285,7 +306,17 @@ public string Text
 					if (args.Cancel)
 						return;
 					var needsTextChanged = TextBox.Text == newText;
+
+					// Improve performance when setting text often
+					// See https://github.com/dotnet/wpf/issues/5887#issuecomment-1604577981
+					if (EnableNoGCRegion)
+						GC.TryStartNoGCRegion(1000000); // is this magic number reasonable??
+
 					TextBox.Text = newText;
+
+					if (EnableNoGCRegion && GCSettings.LatencyMode == GCLatencyMode.NoGCRegion)
+						GC.EndNoGCRegion();
+
 					if (needsTextChanged)
 					{
 						Callback.OnTextChanged(Widget, EventArgs.Empty);

diff --git a/test/Eto.Test/UnitTests/Forms/Controls/TextBoxTests.cs b/test/Eto.Test/UnitTests/Forms/Controls/TextBoxTests.cs
@@ -192,6 +192,55 @@ public void InsertingTextShouldFireTextChanging(string oldText, string newText,
 			Assert.AreEqual(text, args.Text, "#2.4");
 			Assert.AreEqual(Range.FromLength(rangeStart, rangeLength), args.Range, "#2.5");
 		}
+
+		[Test, ManualTest]
+		public void ManyUpdatesShouldNotCauseHangs()
+		{	
+			TimeSpan maxElapsed = TimeSpan.MinValue;
+			ManualForm(
+			"There should not be any pausing",
+			form =>
+			{
+				var textBoxes = new List<T>();
+				var layout = new DynamicLayout();
+				for (int x = 0; x < 10; x++)
+				{
+					layout.BeginHorizontal();
+					for (int y = 0; y < 10; y++)
+					{
+						var textBox = new T();
+						textBoxes.Add(textBox);
+						layout.Add(textBox, true);
+					}
+					layout.EndHorizontal();
+				}
+				var sw = new Stopwatch();
+				var timer = new UITimer { Interval = 0.01 };
+				timer.Elapsed += (sender, e) =>
+				{
+					var elapsed = sw.Elapsed;
+					if (elapsed > maxElapsed)
+					{
+						maxElapsed = elapsed;
+					}
+					sw.Restart();
+					var rnd = new Random();
+					foreach (var tb in textBoxes)
+					{
+						tb.Text = rnd.Next(int.MaxValue).ToString();
+					}
+				};
+				form.Shown += (sender, e) =>
+				{
+					timer.Start();
+					sw.Start();
+				};
+				form.Closed += (sender, e) => timer.Stop();
+
+				return layout;
+			});
+			Assert.Less(maxElapsed, TimeSpan.FromSeconds(1), "There were long pauses in the UI");
+		}
 	}