fix(textbox): A binding on the TextBox.Text property were always tr…

…eated as a `TwoWay` binding.

Fix #3522

src/SamplesApp/SamplesApp.Shared/App.xaml.cs

@@ -238,13 +238,14 @@ private void InitializeFrame(string arguments = null)
 				// When the navigation stack isn't restored navigate to the first page,
 				// configuring the new page by passing required information as a navigation
 				// parameter
+				var startingPageType = typeof(MainPage);
 				if (arguments != null)
 				{
-					rootFrame.Navigate(typeof(MainPage), arguments);
+					rootFrame.Navigate(startingPageType, arguments);
 				}
 				else
 				{
-					rootFrame.Navigate(typeof(MainPage));
+					rootFrame.Navigate(startingPageType);
 				}
 			}
 		}

src/SamplesApp/SamplesApp.UITests/Windows_UI_Xaml_Controls/TextBoxTests/TextBoxTests.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Drawing;
 using System.Linq;
+using System.Threading;
 using System.Threading.Tasks;
 using FluentAssertions;
 using FluentAssertions.Execution;
@@ -39,6 +40,44 @@ public void TextBox_NaturalSize_When_Empty_Is_Right_XPos()
 			sut.X.Should().Be(recth.X, "Invalid X position");
 		}
 
+		[Test]
+		[AutoRetry]
+		public void TextBox_UpdatedBinding_On_OneWay_Mode()
+		{
+			Run("UITests.Windows_UI_Xaml_Controls.TextBox.TextBox_Bindings");
+
+			var textboxTwoWay = _app.Marked("textboxTwoWay");
+			var textboxOneWay = _app.Marked("textboxOneWay");
+			var textboxDefault = _app.Marked("textboxDefault");
+
+			var textblock = _app.Marked("textblock");
+
+			// Initial situation
+			textblock.GetDependencyPropertyValue("Text").Should().Be("", "Initial should be empty");
+
+			// Enter text in two-way text
+			textboxTwoWay.EnterText("TwoWay Content");
+			textboxOneWay.FastTap();
+
+			_app.WaitForText(textblock, "TwoWay Content");
+
+			// Enter text in one-way text
+			textboxOneWay.EnterText("OneWay Content");
+			textboxDefault.FastTap();
+
+			// Ensure bound valud didn't change
+			Thread.Sleep(120);
+			_app.WaitForText(textblock, "TwoWay Content");
+
+			// Enter text in one-way text
+			textboxDefault.EnterText("Default Content");
+			textboxTwoWay.FastTap();
+
+			// Ensure bound valud didn't change
+			Thread.Sleep(120);
+			_app.WaitForText(textblock, "TwoWay Content");
+		}
+
 		[Test]
 		[AutoRetry]
 		public void TextBox_Foreground()

src/SamplesApp/UITests.Shared/UITests.Shared.projitems

@@ -1045,6 +1045,10 @@
       <SubType>Designer</SubType>
       <Generator>MSBuild:Compile</Generator>
     </Page>
+    <Page Include="$(MSBuildThisFileDirectory)Windows_UI_Xaml_Controls\TextBox\TextBox_Bindings.xaml">
+      <SubType>Designer</SubType>
+      <Generator>MSBuild:Compile</Generator>
+    </Page>
     <Page Include="$(MSBuildThisFileDirectory)Windows_UI_Xaml_Controls\TextBox\TextBox_Binding_Null.xaml">
       <SubType>Designer</SubType>
       <Generator>MSBuild:Compile</Generator>
@@ -4022,6 +4026,9 @@
     <Compile Include="$(MSBuildThisFileDirectory)Windows_UI_Xaml_Controls\TextBox\TextBox_BeforeTextChanging.xaml.cs">
       <DependentUpon>TextBox_BeforeTextChanging.xaml</DependentUpon>
     </Compile>
+    <Compile Include="$(MSBuildThisFileDirectory)Windows_UI_Xaml_Controls\TextBox\TextBox_Bindings.xaml.cs">
+      <DependentUpon>TextBox_Bindings.xaml</DependentUpon>
+    </Compile>
     <Compile Include="$(MSBuildThisFileDirectory)Windows_UI_Xaml_Controls\TextBox\TextBox_Binding_Null.xaml.cs">
       <DependentUpon>TextBox_Binding_Null.xaml</DependentUpon>
     </Compile>

src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/TextBox/TextBox_Bindings.xaml

@@ -0,0 +1,20 @@
+<Page
+	x:Class="UITests.Windows_UI_Xaml_Controls.TextBox.TextBox_Bindings"
+	xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+	xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+	xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+	xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+	mc:Ignorable="d"
+	Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
+
+	<StackPanel Spacing="10" MaxWidth="275" Margin="20">
+		<TextBlock FontSize="18">TextBox bound with TwoWay mode</TextBlock>
+		<TextBox Text="{Binding Text, Mode=TwoWay}" x:Name="textboxTwoWay" />
+		<TextBlock FontSize="18">TextBox bound with OneWay mode</TextBlock>
+		<TextBox Text="{Binding Text, Mode=OneWay}" x:Name="textboxOneWay" />
+		<TextBlock FontSize="18">TextBox bound with default mode (OneWay)</TextBlock>
+		<TextBox Text="{Binding Text}" x:Name="textboxDefault" />
+		<TextBlock FontSize="18">TextBlock bound on same content</TextBlock>
+		<TextBlock Text="{Binding Text}" x:Name="textblock" />
+	</StackPanel>
+</Page>

src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/TextBox/TextBox_Bindings.xaml.cs

@@ -0,0 +1,35 @@
+using System.ComponentModel;
+using Windows.UI.Xaml.Controls;
+using Uno.UI.Samples.Controls;
+
+namespace UITests.Windows_UI_Xaml_Controls.TextBox
+{
+	[Sample(IgnoreInSnapshotTests=true)]
+	public sealed partial class TextBox_Bindings : Page
+	{
+		public TextBox_Bindings()
+		{
+			this.InitializeComponent();
+			DataContext = new TextBox_Bindings_Context();
+		}
+
+	}
+
+	[Windows.UI.Xaml.Data.Bindable]
+	internal class TextBox_Bindings_Context : INotifyPropertyChanged
+	{
+		private string _text;
+
+		public string Text
+		{
+			get => _text;
+			set
+			{
+				_text = value;
+				PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Text)));
+			}
+		}
+
+		public event PropertyChangedEventHandler PropertyChanged;
+	}
+}

src/Uno.UI/DataBinding/BindingExpression.cs

@@ -155,6 +155,9 @@ public void UpdateSource()
 		/// <summary>
 		/// Sends the current binding target value to the binding source property in TwoWay bindings.
 		/// </summary>
+		/// <remarks>
+		/// This method is not part of UWP contract
+		/// </remarks>
 		/// <param name="value">The expected current value of the target</param>
 		public void UpdateSource(object value)
 		{
@@ -163,6 +166,13 @@ public void UpdateSource(object value)
 				return;
 			}
 
+			if (ParentBinding.Mode != BindingMode.TwoWay)
+			{
+				// Calling this method does nothing if the Mode value of the binding is not TwoWay.
+				// [Microsoft documentation https://docs.microsoft.com/en-us/uwp/api/windows.ui.xaml.data.bindingexpression.updatesource#remarks]
+				return;
+			}
+
 #if !HAS_EXPENSIVE_TRYFINALLY // Try/finally incurs a very large performance hit in mono-wasm - https://github.com/mono/mono/issues/13653
 			try
 #endif

src/Uno.UI/UI/Xaml/Data/UpdateSourceTrigger.cs

@@ -1,29 +1,29 @@
 using Uno;
 
-namespace Windows.UI.Xaml.Data
-{
-	/// <summary>
-	/// Defines constants that indicate when a binding source is updated by its binding target in two-way binding.
-	/// </summary>
-	public enum UpdateSourceTrigger
-	{
-		/// <summary>
-		/// Use default behavior from the dependency property that uses the binding. In Windows Runtime, this evaluates the same as a value with PropertyChanged.
-		/// </summary>
-		Default = 0,
-		/// <summary>
-		/// The binding source is updated whenever the binding target value changes. This is detected automatically by the binding system.
-		/// </summary>
-		PropertyChanged = 1,
-		/// <summary>
-		/// The binding source is updated only when you call the BindingExpression.UpdateSource method.
-		/// </summary>
+namespace Windows.UI.Xaml.Data
+{
+	/// <summary>
+	/// Defines constants that indicate when a binding source is updated by its binding target in two-way binding.
+	/// </summary>
+	public enum UpdateSourceTrigger
+	{
+		/// <summary>
+		/// Use default behavior from the dependency property that uses the binding. In Windows Runtime, this evaluates the same as a value with PropertyChanged.
+		/// </summary>
+		Default = 0,
+		/// <summary>
+		/// The binding source is updated whenever the binding target value changes. This is detected automatically by the binding system.
+		/// </summary>
+		PropertyChanged = 1,
+		/// <summary>
+		/// The binding source is updated only when you call the BindingExpression.UpdateSource method.
+		/// </summary>
 		Explicit = 2,
 		/// <summary>	
 		/// The binding source is updated whenever the binding target element loses focus.
-		/// </summary>
-		[NotImplemented]
-		LostFocus = 3,
-	}
-}
-
+		/// </summary>
+		[NotImplemented]
+		LostFocus = 3,
+	}
+}
+