Handle prop changed events to validation errors (#553)

Co-authored-by: Morten Nielsen <mort5161@esri.com>

src/Toolkit/Toolkit/UI/Controls/FeatureForm/FeatureFormView.Windows.cs

@@ -29,6 +29,23 @@ public partial class FeatureFormView : Control
         private const string ItemsViewName = "ItemsView";
         private const string FeatureFormContentScrollViewerName = "FeatureFormContentScrollViewer";
 
+        private static readonly DependencyPropertyKey IsValidPropertyKey
+          = DependencyProperty.RegisterReadOnly(nameof(IsValid), typeof(bool), typeof(FeatureFormView), new FrameworkPropertyMetadata(false));
+
+        /// <summary>
+        /// Identifies the <see cref="IsValid"/> Dependency property.
+        /// </summary>
+        public static readonly DependencyProperty IsValidProperty = IsValidPropertyKey.DependencyProperty;
+
+        /// <summary>
+        /// Gets a value indicating whether this form has any validation errors.
+        /// </summary>
+        /// <seealso cref="FeatureForm.ValidationErrors"/>
+        public bool IsValid
+        {
+            get { return (bool)GetValue(IsValidProperty); }
+            private set { SetValue(IsValidPropertyKey, value); }
+        }
     }
 }
 #endif

src/Toolkit/Toolkit/UI/Controls/FeatureForm/FeatureFormView.cs

@@ -42,6 +42,8 @@ namespace Esri.ArcGISRuntime.Toolkit.UI.Controls
     /// <seealso cref="Esri.ArcGISRuntime.Mapping.FeatureLayer.FeatureFormDefinition"/>
     public partial class FeatureFormView
     {
+        private WeakEventListener<FeatureFormView, INotifyPropertyChanged, object?, PropertyChangedEventArgs>? _elementPropertyChangedListener;
+
         /// <summary>
         /// Initializes a new instance of the <see cref="FeatureFormView"/> class.
         /// </summary>
@@ -129,27 +131,59 @@ private void InvalidateForm()
         /// </summary>
 #if MAUI
         public static readonly BindableProperty FeatureFormProperty =
-            BindableProperty.Create(nameof(FeatureForm), typeof(FeatureForm), typeof(FeatureFormView), null, propertyChanged: OnFeatureFormPropertyChanged);
+            BindableProperty.Create(nameof(FeatureForm), typeof(FeatureForm), typeof(FeatureFormView), null, propertyChanged: (s, oldValue, newValue) => ((FeatureFormView)s).OnFeatureFormPropertyChanged(oldValue, newValue));
 #else
         public static readonly DependencyProperty FeatureFormProperty =
             DependencyProperty.Register(nameof(FeatureForm), typeof(FeatureForm), typeof(FeatureFormView),
-                new PropertyMetadata(null, (s, e) => FeatureFormView.OnFeatureFormPropertyChanged(s, e.OldValue, e.NewValue)));
+                new PropertyMetadata(null, (s, e) => ((FeatureFormView)s).OnFeatureFormPropertyChanged(e.OldValue, e.NewValue)));
 #endif
 
-        private static void OnFeatureFormPropertyChanged(DependencyObject d, object oldValue, object newValue)
+        private void OnFeatureFormPropertyChanged(object oldValue, object newValue)
         {
-            var formView = (FeatureFormView)d;
             var oldForm = oldValue as FeatureForm;
             var newForm = newValue as FeatureForm;
             if (newForm is not null)
             {
-                formView.InvalidateForm();
+                InvalidateForm();
             }
 
 #if MAUI
-            (formView.GetTemplateChild(FeatureFormContentScrollViewerName) as ScrollViewer)?.ScrollToAsync(0,0,false);
+            (GetTemplateChild(FeatureFormContentScrollViewerName) as ScrollViewer)?.ScrollToAsync(0,0,false);
 #else
-            (formView.GetTemplateChild(FeatureFormContentScrollViewerName) as ScrollViewer)?.ScrollToHome();
+            (GetTemplateChild(FeatureFormContentScrollViewerName) as ScrollViewer)?.ScrollToHome();
+#endif
+
+            if (oldValue is INotifyPropertyChanged inpcOld)
+            {
+                _elementPropertyChangedListener?.Detach();
+                _elementPropertyChangedListener = null;
+            }
+            if (newValue is INotifyPropertyChanged inpcNew)
+            {
+                _elementPropertyChangedListener = new WeakEventListener<FeatureFormView, INotifyPropertyChanged, object?, PropertyChangedEventArgs>(this, inpcNew)
+                {
+                    OnEventAction = static (instance, source, eventArgs) => instance.FeatureForm_PropertyChanged(source, eventArgs),
+                    OnDetachAction = static (instance, source, weakEventListener) => source.PropertyChanged -= weakEventListener.OnEvent,
+                };
+                inpcNew.PropertyChanged += _elementPropertyChangedListener.OnEvent;
+            }
+            UpdateIsValidProperty();
+        }
+
+        private void FeatureForm_PropertyChanged(object? sender, System.ComponentModel.PropertyChangedEventArgs e)
+        {
+            if (e.PropertyName == nameof(FeatureForm.ValidationErrors))
+            {
+                UpdateIsValidProperty();
+            }
+        }
+
+        private void UpdateIsValidProperty()
+        {
+#if WPF
+            IsValid = FeatureForm?.ValidationErrors?.Any() != true;
+#elif MAUI
+#warning TODO IsValid read-only property
 #endif
         }
 

src/Toolkit/Toolkit/UI/Controls/FeatureForm/FieldFormElementView.cs

@@ -118,23 +118,6 @@ private async void OnValuePropertyChanged()
             try
             {
                 await FeatureForm.EvaluateExpressionsAsync();
-                var errors = Element.ValidationErrors;
-
-                string? errMessage = null;
-                if (errors != null && errors.Any())
-                {
-                    errMessage = string.Join("\n", errors.Select(e => FeatureFormView.ValidationErrorToLocalizedString(Element, e)!));
-                }
-                else if (Element?.IsRequired == true && (Element.Value is null || Element?.Value is string str && string.IsNullOrEmpty(str)))
-                {
-                    errMessage = "Required";
-                }
-
-                if (GetTemplateChild("ErrorLabel") is TextBlock tb)
-                {
-                    tb.Text = errMessage;
-                }
-
             }
             catch (System.Exception)
             {
@@ -157,6 +140,32 @@ private void FieldFormElement_PropertyChanged(object? sender, System.ComponentMo
                     OnValuePropertyChanged();
 #endif
             }
+            else if (e.PropertyName == nameof(FieldFormElement.ValidationErrors))
+            {
+                UpdateErrorMessages();
+            }
+        }
+
+        private void UpdateErrorMessages()
+        {
+            string? errMessage = null;
+            if (Element is not null)
+            {
+                var errors = Element.ValidationErrors;
+
+                if (errors != null && errors.Any())
+                {
+                    errMessage = string.Join("\n", errors.Select(e => FeatureFormView.ValidationErrorToLocalizedString(Element, e)!));
+                }
+                else if (Element?.IsRequired == true && (Element.Value is null || Element?.Value is string str && string.IsNullOrEmpty(str)))
+                {
+                    errMessage = Properties.Resources.GetString("FeatureFormFieldIsRequired");
+                }
+            }
+            if (GetTemplateChild("ErrorLabel") is TextBlock tb)
+            {
+                tb.Text = errMessage;
+            }
         }
     }
 }

src/Toolkit/Toolkit/UI/Controls/FeatureForm/TextFormInputView.cs

@@ -53,6 +53,7 @@ public override void OnApplyTemplate()
                 barcodeButton.Click += BarcodeButton_Click;
 #endif
             }
+            UpdateValidationState();
         }
 
         private void BarcodeButton_Click(object sender, RoutedEventArgs e)
@@ -133,21 +134,11 @@ private void Apply()
                 value = datevalue;
             try
             {
-                Element?.UpdateValue(value); // Throws FeatureFormIncorrectValueTypeException if type is incorrect instead of populating ValidationErrors IssueRef:apollo#456
+                Element?.UpdateValue(value);
             }
-            catch (System.Exception)
+            catch (System.Exception) // Unexpected error setting value
             {
                 _textInput.Text = Element?.Value?.ToString();  //Reset input to previous valid value
-                return;
-            }
-            var err = Element?.ValidationErrors;
-            if (err != null && err.Any())
-            {
-                VisualStateManager.GoToState(this, "InputError", true);
-            }
-            else
-            {
-                VisualStateManager.GoToState(this, "InputValid", true);
             }
         }
 
@@ -164,7 +155,7 @@ public int MinLines
         /// Identifies the <see cref="MinLines"/> dependency property.
         /// </summary>
         public static readonly DependencyProperty MinLinesProperty = 
-            DependencyProperty.Register("MinLines", typeof(int), typeof(TextFormInputView), new PropertyMetadata(1));
+            DependencyProperty.Register(nameof(MinLines), typeof(int), typeof(TextFormInputView), new PropertyMetadata(1));
 
         /// <summary>
         /// Gets or sets the maximum number of visible lines.
@@ -254,6 +245,26 @@ private void Element_PropertyChanged(object? sender, System.ComponentModel.Prope
                 else 
                     Dispatcher.Invoke(ConfigureTextBox);
             }
+            else if (e.PropertyName == nameof(FieldFormElement.ValidationErrors))
+            {
+                if (Dispatcher.CheckAccess())
+                    UpdateValidationState();
+                else
+                    Dispatcher.Invoke(UpdateValidationState);
+            }
+        }
+
+        private void UpdateValidationState()
+        {
+            var err = Element?.ValidationErrors;
+            if (err != null && err.Any())
+            {
+                VisualStateManager.GoToState(this, "InputError", true);
+            }
+            else
+            {
+                VisualStateManager.GoToState(this, "InputValid", true);
+            }
         }
     }
 }