1 files changed, 160 insertions, 0 deletions
diff --git a/Software/Visual_Studio/Tango.SharedUI/Components/LazyBinding.cs b/Software/Visual_Studio/Tango.SharedUI/Components/LazyBinding.cs
new file mode 100644
index 000000000..e8e22d182
--- /dev/null
+++ b/Software/Visual_Studio/Tango.SharedUI/Components/LazyBinding.cs
@@ -0,0 +1,160 @@
+using System;
+using System.ComponentModel;
+using System.Globalization;
+using System.Windows;
+using System.Windows.Data;
+using System.Windows.Markup;
+
+namespace Tango.SharedUI.Components
+{
+    [MarkupExtensionReturnType(typeof(object))]
+    public class LazyBindingExtension : MarkupExtension
+    {
+        public LazyBindingExtension()
+        { }
+
+        public LazyBindingExtension(PropertyPath path) : this()
+        {
+            Path = path;
+        }
+
+        #region Properties
+
+        public IValueConverter Converter { get; set; }
+        [TypeConverter(typeof(CultureInfoIetfLanguageTagConverter))]
+        public CultureInfo ConverterCulture { get; set; }
+        public object ConverterParamter { get; set; }
+        public string ElementName { get; set; }
+        [ConstructorArgument("path")]
+        public PropertyPath Path { get; set; }
+        public RelativeSource RelativeSource { get; set; }
+        public object Source { get; set; }
+        public UpdateSourceTrigger UpdateSourceTrigger { get; set; }
+        public bool ValidatesOnDataErrors { get; set; }
+        public bool ValidatesOnExceptions { get; set; }
+        public bool ValidatesOnNotifyDataErrors { get; set; }
+
+        private Binding binding;
+        private UIElement bindingTarget;
+        private DependencyProperty bindingTargetProperty;
+
+        #endregion
+
+        #region Init
+
+        public override object ProvideValue(IServiceProvider serviceProvider)
+        {
+            var valueProvider = serviceProvider.GetService(typeof(IProvideValueTarget)) as IProvideValueTarget;
+            if (valueProvider != null)
+            {
+                bindingTarget = valueProvider.TargetObject as UIElement;
+
+                if (bindingTarget == null)
+                {
+                    throw new NotSupportedException($"Target '{valueProvider.TargetObject}' is not valid for a LazyBinding. The LazyBinding target must be a UIElement.");
+                }
+
+                bindingTargetProperty = valueProvider.TargetProperty as DependencyProperty;
+
+                if (bindingTargetProperty == null)
+                {
+                    throw new NotSupportedException($"The property '{valueProvider.TargetProperty}' is not valid for a LazyBinding. The LazyBinding target property must be a DependencyProperty.");
+                }
+
+                binding = new Binding
+                {
+                    Path = Path,
+                    Converter = Converter,
+                    ConverterCulture = ConverterCulture,
+                    ConverterParameter = ConverterParamter
+                };
+
+                if (ElementName != null)
+                {
+                    binding.ElementName = ElementName;
+                }
+
+                if (RelativeSource != null)
+                {
+                    binding.RelativeSource = RelativeSource;
+                }
+
+                if (Source != null)
+                {
+                    binding.Source = Source;
+                }
+
+                binding.UpdateSourceTrigger = UpdateSourceTrigger;
+                binding.ValidatesOnDataErrors = ValidatesOnDataErrors;
+                binding.ValidatesOnExceptions = ValidatesOnExceptions;
+                binding.ValidatesOnNotifyDataErrors = ValidatesOnNotifyDataErrors;
+
+                return SetBinding();
+            }
+
+            return null;
+        }
+
+        public object SetBinding()
+        {
+            bindingTarget.IsVisibleChanged += UiElement_IsVisibleChanged;
+
+            updateBinding();
+
+            return bindingTarget.GetValue(bindingTargetProperty);
+        }
+
+        #endregion
+
+        #region Event Handlers
+
+        private void UiElement_IsVisibleChanged(object sender, DependencyPropertyChangedEventArgs e)
+        {
+            updateBinding();
+        }
+
+        #endregion
+
+        #region Update Binding
+
+        private void updateBinding()
+        {
+            if (bindingTarget.IsVisible)
+            {
+                ConsolidateBinding();
+            }
+            else
+            {
+                ClearBinding();
+            }
+        }
+
+        private bool _isBind;
+
+        private void ConsolidateBinding()
+        {
+            if (_isBind)
+            {
+                return;
+            }
+
+            _isBind = true;
+
+            BindingOperations.SetBinding(bindingTarget, bindingTargetProperty, binding);
+        }
+
+        private void ClearBinding()
+        {
+            if (!_isBind)
+            {
+                return;
+            }
+
+            BindingOperations.ClearBinding(bindingTarget, bindingTargetProperty);
+
+            _isBind = false;
+        }
+
+        #endregion
+    }
+}