Updates for 4.7.

Author: davidbritch

DataBindingDemos/DataBindingDemos/DataBindingDemos/Converters/StringConcatenationConverter.cs

@@ -34,7 +34,7 @@ public object Convert(object[] values, Type targetType, object parameter, Cultur
                 {
                     return BindableProperty.UnsetValue;
                 }
-                if (value as string == "null")
+                if (value as string == null)
                 {
                     return null;
                 }
@@ -68,7 +68,7 @@ public object[] ConvertBack(object value, Type[] targetTypes, object parameter,
             for (int i = 0; i < array.Length; i++)
             {
                 var str = array[i] as string;
-                if (str == "null")
+                if (str == null)
                 {
                     array[i] = null;
                 }                    

DataBindingDemos/DataBindingDemos/DataBindingDemos/Views/MultiBindingFallbackValuePage.xaml

@@ -18,6 +18,7 @@
         <Label>
             <Label.Text>
                 <MultiBinding FallbackValue="Name unavailable"
+                              TargetNullValue="Data unavailable"
                               Converter="{StaticResource StringConcatConverter}">
                     <Binding Path="Employee1.Forename" />
                     <Binding Path="Employee1.MiddleName" />
@@ -30,6 +31,7 @@
                 <!-- This MultiBinding should return its FallbackValue,
                      because the converter returns BindableProperty.UnsetValue -->
                 <MultiBinding FallbackValue="Name unavailable"
+                              TargetNullValue="Data unavailable"
                               Converter="{StaticResource StringConcatConverter}">
                     <Binding Path="Employee.Forename" />
                     <Binding Path="Employee.MiddleName" />
@@ -40,6 +42,7 @@
         <Label>
             <Label.Text>
                 <MultiBinding FallbackValue="Name unavailable"
+                              TargetNullValue="Data unavailable"
                               Converter="{StaticResource StringConcatConverter}">
                     <Binding Path="Employee3.Forename" />
                     <Binding Path="Employee3.MiddleName" />
@@ -50,6 +53,7 @@
         <Label>
             <Label.Text>
                 <MultiBinding FallbackValue="Name unavailable"
+                              TargetNullValue="Data unavailable"
                               Converter="{StaticResource StringConcatConverter}">
                     <Binding Path="Employee4.Forename" />
                     <Binding Path="Employee4.MiddleName" />
@@ -60,6 +64,7 @@
         <Label>
             <Label.Text>
                 <MultiBinding FallbackValue="Name unavailable"
+                              TargetNullValue="Data unavailable"
                               Converter="{StaticResource StringConcatConverter}">
                     <Binding Path="Employee5.Forename" />
                     <Binding Path="Employee5.MiddleName" />
@@ -72,6 +77,7 @@
                 <!-- This MultiBinding should return its FallbackValue,
                      because the converter returns BindableProperty.UnsetValue -->
                 <MultiBinding FallbackValue="Name unavailable"
+                              TargetNullValue="Data unavailable"
                               Converter="{StaticResource StringConcatConverter}">
                     <Binding Path="Employee6.Forename" />
                     <Binding Path="Employee6.MiddleName" />