Rename .NET folder to DotNet

DotNet/Xamarin/App.xaml.md

@@ -0,0 +1,51 @@
+# App.xaml
+
+## Root Tag
+
+The `<Application>` tag begins with two XML namespace declarations, both of which are URIs.
+
+The default namespace belongs to **Xamarin**. This is the XML namespace (`xmlns`) for elements in the file with no prefix, such as the `ContentPage` tag.
+The URI includes the year that this namespace came into being and the word *forms* as an abbreviation for Xamarin.Forms.
+
+The second namespace is associated with a prefix of `x` by convention, and it belongs to **Microsoft**. This namespace refers to elements and attributes that are intrinsic to XAML and are found in every XAML implementation.
+The word *winfx* refers to a name once used for the .NET Framework 3.0, which introduced WPF and XAML.
+
+The `x:Class` attribute can appear only on the root element of a XAML file. It specifies the .NET namespace and name of a derived class. The base class of this derived class is the root element.
+
+In other words, this `x:Class` specification indicates that the `App` class in the `AppName` namespace derives from `Application`.
+That’s exactly the same information as the `App` class definition in the `App.xaml.cs` file.
+
+```xml
+<?xml version="1.0" encoding="utf-8" ?>
+<Application xmlns="http://xamarin.com/schemas/2014/forms"
+             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+             x:Class="AppName.App">
+</Application>
+```
+
+## Shared Resources
+
+```xml
+<?xml version="1.0" encoding="utf-8" ?>
+<Application xmlns="http://xamarin.com/schemas/2014/forms"
+             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+             x:Class="AppName.App">
+
+    <!-- collection of shared resources definiions -->
+    <Application.Resources>
+
+        <!-- Application resource dictionary -->
+        <ResourceDictionary>
+            <!-- Key-Value Pair -->
+            <Type x:Key="DictKey">value<Type>
+        </ResourceDictionary>
+
+        <!-- define a reusable style -->
+        <Style x:Key="Style Name" TargetType="Element Type">
+            <!-- set poperties of the style -->
+            <Setter Property="PropertyName" Value="PropertyValue">
+        </Style>
+
+    </Application.Resources>
+</Application>
+```