WPF and Visual Studio

WPF: Using VS, we can  create 2 kinds of WPF applications, one is desktop application " WPF Application" another is Web RIA application " WPF Browser Application";
VS: An IDE;
Create a WPF "Hello world" Application:
        File -> New project -> WPF Application;  (HelloWorld)

     We can see the auto-create file at the VS right panel Solution Explorer, where display all files of our project; And we should know the usage of each file and folder:   
  Properties folder contain and properties of project; we can add new resource from here;
     Reference folder contain some libs for running project;
     app.config is configurations file;
     app.xaml is whole layout setting, the Application will load this file at first;
<Application x:Class="HelloWorld.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             StartupUri="MainWindow.xaml">           // When app is loading, MainWindow will be start;
    <Application.Resources>
</Application.Resources>
</Application>
       In this files tree, every instance of window have a branch like MainWindow;  And xaml file is layout file, corresponding cs file is C# file which will respond to all requests and events sent from window；
       When we create a new window, we can use grid to set layout;  
       We need to write much C# code to deal with the event; WPF offer some basic event, to which we can depart some complex event;
       Mｙ　Ｅｘａｍｐｌｅ:
Create a new WPF　Ａｐｐ，C_SMS,
First thing we need to set the most top Grid, to build a nice frame to display your layout; you can design your Grid at UI design view, it's very easy and  intuitive to make it out;
now, you have an static UI，what you need to do just add some events; there are a simple way to implement Dragging control;  right click "solution explorer" to add reference, and find two lib files:
"Microsoft.Expression.Interactions.dll"
"System.Windows.Interactivity.dll"
from MS expression blend 4
then add below to MainWindow.xaml
xmlns:i="http://schemas.microsoft.com/expression/2010/interactivity"
        xmlns:b="http://schemas.microsoft.com/expression/2010/interactions"
add below to control which you want to drag it
                <i:Interaction.Behaviors>
                    <b:MouseDragElementBehavior Dragging="" DragFinished=""/>
                </i:Interaction.Behaviors>
We should write C# function to deal with events Dragging and DragFinished;