Single instance application in wpf
What is single instance application:
Only one instance of the application runs once at a time on a single machine.
Need of single instance application:
If your application is so heavy and takes lots of system resources, and running multiple instance is not required, preventing users to run only one instance of the application [...]

Opening wpf window in desing mode in visual studio is not often desired. Visual studio doesnot have much tools to edit xaml in design mode. So most developers doesnot want wpf window by default in visual studio, but visual studio by default opens wpf window both in desing mode and xaml mode(splited window).
Opening in only [...]

ListCollectionView can be used to sort listbox in wpf.
Create ListCollectionView instance providing the list collection.

var view = new ListCollectionView((IList)data);

listbox.DataContext = view;

In the button click event you can add instance of SortDescription to which column and direction you wish to sort the view. Since listbox is bound to the ListCollectionView , sorting ListCollectionView also sorts the [...]

WPF exists as a subset of .NET Framework types that are for the most part located in the System.Windows namespace. If you have previously built applications with .NET Framework using managed technologies like ASP.NET and Windows Forms, the fundamental WPF programming experience should be familiar.
XAML:
XAML is a markup language ued to construct layout in Windows [...]

Microsoft .NET Framework is an integral Windows component that supports building and running the next generation of applications and Web services. The key components of the .NET Framework are the common language runtime (CLR) and the .NET Framework class library, which includes ADO.NET, ASP.NET, Windows Forms, and Windows Presentation Foundation (WPF). The .NET Framework provides [...]