Gets or sets a value indicating the number of characters in the current selection in the text box.
Assembly: PresentationFramework (in PresentationFramework.dll)
XMLNS for XAML: http://schemas.microsoft.com/winfx/2006/xaml/presentation, http://schemas.microsoft.com/netfx/2007/xaml/presentation
Getting this property returns the number of characters in the current selection. Setting this property adjusts the length of the current selection to the specified value, keeping the beginning of the selection fixed.
In general, when the specified selection length causes the selection to end in an invalid position (for example, between a carriage return and a new-line character, or inside a tag), the selection length automatically adjusts so that the resulting selection starts and ends in valid positions.