How to make full screen mode, without covering the taskbar using :wpf c#

You may try this:

MaxHeight = SystemParameters.MaximizedPrimaryScreenHeight;
MaxWidth = SystemParameters.MaximizedPrimaryScreenWidth;

Found a solution on CodeProject which may help: http://www.codeproject.com/Articles/107994/Taskbar-with-Window-Maximized-and-WindowState-to-N

WindowStyle="None"
WindowState="Maximized"
ResizeMode="NoResize"

and

this.Width = System.Windows.Forms.Screen.PrimaryScreen.WorkingArea.Width;
this.Height = System.Windows.Forms.Screen.PrimaryScreen.WorkingArea.Height;
this.Left = 0;
this.Top = 0;
this.WindowState = WindowState.Normal;

WindowStyle="None" 
AllowsTransparency="True"  

and

this.Top = 0;
this.Left = 0;
this.Width = SystemParameters.WorkArea.Width;
this.Height = SystemParameters.WorkArea.Height;