c# - How to remove border from a maximized WPF window? -

i want run wpf application in fullscreen mode. used following code this project:

class winapi {     [dllimport("user32.dll", entrypoint = "getsystemmetrics")]     public static extern int getsystemmetrics(int which);      [dllimport("user32.dll")]     public static extern void         setwindowpos(intptr hwnd, intptr hwndinsertafter,                      int x, int y, int width, int height, uint flags);              private const int sm_cxscreen = 0;     private const int sm_cyscreen = 1;     private static intptr hwnd_top = intptr.zero;     private const int swp_showwindow = 64; // 0×0040      public static int screenx     {         { return getsystemmetrics(sm_cxscreen);}     }      public static int screeny     {         { return getsystemmetrics(sm_cyscreen);}     }      public static void setwinfullscreen(intptr hwnd)     {         setwindowpos(hwnd, hwnd_top, 0, 0, screenx, screeny, swp_showwindow);     } } 

in main .cs file wrote following code:

private void window1_keyup(object sender, keyeventargs e)     {          if(e.key == key.f)         {             if(!isfullscreen)             {                 height = meplayer.height;                 width = meplayer.width;                 this.borderthickness = new thickness(0.0);                 this.background = new solidcolorbrush(colors.black);                 this.windowstyle = windowstyle.none;                 this.windowstate = windowstate.maximized;                 this.topmost = true;                 winapi.setwinfullscreen(new windowinterophelper(this).handle);                 isfullscreen = !isfullscreen;             }             else             {                 this.topmost = false;                 this.background = new solidcolorbrush(colors.white);                 this.windowstyle = windowstyle.singleborderwindow;                 isfullscreen = !isfullscreen;             }         }     } 

the problem when switch fullscreen, border around window shown in screenshot below:

how remove border? issue thin dotted border around window after restore original state. how remove also?

create new wpf-application , use following code mainwindow

xaml

<window x:class="wpfapplication1.mainwindow"         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"         title="mainwindow" height="350" width="525"          keydown="keyhandler_f"         allowstransparency="true" windowstyle="none"         >     <grid>          <grid.rowdefinitions>             <rowdefinition height="200" />             <rowdefinition height="*" />         </grid.rowdefinitions>          <textblock             grid.row="0"             verticalalignment="center"             horizontalalignment="center">              press <run fontsize="60" foreground="red">f</run> toggle between fullscreen , window-screen          </textblock>          <textblock grid.row="1" margin="10" textwrapping="wrap">you need create own title-bar , minimize/ maximize/ close buttons on window seen in microsoft visual studio 2013. alternatively can create new window when switching fullscreen</textblock>      </grid> </window> 

code behind

using system; using system.collections.generic; using system.linq; using system.text; using system.threading.tasks; using system.windows; using system.windows.controls; using system.windows.data; using system.windows.documents; using system.windows.input; using system.windows.media; using system.windows.media.imaging; using system.windows.navigation; using system.windows.shapes;  namespace wpfapplication1 {     /// <summary>     /// interaction logic mainwindow.xaml     /// </summary>     public partial class mainwindow : window     {         public mainwindow()         {             initializecomponent();         }          private void button_click(object sender, routedeventargs e)         {             this.togglewindow();         }          private void keyhandler_f(object sender, keyeventargs e)         {             if(e.key == key.f)             {                 this.togglewindow();             }         }          private void togglewindow()         {             switch (this.windowstate)             {                 case (windowstate.maximized):                     {                         this.windowstate = windowstate.normal;                     }                     break;                  default:                     {                         this.windowstate = windowstate.maximized;                     }                     break;             }         }     } } 

the window behave this:

both screenshots of entire screen