c# - make GlobalKeyboardHook class read string comes from 2D barcode scanner -

i using globalkeyboardhook class make application listen keyboard keydown event , works fine when barcode scanner scan image, return string "dos-720" encodeing "ÃÍãÏ", globalkeyboardhook class return thing "¤aii¤",

how make globalkeyboardhook class return original string??

the globalkeyboardhook class

  public class globalkeyboardhook {     [dllimport("user32.dll")]     private static extern int callnexthookex(intptr hhk, int code, int wparam, ref keyboardhookstruct lparam);      [dllimport("user32.dll")]     private static extern intptr setwindowshookex(int idhook, llkeyboardhook callback, intptr hinstance,                                                   uint theardid);      [dllimport("user32.dll")]     private static extern bool unhookwindowshookex(intptr hinstance);      [dllimport("kernel32.dll")]     private static extern intptr loadlibrary(string lpfilename);      public delegate int llkeyboardhook(int code, int wparam, ref keyboardhookstruct lparam);      public struct keyboardhookstruct     {         public int vkcode;         public int scancode;         public int flags;         public int time;         public int dwextrainfo;     }      private const int wh_keyboard_ll = 13;     private const int wm_keydown = 0x0100;     private const int wm_keyup = 0x0101;     private const int wm_syskeydown = 0x0104;     private const int wm_syskeyup = 0x0105;      private llkeyboardhook llkh;     public list<keys> hookedkeys = new list<keys>();      private intptr hook = intptr.zero;      public event keyeventhandler keydown;     public event keyeventhandler keyup;      public globalkeyboardhook()     {         llkh = new llkeyboardhook(hookproc);         hook();     }      ~globalkeyboardhook()     {         unhook();     }      public void hook()     {         intptr hinstance = loadlibrary("user32");         hook = setwindowshookex(wh_keyboard_ll, llkh, hinstance, 0);     }      public void unhook()     {         unhookwindowshookex(hook);     }      public int hookproc(int code, int wparam, ref keyboardhookstruct lparam)     {         if (code >= 0)         {             keys key = (keys) lparam.vkcode;             if (hookedkeys.contains(key))             {                 keyeventargs karg = new keyeventargs(key);                 if ((wparam == wm_keydown || wparam == wm_syskeydown) && (keydown != null))                     keydown(this, karg);                 else if ((wparam == wm_keyup || wparam == wm_syskeyup) && (keyup != null))                     keyup(this, karg);                 if (karg.handled)                     return 1;             }         }         return callnexthookex(hook, code, wparam, ref lparam);     }  } 

and use of in form

 globalkeyboardhook ghook;     public form1()     {         initializecomponent();         //new thread(samplefunction).start();     }      private void form1_load(object sender, eventargs e)     {         ghook = new globalkeyboardhook(); // create new globalkeyboardhook         // declare keydown event         ghook.keydown += new keyeventhandler(ghook_keydown);         // add keys want hook hookedkeys list         foreach (keys key in enum.getvalues(typeof(keys)))             ghook.hookedkeys.add(key);     }      // handle keydown event     public void ghook_keydown(object sender, keyeventargs e)     {         textbox1.text += ((char)e.keyvalue).tostring();     }      private void button1_click(object sender, eventargs e)     {         ghook.hook();     }      private void button2_click(object sender, eventargs e)     {         ghook.unhook();     }      private void form1_formclosing(object sender, formclosingeventargs e)     {         ghook.unhook();     }