Barcode scanner decode the code to decimal(3-digit) if I used evtkeyupeven

private string BarCode = "";
   private void evtKeyUpEvent(object sender, KeyEventArgs e)

   {
       if (Keys.NumPad0 <= e.KeyCode && e.KeyCode <= Keys.NumPad9)
       {
           BuildBarCode((e.KeyCode - Keys.NumPad0).ToString());
       }
       else if (Keys.D0 <= e.KeyCode && e.KeyCode <= Keys.D9)
       {

           BuildBarCode((e.KeyCode - Keys.D0).ToString());
       }
       if (65 <= e.KeyValue && e.KeyValue <= 90)
       {
           BuildBarCode((e.KeyCode).ToString());
       }
       else if (Keys.ShiftKey == e.KeyCode)
       {
       }
       else if (Keys.OemPeriod == e.KeyCode)
       {
           BuildBarCode(".");
       }
       else if (Keys.Multiply == e.KeyCode)
       {
           BuildBarCode("*");
       }
       else if (Keys.Add == e.KeyCode)
       {
           BuildBarCode("+");
       }
       else if (Keys.Separator == e.KeyCode)
       {
           BuildBarCode("|");
       }
       else if (Keys.Subtract == e.KeyCode)
       {
           BuildBarCode("-");
       }
       else if (Keys.Divide == e.KeyCode)
       {
           BuildBarCode("/");
       }
       else if (Keys.OemBackslash == e.KeyCode)
       {
           BuildBarCode(@"\");
       }
       else if (Keys.Separator == e.KeyCode)
       {
           BuildBarCode(",");
       }
       else if (Keys.OemMinus == e.KeyCode)
       {
           BuildBarCode("-");
       }

       else if (Keys.Space == e.KeyCode)
       {
           BuildBarCode(" ");
       }
       else if (Keys.OemCloseBrackets == e.KeyCode)
       {
           BuildBarCode(")");
       }
       else if (Keys.OemOpenBrackets == e.KeyCode)
       {
           BuildBarCode("(");
       }
       else if (Keys.Oemtilde == e.KeyCode)
       {
           BuildBarCode("~");
       }

       else if (Keys.Oemcomma == e.KeyCode)
       {
           BuildBarCode(",");
       }
       else if (Keys.OemSemicolon == e.KeyCode)
       {
           BuildBarCode(";");
       }
       else if (Keys.OemSemicolon == e.KeyCode)
       {
           BuildBarCode(";");
       }


       else if (e.KeyCode == Keys.Enter || e.KeyCode == Keys.Return)
       {
           updateUIBarCode(BarCode);
       }
   }
   private void BuildBarCode(string value)
   {
       BarCode = string.Concat(BarCode, value);
   }
   public void updateUIBarCode(string i)
   {
       AddNewRowWithCode(i);
   }