How to check whether Internet connection is avaialable or not

using System.Net;

WebRequest objWebReq;
   WebResponse objResp;
   public Boolean IsConnectionAvailable()
   {
       System.Uri objUrl = new System.Uri("http://www.google.com/");
     
       objWebReq = WebRequest.Create(objUrl);
      
       try
       {
           objResp = objWebReq.GetResponse();
           objResp.Close();
           objWebReq = null;
           return true;
       }
       catch (Exception ex)
       {
           objResp.Close();
           objWebReq = null;
           return false;
       }
   }

How to change the color of the selected item of drop downlist

<html>
<head>
  <title>
         change the color of the selected item
  </title>
     <script language="javascript">
          function chgColor(evt)
         {
              evt.options[evt.selectedIndex].style.background = 'red';
              for(i=0; i< evt.options.length;i++)
              {
                       if(i != evt.selectedIndex)
                       {
                               evt.options[i].style.background = '';
                       }
               }
         }
    </script>
</head>
<body>
        <select onchange="chgColor(this)">
                <option value="1">1</option>
                <option value="2">2</option>
                <option value="3">3</option>
                <option value="4">4</option>
                <option value="1">5</option>
                <option value="2">6</option>
                <option value="3">7</option>
                <option value="4">8</option>
                <option value="1">9</option>
                <option value="2">0</option>
         </select>
</body>

how to fix decimal places

Decimal.Round method used to a specified number of decimal places.

decimal.Round(99.2789m ,2).ToString();

Note

Without the suffix m, the number is treated as a double, thus generating a compiler error.

Output

99.28

How to convert strings to lower, upper, titlecase

string str = "xploReDOtneT wElcomeS yOU";

Response.Write("Orginal Text:- " + str + "
Lower :- " + str.ToLower() + "
" + "Upper :- " + str.ToUpper() + "
" + "Title Case :- " + System.Globalization.CultureInfo.CurrentCulture.TextInfo.ToTitleCase(str));



OUTPUT



Orginal Text:- xploReDOtneT wElcomeS yOU

Lower :- xploredotnet welcomes you

Upper :- XPLOREDOTNET WELCOMES YOU

Title Case :- Xploredotnet Welcomes You

Whats the difference between String.Emtpy and Empty Quotes

String.empty wont create any object while "" will create a new object in the memory for the checking.