How to write Singleton pattern in C#?

http://msdn.microsoft.com/en-us/library/ff650316.aspx

using System;

public sealed class Singleton
{
   private static volatile Singleton instance;
   private static object syncRoot = new Object();

   private Singleton() {}

   public static Singleton Instance
   {
      get 
      {
         if (instance == null) 
         {
            lock (syncRoot) 
            {
               if (instance == null) 
                  instance = new Singleton();
            }
         }

         return instance;
      }
   }
}

Code snippet for reading configuration from config file

System.Configuration.ConfigurationManager.AppSettings["SettingKey"] == null ? "defaultValue" : System.Configuration.ConfigurationManager.AppSettings["SettingKey"].ToString();

How to set new password without old one in ASP.NET Membership?

Reset password, then use reseted password as old password to set new one.

                 MembershipUser user = Membership.GetUser(username);
                string oldpassword = user.ResetPassword();
                user.ChangePassword(oldpassword, "newpassword");

Multiple Submit Buttons in ASP.NET MVC

In Razor view
@using (Html.BeginForm())
{
    <p>
        <input type="submit" name="AddButton" value="Add" />
        <input type="submit" name = "RemoveButton" value="Remove" />
    </p>
}

In Controller:

        [HttpPost]
        public ActionResult TwoButtonss(string AddButton, string RemoveButton)
        {
            var AddButtonClick = AddButton ?? RemoveButton;
            return View();
        }

Reference:
http://www.dotnetcurry.com/ShowArticle.aspx?ID=705

How to check a string is in valid number format in C#?

        public static bool IsNumber(string str)

        {

            double Number;

            if (double.TryParse(str, out Number)) return true;

            return false;

        }

What is OR operator in jQuery selector, Multiple selector

Comma (,)

Put comma between difference selectors, you can get combine result. OR operator.

$("div,span,p.myClass").css("border","3px solid red");

In jQuery, call Multiple selector

Reference: http://api.jquery.com/multiple-selector/

How to use Microsoft Translator service with screenshots and example

As the web grows, more and more international businesses are turning to the web. The demand for a multi-lingual website has never been so great. There are currently a few pay services out there that offer a translation API and also a few free ones (Google and Microsoft). One of the services that I have been looking at recently is the Microsoft Translator service. The API has support for SOAP, AJAX and HTTP which is a great addition to the API.

http://deanhume.com/Home/BlogPost/microsoft-translator-api/55 

Facebook like button

<iframe src="http://www.facebook.com/plugins/like.php?href=http%3A%2F%2Frayaspnet.blogspot.com%2F"
        scrolling="no" frameborder="0"
        style="border:none; width:350px; height:20px"><iframe></iframe></iframe>

How to hide iframe from inside iframe by Javascript?

parent.document.getElementById('iframecontainer').style.display = 'none';


//iframecontainer is the id of iframe.

How to disable scrolling bars for iframe?

How to disable scrolling bars for iframe?

    <div style="overflow:hidden;" >

            <iframe></iframe>

    </div>

Code Indentation and Nesting

Code Indentation and Nesting - Speed of Light

The greatest benefit of this style is bailing early. Instead of deeply nesting your code (and thus heavily indenting it), you have simple statements designed to end execution in as few instructions as possible, and designed to be as simple to follow as possible. Consider the examples:

        - (void)doSomethingWithString:(NSString *)s {
            if (nil != s) {
                if ([s length] > 0) {
                    NSLog(@"%@", s);
                }
            }
        }
        
        // VS
        - (void)doSomethingWithString:(NSString *)s {
            if (nil == s)
                return;
        
            if (![s length])
                return;
        
            NSLog(@"%@", s);
        }

ASP.NET FaceBook Login UserControl

http://www.eggheadcafe.com/tutorials/aspnet/fca40a96-aa44-4956-8382-447bf53f6035/aspnet-facebook-login-usercontrol.aspx

using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

namespace FacebookLogin
{
    public partial class FBLogin : System.Web.UI.UserControl
    {
         public static string FaceBookAppKey = ConfigurationManager.AppSettings["facebookAppKey"];

        protected void Page_Load(object sender, EventArgs e)
         {
             if(String.IsNullOrEmpty( FaceBookAppKey ))
                throw new InvalidOperationException("You must have a valid Facebook App Key in AppSettings element \"facebookAppKey\"");

             if (Request.Cookies["fbs_" + FaceBookAppKey] == null)
            {
                lblMessage.Text = "Not logged in.";
                 return; // No cookie returned from Facebook!!
            }

            string cookie = Request.Cookies["fbs_" + FaceBookAppKey].Value;
                cookie = cookie.Replace("\"", ""); //fix Facebook bug...
                NameValueCollection facebookValues = HttpUtility.ParseQueryString(cookie);

                  // send an http-request to facebook using the token from the cookie
                 //and parse the JSON response
                string json = GetFacebookUserJSON(facebookValues["uid"], facebookValues["access_token"]);
                Hashtable jsonHash = (Hashtable) JSON.JsonDecode(json);

                 //ok, let's actually read some data from FB response
                string facebookName = jsonHash["name"] as string;
                string firstName = jsonHash["first_name"] as string;
                string lastName = jsonHash["last_name"] as string;
                string facebookId = jsonHash["id"] as string;
                string email = jsonHash["email"] as string;
                     //We explicitly requested email (see fb-button)
            lblMessage.Text = "Welcome, " + firstName + " " + lastName + " [" + email + "]";

             // Can store name, email etc. in db here, get user profile, store info in Session, etc.
        }

         /// <summary>
        /// sends http-request to Facebook and returns the response string
        /// </summary>
        private static string GetFacebookUserJSON(string userid, string access_token)
        {
            string url = string.Format("https://graph.facebook.com/{0}?access_token={1}&fields=email,first_name,last_name", userid, access_token);
            WebClient wc = new WebClient();
            string s = wc.DownloadString(url);
             wc.Dispose();
             return s;
        }
    }
}

How to solve problem “Timeout expired. The timeout period elapsed prior to obtaining a connection from the pool. This may have occurred because all pooled connections were in use and max pool size was reached.”

How to solve problem “Timeout expired. The timeout period elapsed prior to obtaining a connection from the pool. This may have occurred because all pooled connections were in use and max pool size was reached.”

Reason: 

Usually do not close its associated connection when use a DataReader.

Three ways to solve:

1 SqlDataReader sdr = sCmd.ExecuteReader(System.Data.CommandBehavior.CloseConnection);

2 Explicitly close the connection

sc.Close();

3 Using block

using (SqlConnection sc = new SqlConnection(connString))

{

SqlCommand sCmd = new SqlCommand("SELECT * FROM Shippers", sc);

sc.Open();

Console.WriteLine("Conns opened " + i.ToString());

SqlDataReader sdr = sCmd.ExecuteReader();

sdr.Close();

}

AsyncController v/s SessionLess Controller

http://weblogs.asp.net/imranbaloch/archive/2011/05/10/asynccontroller-v-s-sessionless-controller.aspx



          AsyncController is introduced in ASP.NET MVC 2 while SessionLess controller is introduced in ASP.NET MVC 3. AsyncController allows you to perform long running I/O operation(s) without making your thread idle(i.e., waiting for I/O operations to complete). On the other hand, SessionLess controller allows you to execute multiple requests simultaneously for single user, which otherwise execute multiple requests sequentially due to session synchronization. Understanding these concepts may be easy for you but I have seen a lot of guys become confused on these concepts. In this article, I will show you how to use AsyncController and SessionLess controller in ASP.NET MVC application. I will also compare them and tell you what to use when, where, and the why.

How to show time cost for one query in T-SQL?

      DECLARE @starttime DATETIME2 = SYSDATETIME(), @alltime datetime2 = sysdatetime();

      DECLARE @finishtime INT;

/* Your query is in here */

      SELECT @finishtime = DATEDIFF(millisecond, @starttime, SYSDATETIME());

      PRINT '(ms): ' + CONVERT(VARCHAR, @finishtime)

What is Indexed view in MS SQL Server

Views are also known as virtual table, you can improve performance by creating a unique clustered index on the view.

Using the NOEXPAND View Hint
SELECT Column1, Column2, ... FROM Table1, View1 WITH (NOEXPAND) WHERE




http://msdn.microsoft.com/en-us/library/aa933148(v=SQL.80).aspx

How to get the checked radio button by jQuery

$(':radio').change(function () {

       $(':radio:checked').each(function () {

            if ($(this).val() == 2) {

                //Do stuff

                return;

            }

        });

    });

How to make a div stay fixed while scroll the page by CSS

style="position:fixed; top: 0%;"

NOT Opx 

How to set focus for first textbox in the web page by jQuery

$("#div1 :input[type='text']:first").focus();

How to make a full web page div (not full screen)?

            $('#divid').height($(document).height());